Core Java,J2EE,Hibernate,Spring,Php,Mysql Codes

Spring Setter Injection and Constructor Injection

2012-01-14T09:05:00.000-08:00

In this post i am going to demonstrate you how to set bean property using spring setter injection and constructor. First i will demonstrate Happy scenario and later will be complex. This will force you to think deeply about bean.xml

Consider i have class User containing 3 property name,age and country. Using spring i want to display value of user with all it's property.

User.java
package com.anuj.spring.injection;

/**
*
* @author Anuj J Patel
*
*/
public class User {

    private String name;
    private int age;
    private String country;

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getCountry() {
        return country;
    }
    public void setCountry(String country) {
        this.country = country;
    }

    public String toString()
    {
        String output = "Name : " + name + " Age: " + age + " Country:" + country;
        return output;
    }
}

UserApp.java
package com.anuj.spring.injection;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
*
* @author Anuj J Patel
*
*/
public class UserApp {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
        User user = (User) context.getBean("user");
        System.out.println(user);
    }
}

beans.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="user" class="com.anuj.spring.injection.User">
        <property name="name" value="Anuj"></property>
        <property name="age" value="24"></property>
        <property name="country" value="USA"></property>
    </bean>
</beans>

Output - Name : Anuj Age: 24 Country:USA

Constructor Injection :
public User(String name,int age,String country){
    this.name = name;
    this.age = age;
    this.country = country;
}
<constructor-arg value="Anuj"/>
<constructor-arg value="24"/>
<constructor-arg value="USA"/>

Output - Name : Anuj Age: 24 Country:USA

UnHappy Scenarios :)
If we have 2 constructor as mentioned below and beans xml contains only argument as shown below.
Now which constructor do you think will be invoked? The first one with the int and the String argument, right? But for your surprise it will call the second constructor with both String arguments. Though we know the first argument is of type int and the second argument is of type String, spring interprets both as String arguments

public User(int age,String country){
    this.age = age;
    this.country = country;
}
public User(String name,String country){
    this.name = name;
    this.country = country;
}
Output - Name : 24 Age: 0 Country:USA

Solution : To avoid this confusion you need to specify the type attribute of the constructor-arg element.
<constructor-arg value="24" type="int"/>
<constructor-arg value="USA" type="java.lang.String"/>
Output - Name : null Age: 24 Country:USA

Now consider this case. We have the following constructors in the User bean class and beans.xml entries.

public User(String name,int age){
    this.name = name;
    this.age = age;
}
public User(int age,String country){
    this.age = age;
    this.country = country;
}
<constructor-arg value="24" type="int"/>
<constructor-arg value="USA" type="java.lang.String"/>

Now which constructor do you think will be called? The second constructor, right? But again for your surprise the first constructor will be called, this is because the order in which the arguments appear in the bean configuration file will not be considered while invoking the constructor.
Output - Name : USA Age: 24 Country:null

To solve this problem you can use the index attribute to specify the constructor argument index.
Here is the bean configuration file after adding the index attribute.
<constructor-arg value="24" type="int" index="0"/>
<constructor-arg value="USA" type="java.lang.String" index="1"/>

Now Output will be : Name : null Age: 24 Country:USA ( Now i am damn happy :) )

Spring IOC and Dependancy Injection

2011-12-18T00:41:00.000-08:00

In Spring, Inversion of Control(IOC) is implemented using Dependancy Injection(DI) Design Pattern.Let's understand DI with java example and then we will see how DI can solve tightly coupled problem and Spring container will inject dependency.

QuizMaster.java
package anuj.spring.ioc;
/**
* @author Anuj J Patel
*
*/
public interface QuizMaster {
    public String popQuestion();
}

The StrutsQuizMaster and the SpringQuizMaster class implements QuizMaster interface and they generate questions related to struts and spring respectively.
SpringQuizMaster.java
package anuj.spring.ioc;
/**
*
* @author Anuj J Patel
*
*/
public class SpringQuizMaster implements QuizMaster{
@Override
public String popQuestion() {
    return "Are you new to Spring ?";
}
}

StrutsQuizMaster.java
package anuj.spring.ioc;
/**
*
* @author Anuj J Patel
*
*/
public class StrutsQuizMaster implements QuizMaster{
@Override
   public String popQuestion() {
     return "Are you new to Struts?";
}
}

QuizMasterService.java
package anuj.spring.ioc;
/**
*
* @author Anuj J Patel
*
*/
public class QuizMasterService {
QuizMaster quizMaster;
//QuizMaster quizMaster = new SpringQuizMaster(); tightly coupled
//QuizMaster quizMaster = new StrutsQuizMaster(); tightly coupled

public void setQuizMaster(QuizMaster quizMaster) {
     this.quizMaster = quizMaster;
}

public void askQuestion(){
      System.out.println(quizMaster.popQuestion());
   }
}

We have a QuizMasterService class that displays the question to the user. The QuizMasterService class holds reference to the QuizMaster.If we create instance of QuizMaster using QuizMaster quizMaster = new SpringQuizMaster(); Then this architecture is lightly coupled. and requried to modify class QuizMasterService if we want to use StrutsQuizMaster. Instead of hard coding any values we will allow the container to inject the required dependancies.

The Spring framework provides prowerful container to manage the components. The container is based on the Inversion of Control (IoC) principle and can be implemented by using the Dependency Injection (DI) design pattern. Here the component only needs to choose a way to accept the resources and the container will deliver the resource to the components.

The value for the QuizMaster will be set using the setQuizMaster() method. The QuizMaster object is never instantiated in the QuizMasterService class, but still we access it. Usually this will throw a NullPointerException, but here the container will instantiate the object for us, so it works fine

beans.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="springQuizMaster" class="anuj.spring.ioc.SpringQuizMaster"></bean>
    <bean id="strutsQuizMaster" class="anuj.spring.ioc.StrutsQuizMaster"></bean>
    <bean id="quizMasterService" class="anuj.spring.ioc.QuizMasterService">
        <property name="quizMaster">
            <ref local="springQuizMaster"/>
            
        </property>
    </bean>
</beans>

We define each bean using the bean tag. The id attribute of the bean tag gives a logical name to the bean and the class attribute represents the actual bean class. The property tag is used to refer the property of the bean. To inject a bean using the setter injection you need to use the ref tag

QuizProgram.java
package anuj.spring.ioc;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
*
* @author Anuj J Patel
*
*/
public class QuizProgram {

public static void main(String[] args) {
    ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
QuizMasterService quizMasterService = (QuizMasterService) context.getBean("quizMasterService");
    quizMasterService.askQuestion();
}
}

In order to run above examples, following are libraries which needs to be in Build Path.
--------------------------------------------------------------------------------------------
antlr-runtime-3.0
commons-logging-1.0.4
org.springframework.asm-3.0.0.M3
org.springframework.beans-3.0.0.M3
org.springframework.context-3.0.0.M3
org.springframework.context.support-3.0.0.M3
org.springframework.core-3.0.0.M3
org.springframework.expression-3.0.0.M3

What is Spring and why came into Picture ?

2011-12-12T09:00:00.000-08:00

In order to start with Spring, it's very important to clear concepts about what is Spring and why it came into picture. Once you have idea about Spring picture, you will be sure able to easily understand 7 Spring modules described here as well. So Let's Jump into Spring :)

In an enterprise application, business logic forms the basis of transforming the persisted data. That is the reason why the business logic layer is considered the most important layer of any enterprise application. Typically, the Java Enterprise Edition (JEE) component that was used to implement business logic was Enterprise Java Beans (EJB). However, EJBs are heavy weight components that require application servers to run.

