EJB3 and JPA step by step tutorial using Eclipse

Here I explain step by step how to create an EJB 3 with JPA application in Eclipse IDE.
This tutorial is for beginners who want to learn steps to create EJB persistence application with Eclipse and Jboss.

Tools used

Eclipse (Galileo)
Jboss-5.1.0.GA
MySQL database

First of all I'll create a database called studentmgt_db. You can use MySQL GUI tool like MySQL Query Browser or MySQL Work Bench to create a database.

Then I'm going to create a datasource. Go to your jboss directory  ..jboss-5.1.0.GA\docs\examples\jca inside that folder there is file called mysql-ds.xml. I copied that file to  ...jboss-5.1.0.GA\server\default\deploy. Then you can add your database details to that file.

mysql-ds.xml

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1. <?xml version="1.0" encoding="UTF-8"?>  
2.   
3. <!-- $Id: mysql-ds.xml 41017 2006-02-07 14:26:14Z acoliver $ -->  
4. <!--  Datasource config for MySQL using 3.0.9 available from:  
5. http://www.mysql.com/downloads/api-jdbc-stable.html  
6. -->  
7.   
8. <datasources>  
9.   <local-tx-datasource>  
10.     <jndi-name>StudentMgtDS</jndi-name>  
11.     <connection-url>jdbc:mysql://localhost:3306/studentmgt_db</connection-url>  
12.     <driver-class>com.mysql.jdbc.Driver</driver-class>  
13.     <user-name>root</user-name>  
14.     <password>123</password>  
15.     <exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLExceptionSorter</exception-sorter-class-name>  
16.     <!-- should only be used on drivers after 3.22.1 with "ping" support  
17.     <valid-connection-checker-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLValidConnectionChecker</valid-connection-checker-class-name>  
18.     -->  
19.     <!-- sql to call when connection is created  
20.     <new-connection-sql>some arbitrary sql</new-connection-sql>  
21.       -->  
22.     <!-- sql to call on an existing pooled connection when it is obtained from pool - MySQLValidConnectionChecker is preferred for newer drivers  
23.     <check-valid-connection-sql>some arbitrary sql</check-valid-connection-sql>  
24.       -->  
25.   
26.     <!-- corresponding type-mapping in the standardjbosscmp-jdbc.xml (optional) -->  
27.     <metadata>  
28.        <type-mapping>mySQL</type-mapping>  
29.     </metadata>  
30.   </local-tx-datasource>  
31. </datasources>  

<?xml version="1.0" encoding="UTF-8"?>

<!-- $Id: mysql-ds.xml 41017 2006-02-07 14:26:14Z acoliver $ -->
<!--  Datasource config for MySQL using 3.0.9 available from:
http://www.mysql.com/downloads/api-jdbc-stable.html
-->

<datasources>
  <local-tx-datasource>
    <jndi-name>StudentMgtDS</jndi-name>
    <connection-url>jdbc:mysql://localhost:3306/studentmgt_db</connection-url>
    <driver-class>com.mysql.jdbc.Driver</driver-class>
    <user-name>root</user-name>
    <password>123</password>
    <exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLExceptionSorter</exception-sorter-class-name>
    <!-- should only be used on drivers after 3.22.1 with "ping" support
    <valid-connection-checker-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLValidConnectionChecker</valid-connection-checker-class-name>
    -->
    <!-- sql to call when connection is created
    <new-connection-sql>some arbitrary sql</new-connection-sql>
      -->
    <!-- sql to call on an existing pooled connection when it is obtained from pool - MySQLValidConnectionChecker is preferred for newer drivers
    <check-valid-connection-sql>some arbitrary sql</check-valid-connection-sql>
      -->

    <!-- corresponding type-mapping in the standardjbosscmp-jdbc.xml (optional) -->
    <metadata>
       <type-mapping>mySQL</type-mapping>
    </metadata>
  </local-tx-datasource>
</datasources>

 Now create EJB project.

Create a new EJB project called StudentManagementEJB. I use JBoss server as application server.

Create a xml file called persistence.xml in META-INF directory.

persistence.xml

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1. <?xml version="1.0" encoding="UTF-8"?>  
2. <persistence version="2.0"  
3.  xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
4.  xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">  
5.  <persistence-unit name="StudentMgtPU"  
6.   transaction-type="JTA">  
7.   <jta-data-source>java:/StudentMgtDS</jta-data-source>  
8.   <properties>  
9.    <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />  
10.    <property name="hibernate.hbm2ddl.auto" value="create" />  
11.   </properties>  
12.  </persistence-unit>  
13. </persistence>  

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0"
 xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
 <persistence-unit name="StudentMgtPU"
  transaction-type="JTA">
  <jta-data-source>java:/StudentMgtDS</jta-data-source>
  <properties>
   <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
   <property name="hibernate.hbm2ddl.auto" value="create" />
  </properties>
 </persistence-unit>
</persistence>