This was the scenario before the Spring Framework came into the picture. The Spring Framework provides a lightweight container to run the objects implementing business logic. In other words, Spring Framework-based business objects do not require an application server to run.

Spring Framework: What is it?By definition the Spring Framework is “An open-source layered Java/J2EE application framework having a light-weight container implementing Inversion-of-Control and Aspect Oriented Programming.” The key points here are “layered application framework” and “Inversion of Control and Aspect Oriented Programming.” These key points can be divided into two broad categories:

Patterns
Components of the Framework

The former refers to the design patterns supported by Spring Framework and the latter refers to the components that build up the Framework.
Spring has two patterns at its core. They are:

Inversion-of-Control
Aspect Oriented Programming

The former is also called IoC and the latter is known as AOP. Here are the details.

Inversion-of-Control is called IoC for short. IoC “is a concept, and an associated set of programming techniques, in which the control flow is inverted compared to the traditional interaction model expressed in imperative style by a series of procedure calls.” In other words, the framework calls the procedures created by the programmer, rather than programmer calling the procedures or methods of the framework. IoC is also known as the “Hollywood Principle.” The Hollywood Principle says “Don’t call me, I will call you.”
IoC is used to ‘inject’ dependencies at runtime. When one uses this pattern, the dependencies of a particular object are not satisfied at compile time. Instead, the framework provides the required dependencies to the object at runtime. Thus, this pattern releases the programmer from the chore of providing all the dependencies at compile time.

Aspect Oriented Programming or AOP for short, is by definition “An approach to programming that attempts the separation of concerns, specifically cross-cutting concerns, as an advance in modularization.” Here, the key point is separation of concerns. Concern is another term for a module of an application, where module refers to a functionality of the application.
Separation of concerns means that the applications are divided into modules that do not overlap in terms of functionality. However, some functionalities or modules/concerns always overlap other modules/concerns. Logging is an example of such a concern. AOP provides techniques to encapsulate cross cutting or overlapping concerns. In other words, by using AOP a developer can encapsulate cross cutting concerns.
Spring provides both IoC as well as AOP. They are built into the core of the Spring Framework. The next aspect of the Spring Framework worth noting is its support for layered architecture. It provides this support through its various components. Some of them are:

MVC Component
IOC container
DAO support

These three cater to the Presentation, Business, and Persistence layers. Here is a brief overview:

MVC Component: The flexibility of the Spring Framework is that one can use any MVC framework with it. However, it also provides its own framework, called Spring MVC. Spring MVC implements MVC-Model 2 for JSP. It does this by providing controller Servlet and JSP taglib for you to view.

IoC Container: The business logic layer can be developed without coupling it with any other layers by using IoC provided by the Spring Framework. The IoC container is the core component of the framework. IoC lets the developer implement the business logic as Plain Old Java Objects (POJO) and wire them up so that they can be injected or called at runtime. This approach lets you avoid specifying the business objects as dependencies at compile time.

DAO Support: Any of the technologies, including JDBC, Hibernate, and iBatis, can be used with the Spring Framework to access persisted data. The Spring Framework provides this functionality through its DAO support component. A developer can plug in almost any of the persistence framework by using the DAO component.

Spring Framework Modules : Spring contains a lot of functionality and features, which are well-organized in seven modules shown in the diagram below

1. The Core package is the most fundamental part of the framework and provides the Dependency Injection features allowing you to manage bean container functionality. The basic concept here is the BeanFactory, which provides a factory pattern removing the need for programmatic singletons and allowing you to decouple the configuration and specification of dependencies from your actual program logic.

On top of the Core package sits the Context package, providing a way to access beans in a framework-style manner, somewhat resembling a JNDI-registry. The context package inherits its features from the beans package and adds support for text messaging using e.g. resource bundles, event-propagation, resource-loading and transparent creation of contexts by, for example, a servlet container.

2. The DAO package provides a JDBC-abstraction layer that removes the need to do tedious JDBC coding and parsing of database-vendor specific error codes. Also, the JDBC package provides a way to do programmatic as well as declarative transaction management, not only for classes implementing special interfaces, but for all your POJOs (plain old java objects).

3. The ORM package provides integration layers for popular object-relational mapping APIs, including JDO, Hibernate and iBatis. Using the ORM package you can use all those O/R-mappers in combination with all the other features Spring offers, like simple declarative transaction management mentioned before.

4. Spring's AOP package provides an AOP Alliance compliant aspect-oriented programming implementation allowing you to define, for example, method-interceptors and pointcuts to cleanly decouple code implementing functionality that should logically speaking be separated. Using source-level metadata functionality you can incorporate all kinds of behavioral information into your code, a little like .NET attributes.

5. Spring's Web package provides basic web-oriented integration features, such as multipart functionality, initialization of contexts using servlet listeners and a web-oriented application context. When using Spring together with WebWork or Struts, this is the package to integrate with.

6. Spring's Web MVC package provides a Model-View-Controller implementation for web-applications. Spring's MVC implementation is not just any implementation, it provides a clean separation between domain model code and web forms and allows you to use all the other features of the Spring Framework like validation.

Using Spring JdbcTemplate to store and retrive values into DB

2011-09-29T05:00:00.001-07:00

In This example i will demonstrate you Spring example to insert and select values from oracle DB. The insertForum() method below shows the amount of code you need to write to insert data using JDBC.

1. Create Java POJO Class ex. Forum which contains getter and setter method for field as mentioned below.
    private int forumId;
    private String forumName;
    private String forumDesc;

1.1 create parameterized constructor as below.
public Forum(int forumId, String forumName, String forumDesc) {
        this.forumId = forumId;
        this.forumName = forumName;
        this.forumDesc = forumDesc;
    }

2. Create Interface ex. ForumDAO which contains insert and select methods
package com.learning.dao;
import com.learning.core.Forum;
public interface ForumDAO {

    public void insertForum(Forum forum);
    public Forum selectForum(int forumId);
}

3. Create Imlementation file containting logic to perform insertion and retrival from DB.
package com.learning.dao;

import java.sql.ResultSet;
import java.sql.SQLException;

import javax.sql.DataSource;

import com.learning.core.Forum;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;

public class ForumDAOImpl implements ForumDAO{

    private JdbcTemplate jdbcTemplate;

    public void setDataSource(DataSource dataSource){
        this.jdbcTemplate = new JdbcTemplate(dataSource);
    }

    public void insertForum(Forum forum) {
        // TODO Auto-generated method stub
        String query = "INSERT INTO FORUMS (FORUM_ID, FORUM_NAME, FORUM_DESC) VALUES (?,?,?)";

        jdbcTemplate.update(query,new Object[]{Integer.valueOf(forum.getForumId()),
                forum.getForumName(), forum.getForumDesc()});
    }


    public Forum selectForum(int forumId) {
        // TODO Auto-generated method stub
        String query = "SELECT * FROM FORUMS WHERE FORUM_ID=?";

        return jdbcTemplate.queryForObject(query, new Object[]{Integer.valueOf(forumId)},
        new RowMapper(){
            public Object mapRow(ResultSet resultSet, int rowNum) throws SQLException {
                // TODO Auto-generated method stub
                return new Forum(resultSet.getInt("FORUM_ID"), resultSet.getString("FORUM_NAME"),
                        resultSet.getString("FORUM_DESC"));
            }
        }
        );
    }
}

Here you need to implement the mapRow() method of the RowMapper callback interface. In the mapRow() method, map the single row of the result set to the Forum object. The queryForObject() method takes a sql query, an array of Object that contains values to be bound to indexed parameters of the query and a RowMapper object.