Then we have to create an Entity class. Right click on the project -> New -> Class

•  Entity Class must have @Entity annotaion
•  Must have a public or protected no-arg constructor
•  If it passed as a detached object through a remote interface, Must implement Serializable
•  Must have an id annotated with @Id

I created a entity class called Student.java
 

Student.java

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1. package com.sameera.domain;  
2.   
3. import java.io.Serializable;  
4. import javax.persistence.*;  
5.   
6. @Entity  
7. @Table(name = "student")  
8. public class Student implements Serializable {  
9.   
10.     private static final long serialVersionUID = 1L;  
11.   
12.     @Id  
13.     @GeneratedValue  
14.     @Column(name = "id")  
15.     private Integer id;  
16.     @Column(name = "first_name", length = 100)  
17.     private String firstName;  
18.     @Column(name = "last_name", length = 100)  
19.     private String lastName;  
20.     @Column(name = "email", length = 100)  
21.     private String email;  
22.   
23.     public String getEmail() {  
24.         return email;  
25.     }  
26.   
27.     public void setEmail(String email) {  
28.         this.email = email;  
29.     }  
30.   
31.     public String getFirstName() {  
32.         return firstName;  
33.     }  
34.   
35.     public void setFirstName(String firstName) {  
36.         this.firstName = firstName;  
37.     }  
38.   
39.     public Integer getId() {  
40.         return id;  
41.     }  
42.   
43.     public void setId(Integer id) {  
44.         this.id = id;  
45.     }  
46.   
47.     public String getLastName() {  
48.         return lastName;  
49.     }  
50.   
51.     public void setLastName(String lastName) {  
52.         this.lastName = lastName;  
53.     }  
54. }  

package com.sameera.domain;

import java.io.Serializable;
import javax.persistence.*;

@Entity
@Table(name = "student")
public class Student implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue
    @Column(name = "id")
    private Integer id;
    @Column(name = "first_name", length = 100)
    private String firstName;
    @Column(name = "last_name", length = 100)
    private String lastName;
    @Column(name = "email", length = 100)
    private String email;

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
}

Create session beans.

I create a Stateless session bean with Local interface.

I added business methods and added add student code.

ManageStudentSessionBeanLocal.java

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1. package com.sameera.session;  
2.   
3. import javax.ejb.Local;  
4.   
5. import com.sameera.domain.Student;  
6.   
7. /** 
8.  *  
9.  * @author Sameera Jayasekara 
10.  *  
11.  */  
12. @Local  
13. public interface ManageStudentSessionBeanLocal {  
14.  public boolean addStudent(Student Student);  
15. }  

package com.sameera.session;

import javax.ejb.Local;

import com.sameera.domain.Student;

/**
 * 
 * @author Sameera Jayasekara
 * 
 */
@Local
public interface ManageStudentSessionBeanLocal {
 public boolean addStudent(Student Student);
}

ManageStudentSessionBean.java

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1. package com.sameera.session;  
2.   
3. import javax.ejb.Stateless;  
4. import javax.persistence.EntityManager;  
5. import javax.persistence.PersistenceContext;  
6.   
7. import com.sameera.domain.Student;  
8.   
9. /** 
10.  * Session Bean implementation class ManageStudentSessionBean 
11.  *  
12.  * @author Sameera Jayasekara 
13.  */  
14. @Stateless  
15. public class ManageStudentSessionBean implements ManageStudentSessionBeanLocal {  
16.   
17.  @PersistenceContext  
18.  private EntityManager entityManager;  
19.   
20.  @Override  
21.  public boolean addStudent(Student student) {  
22.   entityManager.persist(student);  
23.   return true;  
24.  }  
25.   
26. }  

package com.sameera.session;

import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

import com.sameera.domain.Student;

/**
 * Session Bean implementation class ManageStudentSessionBean
 * 
 * @author Sameera Jayasekara
 */
@Stateless
public class ManageStudentSessionBean implements ManageStudentSessionBeanLocal {

 @PersistenceContext
 private EntityManager entityManager;

 @Override
 public boolean addStudent(Student student) {
  entityManager.persist(student);
  return true;
 }

}

Run EJB application on Jboss server.

See the server console JNDI bindings.

 Now see the database. Student table is created.

Now start working on web application.
File -> New -> Dynamic Web Project

Go next Select 'Generate web.xml deployment descriptor' and finish.