You need not handle any database-related exceptions explicitly instead Spring JDBC Framework will handle it for you. All the exceptions thrown by the Spring JDBC Framework are subclasses of DataAccessException. The DataAccessException is a type of RuntimeException, so you are not forced to handle it. The SQLException is a checked exception, when you throw the SQLException here the Spring JDBC Framework will wrap this checked exception inside one of the subclasses of DataAccessException and rethrow it, this eliminates the need to explicitly handle them

4. Create beans xml e.g. spring-beans.xml in which we contains bean id of class and dataSource information.

Here we use Jakarta Commons Database Connection Pools (DBCP) to configure the datasource. The BasicDataSource can be easily configured and supports connection pooling. To use DBCP you need to have the following jar file in the classpath commons-dbcp.jar and commons-pool.jar. After creating the datasource inject the datasource to the DAO class. In the DAO class we use this datasource to create the JDBCTemplate object

5. create Main class to run Application :

ApplicationContext context = new ClassPathXmlApplicationContext("spring-beans.xml");
ForumDAO forumDAO = (ForumDAO) context.getBean("forumDAO");
Forum springForum = new Forum(1,"Spring Forum", "Discuss everything related to Spring");
forumDAO.insertForum(springForum);
System.out.println(forumDAO.selectForum(1));

Result :

Hibernate - Store and Retrieve Data along with BLOB as XML

2011-08-29T10:10:00.000-07:00

In order to use Hibernate, before you started you need to understand hibernate. Hibernate is an object-relational mapping (ORM) library for the Java language, providing a framework for mapping an object-oriented domain model to a traditional relational database.

Here, i have demostrated basic example to store data along with blob into Db and retrieve from DB.File logic is used to display Blob Data only. While writing your own Logic, you should avoid it.

hibernate.cfg.xml : get Hibernate config file

Contact.java - Pojo file containing getter and setter methods.

package com.core;

import java.io.Serializable;
import java.sql.Blob;

/**
* @author Anuj J Patel
* Java Core POJO class to map to database Contact Table
*/
public class Contact implements Serializable{
    private String firstName;
    private String lastName;
    private String email;
    private int id;
    private Blob contactData;

    public Blob getContactData() {
        return contactData;
    }
    public void setContactData(Blob contactData) {
        this.contactData = contactData;
    }
    public String getFirstName() {
        return firstName;
    }
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }
    public String getLastName() {
        return lastName;
    }    public void setLastName(String lastName) {
        this.lastName = lastName;
    }    public String getEmail() {
        return email;
    }    public void setEmail(String email) {
        this.email = email;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
}

Contact.hbm.xml : Actually mapping from Column to Table Column happening here
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
<class name="com.core.Contact" table="TBContact">
<id name="id" type="int" column="id" >
<generator class="assigned"/>
</id>

<property name="firstName">
<column name="firstName" />
</property>
<property name="lastName">
<column name="lastName"/>
</property>
<property name="email">
<column name="email"/>
</property>

<property name="contactData" type="java.sql.Blob">
<column name="ObjXML" />
</property>
</class>
</hibernate-mapping>

HibernateUtil.java - contains logic to initialized session factory
package com.configuration.hibernate;

import java.net.URL;

import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
/**
* @author Anuj J Patel
*/
public class HibernateUtil {
   private static final SessionFactory sessionFactory = buildSessionFactory();

    public static SessionFactory getSessionfactory() {
        return sessionFactory;
   }

    private static SessionFactory buildSessionFactory(){
        try{
            return new Configuration().configure().buildSessionFactory();
        }
        catch(Throwable ex){
            System.err.println("initial sessionFactory creation failed"+ex);
            throw new ExceptionInInitializerError(ex);
        }
   }

    public static void shutDown(){
        getSessionfactory().close();
    }
}

Store Data into DB :
package com.Test;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import org.hibernate.Hibernate;
import org.hibernate.Session;
import com.configuration.hibernate.HibernateUtil;
import com.core.Contact;
import java.sql.Blob;
import java.sql.SQLException;

import com.thoughtworks.xstream.XStream;
/**
* @author Anuj J Patel
*/
public class AddDataIntoDB {

    private static XStream xstream = new XStream();
    private static Session session = null;

    public static void main(String[] args) throws SQLException, IOException {
        // TODO Auto-generated method stub

        boolean flag = false;
        try {
            session = new HibernateUtil().getSessionfactory().openSession();
            session.beginTransaction();

            xstream.alias("Contact", Contact.class);

            Contact contact = new Contact(); contact.setId(1);
            contact.setFirstName("Anuj"); contact.setLastName("patel");
            contact.setEmail("anuj2009@gmail.com");

            String contactXML = xstream.toXML(contact);
            File inf = new File("contactXMLFile.xml");
            FileWriter fw = new FileWriter(inf);
            BufferedWriter out = new BufferedWriter(fw);
            out.write(contactXML);
            out.close();
            fw.close();

            InputStream is = new FileInputStream(inf);
            Blob contactData = (Blob) Hibernate.createBlob(is);
            contact.setContactData(contactData);

            session.save(contact);
            System.out.println("Writing to DB - Done!!");

            flag = true;
        } catch (Exception e) {
            e.printStackTrace();
            flag = false;
        } finally {
            // actually insertion happens at this place
            if (flag) {
                session.flush();
                session.close();
            }
        }
    }
}

Retrieve Data from DB :
package com.Test;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import org.hibernate.Query;
import org.hibernate.Session;
import com.configuration.hibernate.HibernateUtil;
import com.core.Contact;
import java.sql.Blob;
import java.sql.SQLException;
import java.util.Iterator;
import java.util.List;
/**
* @author Anuj J Patel
*/
public class readfromDB {

    private static final String SELECT_STATEMENT = "from Contact where id = :ID";
    private static Session session = null;

    public static void main(String[] args) throws SQLException, IOException {

        boolean flag = false;
        try {
            session = new HibernateUtil().getSessionfactory().openSession();
            session.beginTransaction();

            Query query = session.createQuery(SELECT_STATEMENT);
            query.setParameter("ID",'1');
            List lst = query.list();
            Iterator it = lst.iterator();
            while(it.hasNext()){
                Contact contact = (Contact) it.next();
                System.out.println(contact.getId());
                System.out.println(contact.getFirstName() + " " + contact.getLastName());
                System.out.println(contact.getEmail());

                Blob blob = contact.getContactData();
                try {
                    int bufferlen = (int) blob.length();
                    byte[] buffer = new byte[bufferlen];

                    File outf = new File("contactXMLFileRes.xml");
                    FileOutputStream fos = new FileOutputStream(outf);
                    InputStream ins = blob.getBinaryStream();
                    while (ins.read(buffer) > 0) {
                        fos.write(buffer);
                      }
                    fos.close();
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }

            flag = true;
        } catch (Exception e) {
            e.printStackTrace();
            flag = false;
        } finally {
            if (flag) {
                session.flush();
                session.close();
            }
        }
    }
}

How to write Code in Java?

2011-07-26T08:18:00.000-07:00

If you Google then you will find lots of code and solution of your coding issue. but
The most important point is How Code should be?
When you are writing code in Java, As per my knowledge - There are points which should be implemented into code

Key Pointes are :

1. Always generate logs for your application.You can use apache Log4j.jar for that.

2. Don't generate log file into root of your application. Try to create new Log directory into your application,
   and generate new log file for earch Run/Build into log folder

3. Naming convension of log file is important as well. it should be Ex. _DataandTimeStamp.log.
   In order to create new log file each time your applicaton runs, you can create inherit superclass FileAppender
   and overrid it's method and write logic to create new name with timestamp.

4. If your application require Global variable,which will be used throught your appplication(like Configuration) then you
   should make define it into Properties and access it using ResourceBundle from Java.util package.

5. Exception Handling is one of the important factor which should be implemented into your program.

6. Don't use static absolute path. Better to use relative path Ex. path config/Resource.properties is better than
   c:/myproject/src/config/Resource.properties

7. Write all your java files into packages rather than in Default package

8. if your application requires some thirdparty jar to be used, then copy all required jars into lib directory and
   all to build path of your application.

9. write Ant Script which perform operation like, clean the build,compile java files and generate java classes, Generate
   .jar file from generated classes and add Main-Class to manifest.mf, and run.
   By using Ant Script,It's easy to figure out if there are any compilation or runtime error exist or not.

10. Always write Interface.Code should be written such that if there is any need to do customization to existing code in future,
    Then it can be done by writing subclasses which inherited from Super Class,override method and add your own logic into it.

11. Sometime using keyword "public" will solve your issues but It's very important to make use of keyword "private and protected"
    along with "Public".

12. If there is bunch of code for parsign XML is there, then It's better to write function Ex. parseXML(String XMLFile) into which
    you can pass XMLFilename as parameter and write your logic there.

13. keep usage of POJO classes and getter,setter method in it.

14. write JUnit classes to test application with various input condition.

15. Always make proper versioning of your application so it is easy to figure out which version contains which features.

16. Each application should have it's functional document mentioning which functionality included into given version.

Marshelling and Unmarshelling Document using JAXB

2011-07-10T09:21:00.000-07:00

Marshelling is a process of transforming java classes into XML format. and Unmarshalling is the process of converting an XML document into a corresponding set of Java objects.

To understand how to process XML documents in Java with JAXB 2.0, we need to look at the two main JAXB components:
The binding compiler, which binds a given XML schema to a set of generated Java classes
The binding runtime framework, which provides unmarshalling, marshalling, and validation functionalities

Concept 1 : JAXB Binding Compiler:
The JAXB binding compiler (or xbj) lets you generate Java classes from a given XML schema. The JAXB binding compiler transforms an XML schema into a collection of Java classes that match the structure described in the XML schema. These classes are annotated with special JAXB annotations, which provide the runtime framework with the mappings it needs to process the corresponding XML documents

Pre-Setup:
1.Before you started you need XML Schema presentation for your XML which you can generate from my blog post generate xsd schema file from xml
2.Install JWSDP(java webservice Developer pack) 2.0 which provide support for JAXB and allows you to generate java classes based on XML Schema.
3.Generate java files using command as : xjc <.xsd file generated from XML>

Concept 2 : Marshelling Document
Create JAXBContext object as per your project as
JAXBContext jaxbContext;
jaxbContext = JAXBContext.newInstance("com.anuj.jaxb");

Once your domain object is initialized, use the JAXB context to create a Marshaller object and a typed JAXBElement. Creating the marshaller is simple:
Marshaller marshaller = jaxbContext.createMarshaller();

Next, you create a JAXBElement object that encapsulates your domain object. The typed JAXBElement corresponds to the root element complexType of your XML document. Then use the generated ObjectFactory class as follows:
JAXBElement bookingElement = (new ObjectFactory()).createBooking(booking);

Set a property so that the output will be formatted for human use and then write to standard output
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
marshaller.marshal( bookingElement, System.out ); Outout will be XML.

Based on Java Classes generated from XML Schema file, add details to Object. Then We can apply Marshelling on this to create XML Document.

CourseBooking booking = new CourseBooking();
booking.setCourseReference("UML-101");
booking.setTotalPrice(new BigDecimal(10000));
booking.setInvoiceReference("123456");
DatatypeFactory datatypes = DatatypeFactory.newInstance();
booking.setCourseDate(datatypes.newXMLGregorianCalendarDate(2006,06,15,0));
booking.setTotalPrice(new BigDecimal(10000));
booking.setInvoiceReference("123456");
booking.getStudent().add(new StudentType());
booking.getStudent().get(0).setFirstName("John");
booking.getStudent().get(0).setSurname("Smith");
booking.setCompany(new CompanyType());
booking.getCompany().setName("Clients inc.");
booking.getCompany().setContact(new ContactType());
booking.getCompany().getContact().setName("Paul");
booking.getCompany().getContact().setEmail("paul@clients.inc");
booking.getCompany().getContact().setTelephone("12345678");
booking.getCompany().setAddress("10 client street");

Concept 3 : Unmarshelling Document
To unmarshall an XML document, you create an Unmarshaller from the context, as shown here:
Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();

The unmarshaller can process XML data from a wide variety of data sources: files, input streams, URLs, DOM objects, SAX parsers, and more.
Here we provide a simple File object pointing to our XML document. The unmarshaller returns a typed JAXBElement, from which we can obtain our unmarshalled object by using the getValue() method:

JAXBElement element = (JAXBElement) u.unmarshal (new StringReader(writer.toString()));
CourseBooking cbook= (CourseBooking) element.getValue ();
System.out.println ("Company Name : " + cbook.getCompany().getName());

Happy Coding...

Generate .xsd Schema file from .xml file

2011-07-09T23:52:00.000-07:00

When you are using JAXB(Java Architecture for XML Binding), you must require xml document to be converted into .xsd file. There is one Open Source called "trang" which does same thing. It takes .xml file as input and give .xsd as output. You can also use XMLSpy but It's not free. you will be provided 30 days trial.

1. Download "Trang"and Copy .jar files to local
2. Generate .xsd file using command as below using command prompt

java -jar trang.jar app-defaults.xml app-defaults.xsd

Note : app-defaults.xml is existing input .xml file and app-defaults.xsd is file which will generate after running this command.

app-defaults.xml
<?xml version="1.0" encoding="UTF-8"?>
<AppDefaults>
<RegionMasterURL>http://bitrazor.com/content/tivo/hme/trafficcam/RegionMaster.xml</RegionMasterURL>
<ShowTime>4500</ShowTime>
<FadeTime>750</FadeTime>
<DefaultRegion>97205</DefaultRegion>
</AppDefaults>

app-defaults.xsd
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">
<xs:element name="AppDefaults">
<xs:complexType>
<xs:sequence>
<xs:element ref="RegionMasterURL"/>
<xs:element ref="ShowTime"/>
<xs:element ref="FadeTime"/>
<xs:element ref="DefaultRegion"/>
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="RegionMasterURL" type="xs:anyURI"/>
<xs:element name="ShowTime" type="xs:integer"/>
<xs:element name="FadeTime" type="xs:integer"/>
<xs:element name="DefaultRegion" type="xs:integer"/>
</xs:schema>

Develop First App in Android

2010-10-31T06:45:00.000-07:00

1. Android SDK Kit
You can get the latest version of the SDK starter package from the SDK download page. Make sure to download the package that is appropriate for your development computer.

2. Installing the ADT Plugin for Eclipse
Follow instruction mentioned at Eclipse ADT Installation and Configuration

3. Launching the Android SDK and AVD Manager
The Android SDK and AVD Manager is the tool that you use to install and upgrade SDK components in your development environment.

You can access the tool in any of three ways:

    * If you are developing in the Eclipse IDE with the ADT Plugin, you can access the tool directly from the Eclipse UI.
    * On Windows only, you can launch he tool by double-clicking a script file.
    * In all environments, you can access the tool from a command line.

Launching from Eclipse/ADT

If you are developing in Eclipse and have already installed the ADT Plugin, follow these steps to access the Android SDK and AVD Manager tool:
   1. Open Eclipse
   2. Select Window > Android SDK and AVD Manager.
HelloAndroid.java

package com.example.helloandroid;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class HelloAndroid extends Activity {
   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       TextView tv = new TextView(this);
       tv.setText("Anuj, Congo for First Android App");
       setContentView(tv);
   }
}

Calculate GeoDistance between two points using Java

2010-08-16T07:16:00.001-07:00

This program help to determine Geo Distance between two points using java.
you have to passe longitude and latitude of two different points as arguments to function Distance

package anuj.stuff;

public class GeoDistance {

private static Double geomile;
private static Double geokil;
private static Double NauMile;

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub

geomile = distance(32.9697, -96.80322, 29.46786, -98.53506, "M");
System.out.println(geomile + " Miles\n");
geokil = distance(32.9697, -96.80322, 29.46786, -98.53506, "K");
System.out.println(geokil + " Kilometers\n");
NauMile = distance(32.9697, -96.80322, 29.46786, -98.53506, "N");
System.out.println(NauMile + " Nautical Miles\n");

}

private static double distance(double lat1, double lon1, double lat2, double lon2, String unit) {
double theta = lon1 - lon2;
double dist = Math.sin(deg2rad(lat1)) * Math.sin(deg2rad(lat2)) + Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2)) * Math.cos(deg2rad(theta));
dist = Math.acos(dist);
dist = rad2deg(dist);
dist = dist * 60 * 1.1515;
if (unit.equals("K")) {
dist = dist * 1.609344;
} else if (unit.equals("N")) {
dist = dist * 0.8684;
}
return (dist);
}

//converts decimal degrees to radians
private static double deg2rad(double deg) {
return (deg * Math.PI / 180.0);
}

//converts radians to decimal degrees
private static double rad2deg(double rad) {
return (rad * 180.0 / Math.PI);
}

}

Take screen shot of current window using Java

2010-08-16T06:39:00.001-07:00

This example uses java.awt.Robot class to capture the screen pixels and returns a BufferedImage. Java.awt.Robot class is used to take the control of mouse and keyboard. Once you get the control, you can do any type of operation related to mouse and keyboard through your java code

package anuj.stuff;

import java.awt.Dimension;
import java.awt.Rectangle;
import java.awt.Robot;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
import java.io.File;

public class ScreenShots {

/**
* @param args
* @throws Exception
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
ScreenShots shots = new ScreenShots();
try {
shots.captureScreen("CapturedImage.png");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

//take screen shots of current window
public void captureScreen(String fileName) throws Exception {

Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
Rectangle screenRectangle = new Rectangle(screenSize);
Robot robot = new Robot();
BufferedImage image = robot.createScreenCapture(screenRectangle);
ImageIO.write(image, "png", new File(fileName));

}

}

Merge two PDF into one and Split one PDf into two PDF using java

2010-08-12T03:45:00.001-07:00

In order to use this code you need open source lib iText.jar.you can download using link mentioned in my one of blog post "Generate PDf using java".

ConcatPDFs function helps you to merger two pdf say anuj1.pdf and anuj2.pdf into anujmerge.

Using function split pdf,you can split existing one pdf( say having 2 pages) into two seperate pdf say,output1.pdf(page 1 to 1) and output2.pdf(page 2 to 2).

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import com.lowagie.text.Document;
import com.lowagie.text.pdf.BaseFont;
import com.lowagie.text.pdf.PdfContentByte;
import com.lowagie.text.pdf.PdfImportedPage;
import com.lowagie.text.pdf.PdfReader;
import com.lowagie.text.pdf.PdfWriter;

public class MergePDF {

public static void main(String[] args) {
try {
List pdfs = new ArrayList();
pdfs.add(new FileInputStream("c:\\Anuj1.pdf"));
pdfs.add(new FileInputStream("c:\\Anuj2.pdf"));
OutputStream output = new FileOutputStream("c:\\Anujmerge.pdf");
MergePDF.concatPDFs(pdfs, output, true);

//split an input.pdf
try {
MergePDF.splitPDF(new FileInputStream("C:\\Anujmerge.pdf"),
new FileOutputStream("C:\\output1.pdf"), 1, 1);
MergePDF.splitPDF(new FileInputStream("C:\\Anujmerge.pdf"),
new FileOutputStream("C:\\output2.pdf"), 2, 2);

} catch (Exception e) {
e.printStackTrace();
}

} catch (Exception e) {
e.printStackTrace();
}
}

public static void concatPDFs(List streamOfPDFFiles,
OutputStream outputStream, boolean paginate) {

Document document = new Document();
try {
List pdfs = streamOfPDFFiles;
List readers = new ArrayList();
int totalPages = 0;
Iterator iteratorPDFs = pdfs.iterator();

// Create Readers for the pdfs.
while (iteratorPDFs.hasNext()) {
InputStream pdf = iteratorPDFs.next();
PdfReader pdfReader = new PdfReader(pdf);
readers.add(pdfReader);
totalPages += pdfReader.getNumberOfPages();
}
// Create a writer for the outputstream
PdfWriter writer = PdfWriter.getInstance(document, outputStream);

document.open();
BaseFont bf = BaseFont.createFont(BaseFont.HELVETICA,
BaseFont.CP1252, BaseFont.NOT_EMBEDDED);
PdfContentByte cb = writer.getDirectContent(); // Holds the PDF
// data

PdfImportedPage page;
int currentPageNumber = 0;
int pageOfCurrentReaderPDF = 0;
Iterator iteratorPDFReader = readers.iterator();

// Loop through the PDF files and add to the output.
while (iteratorPDFReader.hasNext()) {
PdfReader pdfReader = iteratorPDFReader.next();

// Create a new page in the target for each source page.
while (pageOfCurrentReaderPDF < pdfReader.getNumberOfPages()) { document.newPage(); pageOfCurrentReaderPDF++; currentPageNumber++; page = writer.getImportedPage(pdfReader, pageOfCurrentReaderPDF); cb.addTemplate(page, 0, 0); // Code for pagination. if (paginate) { cb.beginText(); cb.setFontAndSize(bf, 9); cb.showTextAligned(PdfContentByte.ALIGN_CENTER, "" + currentPageNumber + " of " + totalPages, 520, 5, 0); cb.endText(); } } pageOfCurrentReaderPDF = 0; } outputStream.flush(); document.close(); outputStream.close(); } catch (Exception e) { e.printStackTrace(); } finally { if (document.isOpen()) document.close(); try { if (outputStream != null) outputStream.close(); } catch (IOException ioe) { ioe.printStackTrace(); } } } public static void splitPDF(InputStream inputStream, OutputStream outputStream, int fromPage, int toPage) { Document document = new Document(); try { PdfReader inputPDF = new PdfReader(inputStream); int totalPages = inputPDF.getNumberOfPages(); //make fromPage equals to toPage if it is greater if(fromPage > toPage ) {
fromPage = toPage;
}
if(toPage > totalPages) {
toPage = totalPages;
}

// Create a writer for the outputstream
PdfWriter writer = PdfWriter.getInstance(document, outputStream);

document.open();
PdfContentByte cb = writer.getDirectContent(); // Holds the PDF data
PdfImportedPage page;

while(fromPage <= toPage) {
document.newPage();
page = writer.getImportedPage(inputPDF, fromPage);
cb.addTemplate(page, 0, 0);
fromPage++;
}
outputStream.flush();
document.close();
outputStream.close();
} catch (Exception e) {
e.printStackTrace();
} finally {
if (document.isOpen())
document.close();
try {
if (outputStream != null)
outputStream.close();
} catch (IOException ioe) {
ioe.printStackTrace();
}
}
}
}

Generate PDF using Java

2010-08-12T01:59:00.001-07:00

It is very easy to generate a simple PDF file in Java using iText. All you have to do is to put itext.jar in your class path and paste following code in GeneratePDF.java class and compile and execute it

you need to used open source lib iText-2.1.5.jar and following code.it's done.

Download lib from : iText.jar

import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.util.Date;
import com.lowagie.text.Document;
import com.lowagie.text.Paragraph;
import com.lowagie.text.pdf.PdfWriter;
public class GeneratePDF {
public static void main(String[] args) {
try {
OutputStream file = new FileOutputStream(new File("C:\\Anuj.pdf"));
Document document = new Document();
PdfWriter.getInstance(document, file);

document.open();
document.addAuthor("Anuj j patel");
document.addCreationDate();
document.addCreator("Anuj Patel");
document.addTitle("Sample PDF using Java");
document.add(new Paragraph("Hello Anuj"));
document.add(new Paragraph(new Date().toString()));
document.close();
file.close();

} catch (Exception e) {
e.printStackTrace();
}
}
}

J2ME - Read and write using RMS

2010-07-16T05:22:00.001-07:00

This is sample application to read and write record using RMS in J2ME mobie application

import javax.microedition.rms.*;

import javax.microedition.midlet.*;

import javax.microedition.lcdui.*;

import javax.microedition.io.*;

public class ReadWrite extends MIDlet

{
private RecordStore rs = null;
static final String REC_STORE = "db_1";

public ReadWrite()
{
openRecStore(); // Create the record store

// Write a few records and read them back
writeRecord("J2ME and MIDP");
writeRecord("Wireless Technology");
readRecords();

closeRecStore(); // Close record store
deleteRecStore(); // Remove the record store
}

public void destroyApp( boolean unconditional )
{
}

public void startApp()
{
// There is no user interface, go ahead and shutdown
destroyApp(false);
notifyDestroyed();
}

public void pauseApp()
{
}

public void openRecStore()
{
try
{
// The second parameter indicates that the record store
// should be created if it does not exist
rs = RecordStore.openRecordStore(REC_STORE, true );
}
catch (Exception e)
{
db(e.toString());
}
}

public void closeRecStore()
{
try
{
rs.closeRecordStore();
}
catch (Exception e)
{
db(e.toString());
}
}

public void deleteRecStore()
{
if (RecordStore.listRecordStores() != null)
{
try
{
RecordStore.deleteRecordStore(REC_STORE);
}
catch (Exception e)
{
db(e.toString());
}
}
}

public void writeRecord(String str)
{
byte[] rec = str.getBytes();

try
{
rs.addRecord(rec, 0, rec.length);
}
catch (Exception e)
{
db(e.toString());
}
}

public void readRecords()
{
try
{
// Intentionally make this too small to test code below
byte[] recData = new byte[5];
int len;

for (int i = 1; i <= rs.getNumRecords(); i++) { if (rs.getRecordSize(i) > recData.length)
recData = new byte[rs.getRecordSize(i)];

len = rs.getRecord(i, recData, 0);
System.out.println("Record #" + i + ": " + new String(recData, 0, len));
System.out.println("------------------------------");
}
}
catch (Exception e)
{
db(e.toString());
}
}

private void db(String str)
{
System.err.println("Msg: " + str);
}
}

Develop Charts in JSP and Java

2010-07-03T00:04:00.000-07:00

I have just used Jfreechart and developed Pie chart displayed on JSP webpage deployed on tomcat.
If you need any assistance/code for this. then tweet me at http://twitter.com/#!/AnujJPatel

PDF to text parser using java

2010-06-13T00:41:00.000-07:00

Below class PDFTextParser takes PDf as input and convert it into test.In otder to use it,you need .jar file of pdfbox which is jakatra project in order to use below code.

Download PDF Box : Apache PDFBox

import org.pdfbox.cos.COSDocument;
import org.pdfbox.pdfparser.PDFParser;
import org.pdfbox.pdmodel.PDDocument;
import org.pdfbox.pdmodel.PDDocumentInformation;
import org.pdfbox.util.PDFTextStripper;

import java.io.File;
import java.io.FileInputStream;
import java.io.PrintWriter;

public class PDFTextParser {

PDFParser parser;
String parsedText;
PDFTextStripper pdfStripper;
PDDocument pdDoc;
COSDocument cosDoc;
PDDocumentInformation pdDocInfo;

// PDFTextParser Constructor
public PDFTextParser() {
}

// Extract text from PDF Document
String pdftoText(String fileName) {

System.out.println("Parsing text from PDF file " + fileName + "....");
File f = new File(fileName);

if (!f.isFile()) {
System.out.println("File " + fileName + " does not exist.");
return null;
}

try {
parser = new PDFParser(new FileInputStream(f));
} catch (Exception e) {
System.out.println("Unable to open PDF Parser.");
return null;
}

try {
parser.parse();
cosDoc = parser.getDocument();
pdfStripper = new PDFTextStripper();
pdDoc = new PDDocument(cosDoc);
parsedText = pdfStripper.getText(pdDoc);
} catch (Exception e) {
System.out.println("An exception occured in parsing the PDF Document.");
e.printStackTrace();
try {
if (cosDoc != null) cosDoc.close();
if (pdDoc != null) pdDoc.close();
} catch (Exception e1) {
e.printStackTrace();
}
return null;
}
System.out.println("Done.");
return parsedText;
}

// Write the parsed text from PDF to a file
void writeTexttoFile(String pdfText, String fileName) {

System.out.println("\nWriting PDF text to output text file " + fileName + "....");
try {
PrintWriter pw = new PrintWriter(fileName);
pw.print(pdfText);
pw.close();
} catch (Exception e) {
System.out.println("An exception occured in writing the pdf text to file.");
e.printStackTrace();
}
System.out.println("Done.");
}

//Extracts text from a PDF Document and writes it to a text file
public static void main(String args[]) {

if (args.length != 2) {
System.out.println("Usage: java PDFTextParser ");
System.exit(1);
}

PDFTextParser pdfTextParserObj = new PDFTextParser();
String pdfToText = pdfTextParserObj.pdftoText(args[0]);

if (pdfToText == null) {
System.out.println("PDF to Text Conversion failed.");
}
else {
System.out.println("\nThe text parsed from the PDF Document....\n" + pdfToText);
pdfTextParserObj.writeTexttoFile(pdfToText, args[1]);
}
}
}

Hibernet and Hibernet Dialect Properties

2010-05-07T20:56:00.000-07:00

Hibernate supports many database.we can use the following databases dialect type property:

* DB2 - org.hibernate.dialect.DB2Dialect
* HypersonicSQL - org.hibernate.dialect.HSQLDialect
* Informix - org.hibernate.dialect.InformixDialect
* Ingres - org.hibernate.dialect.IngresDialect
* Interbase - org.hibernate.dialect.InterbaseDialect
* Pointbase - org.hibernate.dialect.PointbaseDialect
* PostgreSQL - org.hibernate.dialect.PostgreSQLDialect
* Mckoi SQL - org.hibernate.dialect.MckoiDialect
* Microsoft SQL Server - org.hibernate.dialect.SQLServerDialect
* MySQL - org.hibernate.dialect.MySQLDialect
* Oracle (any version) - org.hibernate.dialect.OracleDialect
* Oracle 9 - org.hibernate.dialect.Oracle9Dialect
* Progress - org.hibernate.dialect.ProgressDialect
* FrontBase - org.hibernate.dialect.FrontbaseDialect
* SAP DB - org.hibernate.dialect.SAPDBDialect
* Sybase - org.hibernate.dialect.SybaseDialect
* Sybase Anywhere - org.hibernate.dialect.SybaseAnywhereDialect

Imp configuration file : hibernate.cfg.xml and Javaclass.hbm.xml and JavaClass as per requirement

The following two xml file are used while interacting with eclipse

hibernet.cfg.xml
----------------------------
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost/hibernatetutorial</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password"></property>
<property name="hibernate.connection.pool_size">10</property>
<property name="show_sql">true</property>
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.hbm2ddl.auto">update</property>

<mapping resource="contact.hbm.xml"/>
</session-factory>
</hibernate-configuration>

contact.hbm.xml
----------------------------

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="Classes.Contact" table="CONTACT">
<id name="id" type="long" column="ID" >
<generator class="assigned"/>
</id>
<property name="firstName">
<column name="FIRSTNAME" />
</property>
<property name="lastName">
<column name="LASTNAME"/>
</property>
<property name="email">
<column name="EMAIL"/>
</property>
</class>
</hibernate-mapping>

Contact.java
-------------------

package Classes;
public class Contact {
private String firstName;
private String lastName;
private String email;
private long id;

/**
* @return Email
*/
public String getEmail() {
return email;
}

/**
* @return First Name
*/
public String getFirstName() {
return firstName;
}

/**
* @return Last name
*/
public String getLastName() {
return lastName;
}

/**
* @param string Sets the Email
*/
public void setEmail(String string) {
email = string;
}

/**
* @param string Sets the First Name
*/
public void setFirstName(String string) {
firstName = string;
}

/**
* @param string sets the Last Name
*/
public void setLastName(String string) {
lastName = string;
}

/**
* @return ID Returns ID
*/
public long getId() {
return id;
}

/**
* @param l Sets the ID
*/
public void setId(long l) {
id = l;
}

}

Linked List using java

2010-04-28T10:40:00.003-07:00

package com.sys;

import java.util.LinkedList;

public class LinkList {

/**
* @param args
*/
@SuppressWarnings("unchecked")
public static void main(String[] args) {
// TODO Auto-generated method stub
LinkedList l = new LinkedList();
l.clear();
l.add("A");
l.add("J");
l.add("P");
l.addFirst("Hello");
l.addLast("Demo");
System.out.println(l);

//change Hello to Java
//Object val = l.get(0);
//System.out.println((String)val);
l.set(0, "java");
System.out.println(l);
l.clear();

}

}

Stack using java

2010-04-28T10:40:00.001-07:00

package com.sys;

import java.util.Stack;

public class Stacks {

/**
* @param args
*/
static void dopush(Stack s,int a){
s.push(a);
System.out.println("Push - " + a);
System.out.println("Stack is - "+ s);
}
static void dopop(Stack s){
Integer a = (Integer)s.pop();
System.out.println("POP - "+a);
System.out.println("Stack is - "+s);
}
public static void main(String[] args) {
// TODO Auto-generated method stub
Stack s = new Stack();
System.out.println("Stack " + s);
dopush(s, 1);
dopush(s, 2);
dopush(s, 3);
dopush(s, 4);
try{
dopop(s);
dopop(s);
dopop(s);
dopop(s);
dopop(s);
}
catch(Exception e){
//System.out.println(e);
System.out.println("Empty Stack");
}
}

}

Vector using java

2010-04-28T10:38:00.000-07:00

package com.sys;

import java.util.Enumeration;
import java.util.Vector;

public class Vectors {

/**
* @param args
*/
@SuppressWarnings("unchecked")
public static void main(String[] args) {
// TODO Auto-generated method stub
Vector v = new Vector();
v.addElement("1");
v.addElement("4");
v.addElement("2");
v.addElement("3");
//System.out.println(v);
Enumeration e = v.elements();
while(e.hasMoreElements()){
System.out.println(e.nextElement());
}
}

}

Getting System Properties using java

2010-04-28T10:37:00.000-07:00

package com.sys;

import java.util.*;

public class SystemPro {

/**
* @param args
*/
@SuppressWarnings("unchecked")
public static void main(String[] args) {
// TODO Auto-generated method stub
Properties p = System.getProperties();
//System.out.println(p);
Set s = p.entrySet();
Iterator i = s.iterator();
while(i.hasNext()){
Map.Entry me = (Map.Entry)i.next();
System.out.println(me.getKey() + " - " + me.getValue());
//Object o = i.next();
//System.out.println(o);
}

}
}

Working with Excel using java

2010-01-01T00:52:00.000-08:00

To run this u will require jxl.jar

Create.java
------------------------
import java.io.*;
import jxl.*;
import java.util.*;
import jxl.Workbook;
import jxl.write.Number;
import jxl.write.*;

class Create {
public static void main(String[] args) {
try {
String filename = "input.xls";
WorkbookSettings ws = new WorkbookSettings();
ws.setLocale(new Locale("en", "EN"));
WritableWorkbook workbook = Workbook.createWorkbook(new File(
filename), ws);
WritableSheet s = workbook.createSheet("Sheet1", 0);
WritableSheet s1 = workbook.createSheet("Sheet1", 0);
writeDataSheet(s);
writeImageSheet(s1);
workbook.write();
workbook.close();
} catch (IOException e) {
e.printStackTrace();
} catch (WriteException e) {
e.printStackTrace();
}
}

private static void writeDataSheet(WritableSheet s) throws WriteException {

/* Format the Font */
WritableFont wf = new WritableFont(WritableFont.ARIAL, 10,
WritableFont.BOLD);
WritableCellFormat cf = new WritableCellFormat(wf);
cf.setWrap(true);

/* Creates Label and writes date to one cell of sheet */
Label l = new Label(0, 0, "Date", cf);
s.addCell(l);
WritableCellFormat cf1 = new WritableCellFormat(DateFormats.FORMAT9);

DateTime dt = new DateTime(0, 1, new Date(), cf1, DateTime.GMT);

s.addCell(dt);

/* Creates Label and writes float number to one cell of sheet */
l = new Label(2, 0, "Float", cf);
s.addCell(l);
WritableCellFormat cf2 = new WritableCellFormat(NumberFormats.FLOAT);
Number n = new Number(2, 1, 3.1415926535, cf2);
s.addCell(n);

n = new Number(2, 2, -3.1415926535, cf2);
s.addCell(n);

/*
* Creates Label and writes float number upto 3 decimal to one cell of
* sheet
*/
l = new Label(3, 0, "3dps", cf);
s.addCell(l);
NumberFormat dp3 = new NumberFormat("#.###");
WritableCellFormat dp3cell = new WritableCellFormat(dp3);
n = new Number(3, 1, 3.1415926535, dp3cell);
s.addCell(n);

/* Creates Label and adds 2 cells of sheet */
l = new Label(4, 0, "Add 2 cells", cf);
s.addCell(l);
n = new Number(4, 1, 10);
s.addCell(n);
n = new Number(4, 2, 16);
s.addCell(n);
Formula f = new Formula(4, 3, "E1+E2");
s.addCell(f);

/* Creates Label and multipies value of one cell of sheet by 2 */
l = new Label(5, 0, "Multipy by 2", cf);
s.addCell(l);
n = new Number(5, 1, 10);
s.addCell(n);
f = new Formula(5, 2, "F1 * 3");
s.addCell(f);

/* Creates Label and divide value of one cell of sheet by 2.5 */
l = new Label(6, 0, "Divide", cf);
s.addCell(l);
n = new Number(6, 1, 12);
s.addCell(n);
f = new Formula(6, 2, "F1/2.5");
s.addCell(f);
}

private static void writeImageSheet(WritableSheet s) throws WriteException {
/* Creates Label and writes image to one cell of sheet */
Label l = new Label(0, 0, "Image");
s.addCell(l);
WritableImage wi = new WritableImage(0, 3, 5, 7, new File(
"D:\\eclipseWorkspace1\\Excel\\src\\ad_flag.png"));
s.addImage(wi);

/* Creates Label and writes hyperlink to one cell of sheet */
l = new Label(0, 15, "HYPERLINK");
s.addCell(l);
Formula f = new Formula(1, 15,
"HYPERLINK(\"http://www.google.com\", "
+ "\"Anuj\")");
s.addCell(f);

}

}

readExcel.java
-----------------
import java.io.File;
import java.io.*;
import jxl.*;
import java.util.*;
import jxl.Workbook;
import jxl.read.biff.*;

class readExcel
{
public static void main(String[] args)
{
try
{
String filename = "input.xls";
WorkbookSettings ws = new WorkbookSettings();
ws.setLocale(new Locale("en", "EN"));

Workbook workbook = Workbook.getWorkbook(new File(filename),ws);

Sheet s = workbook.getSheet(0);
Sheet s1 = workbook.getSheet(1);
readDataSheet(s1);
readImageSheet(s);
workbook.close();
}
catch (IOException e)
{
e.printStackTrace();
}
catch (BiffException e)
{
e.printStackTrace();
}

}

private static void readDataSheet(Sheet s)
{
// Find the labeled cell from sheet
LabelCell lc = s.findLabelCell("Date");
System.out.println(lc.getString());

//gets the value of cell at specified column and row
DateCell dc =(DateCell) s.getCell(0,1);
System.out.println(dc.getDate());

lc = s.findLabelCell("Add 2 cells");
System.out.println(lc.getString());

NumberCell c =(NumberCell) s.getCell(4,1);
System.out.println(c.getValue());

c =(NumberCell) s.getCell(4,2);
System.out.println(c.getValue());

NumberFormulaCell nc =(NumberFormulaCell) s.getCell(4,3);
System.out.println(nc.getValue());

}

private static void readImageSheet(Sheet s)
{
LabelCell lc = s.findLabelCell("Image");
System.out.println(lc.getString());

// Gets the image stored in excel document
Image c = s.getDrawing(0);
System.out.println(c.getImageFile());

}
}

String buffer In Java

2010-01-01T00:49:00.000-08:00

import java.io.*;

public class stringBuffer{
public static void main(String[] args) throws Exception{
String str;
try{
str = ", This is the example of SringBuffer class and it's functions.";

//Create a object of StringBuffer class
StringBuffer strbuf = new StringBuffer();
strbuf.append(str);
System.out.println(strbuf);
strbuf.delete(0,str.length());

//append()
strbuf.append("Hello");
strbuf.append("World"); //print HelloWorld
System.out.println(strbuf);

//insert()
strbuf.insert(5,"_Java "); //print Hello_Java World
System.out.println(strbuf);

//reverse()
strbuf.reverse();
System.out.print("Reversed string : ");
System.out.println(strbuf); //print dlroW avaJ_olleH
strbuf.reverse();
System.out.println(strbuf); //print Hello_Java World

//setCharAt()
strbuf.setCharAt(5,' ');
System.out.println(strbuf); //prit Hello Java World

//charAt()
System.out.print("Character at 6th position : ");
System.out.println(strbuf.charAt(6)); //print J

//substring()
System.out.print("Substring from position 3 to 6 : ");
System.out.println(strbuf.substring(3,7)); //print lo J

//deleteCharAt()
strbuf.deleteCharAt(3);
System.out.println(strbuf); //print Helo java World

//capacity()
System.out.print("Capacity of StringBuffer object : ");
System.out.println(strbuf.capacity()); //print 21

//delete() and length()
strbuf.delete(6,strbuf.length());
System.out.println(strbuf); //no anything
}
catch(StringIndexOutOfBoundsException e){
System.out.println(e.getMessage());
}
}
}

Creative way to use Array in Java

2010-01-01T00:46:00.001-08:00

Array Example :

import java.net.MalformedURLException;
import java.net.URL;

public class JavaArray {
public String[] toppings = { ".jpeg", ".jpg", ".png", ".gif", ".ppt",".doc", ".pdf", ".docx", ".psd", ".xls", ".xlsx", ".php" };
boolean flag = false;

public JavaArray() throws MalformedURLException {
String url_test = "www.example.com/a.pdf";
URL url = new URL(url_test);
for (String s : toppings) {
// System.out.println(s);
if (url_test.endsWith(s)) {
flag = false;
break;
} else {
flag = true;
}
}
if (flag) {
System.out.println(url_test);
} else {
System.out.println("exclude this url from crawling");
}

}

public static void main(String[] args) throws MalformedURLException {
new JavaArray();
}
}

Check URL Exists or not In Java

2010-01-01T00:40:00.000-08:00

This will give response as whether url exist or not
import java.net.Authenticator;
import java.net.HttpURLConnection;
import java.net.URL;

public class URLExists {
public static String txtproxyhost = "hostname";
public static String txtproxyport = "port";
public static String txtpuser = "Proxyusername";
public static String txtppassword = "Proxypassword";
public static String s = "webpage link";

public static void main(String args[]) {
try {

URL tt1 = new URL(s);
HttpURLConnection.setFollowRedirects(false);

Authenticator.setDefault(new ProxyAuthenticator(txtpuser,txtppassword.toString()));
System.setProperty("http.proxyHost", txtproxyhost);
System.setProperty("http.proxyPort", txtproxyport);

HttpURLConnection ob1 = (HttpURLConnection) tt1.openConnection();

ob1.setRequestMethod("HEAD");
int c1 = ob1.getResponseCode();
if (c1 == HttpURLConnection.HTTP_OK) {//c1 >= 100 && c1<300
System.out.println("page " + tt1 + " exists");
} else {
System.out.println("page " + tt1 + " doesn't exists");
}
} catch (Exception e1) {
e1.printStackTrace();
}
}
}
class ProxyAuthenticator extends Authenticator {

private String user, password;

public ProxyAuthenticator(String user, String password) {
this.user = user;
this.password = password;
}

protected PasswordAuthentication getPasswordAuthentication() {
return new PasswordAuthentication(user, password.toCharArray());
}
}