Right click on web content and create a new jsp called index.jsp.

index.jsp

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1. <%@page contentType="text/html" pageEncoding="UTF-8"%>  
2. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"  
3.     "http://www.w3.org/TR/html4/loose.dtd">  
4.   
5. <html>  
6.     <head>  
7.         <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">  
8.         <title>EJB3 JPA Jboss - codesstore.blogspot.com</title>  
9.     </head>  
10.     <body>  
11.   
12.         <form action="ManageStudentServlet" method="POST">  
13.   
14.             <table border="0" width="100%">  
15.                 <tr>  
16.                     <td colspan="3">  ${message}</td>  
17.                 </tr>  
18.                 <tr>  
19.                     <td>First Name</td>  
20.                     <td>:</td>  
21.                     <td><input type="text" name="fname" value="" /></td>  
22.                 </tr>  
23.                 <tr>  
24.                     <td>Last Name</td>  
25.                     <td>:</td>  
26.                     <td><input type="text" name="lname" value="" /></td>  
27.                 </tr>  
28.                 <tr>  
29.                     <td>Email</td>  
30.                     <td>:</td>  
31.                     <td><input type="text" name="email" value="" /></td>  
32.                 </tr>  
33.                 <tr>  
34.                     <td></td>  
35.                     <td></td>  
36.                     <td><input type="submit" value="Add" name="Add" /></td>  
37.                 </tr>  
38.             </table>  
39.   
40.         </form>  
41.   
42.     </body>  
43. </html>  

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
    "http://www.w3.org/TR/html4/loose.dtd">

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>EJB3 JPA Jboss - codesstore.blogspot.com</title>
    </head>
    <body>

        <form action="ManageStudentServlet" method="POST">

            <table border="0" width="100%">
                <tr>
                    <td colspan="3">  ${message}</td>
                </tr>
                <tr>
                    <td>First Name</td>
                    <td>:</td>
                    <td><input type="text" name="fname" value="" /></td>
                </tr>
                <tr>
                    <td>Last Name</td>
                    <td>:</td>
                    <td><input type="text" name="lname" value="" /></td>
                </tr>
                <tr>
                    <td>Email</td>
                    <td>:</td>
                    <td><input type="text" name="email" value="" /></td>
                </tr>
                <tr>
                    <td></td>
                    <td></td>
                    <td><input type="submit" value="Add" name="Add" /></td>
                </tr>
            </table>

        </form>

    </body>
</html>

Create  a servlet to handle the request.
File -> New -> Servlet

Before calling Enterprise beans we have to add the ejb project to build path.

 Go to projects tab and add StudentManagementEJB project.

ManageStudentServlet.java

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1. package com.sameera.controller;  
2.   
3. import java.io.IOException;  
4.   
5. import javax.naming.Context;  
6. import javax.naming.InitialContext;  
7. import javax.naming.NamingException;  
8. import javax.servlet.RequestDispatcher;  
9. import javax.servlet.ServletConfig;  
10. import javax.servlet.ServletException;  
11. import javax.servlet.http.HttpServlet;  
12. import javax.servlet.http.HttpServletRequest;  
13. import javax.servlet.http.HttpServletResponse;  
14.   
15. import com.sameera.domain.Student;  
16. import com.sameera.session.ManageStudentSessionBeanLocal;  
17.   
18. /** 
19.  *  
20.  * @author Sameera Jayasekara 
21.  *  
22.  */  
23. public class ManageStudentServlet extends HttpServlet {  
24.   
25.  private static final long serialVersionUID = 1L;  
26.  private ManageStudentSessionBeanLocal manageStudentSessionBeanLocal;  
27.   
28.  public void init(ServletConfig config) throws ServletException {  
29.   
30.   super.init(config);  
31.   try {  
32.   
33.    Context context = new InitialContext();  
34.    manageStudentSessionBeanLocal = (ManageStudentSessionBeanLocal) context  
35.      .lookup("ManageStudentSessionBean/local");  
36.   
37.   } catch (NamingException e) {  
38.    e.printStackTrace();  
39.   }  
40.   
41.  }  
42.   
43.  protected void doGet(HttpServletRequest request,  
44.    HttpServletResponse response) throws ServletException, IOException {  
45.   
46.  }  
47.   
48.  protected void doPost(HttpServletRequest request,  
49.    HttpServletResponse response) throws ServletException, IOException {  
50.   
51.   String message = "";  
52.   
53.   String firstName = request.getParameter("fname");  
54.   String lastName = request.getParameter("lname");  
55.   String email = request.getParameter("email");  
56.   
57.   Student student = new Student();  
58.   student.setFirstName(firstName);  
59.   student.setLastName(lastName);  
60.   student.setEmail(email);  
61.   
62.   if (manageStudentSessionBeanLocal.addStudent(student)) {  
63.    message = "Student Successfuly Added";  
64.   } else {  
65.    message = "Student Adding Failed";  
66.   }  
67.   
68.   request.setAttribute("message", message);  
69.   RequestDispatcher rd = request.getRequestDispatcher("index.jsp");  
70.   rd.forward(request, response);  
71.   
72.  }  
73.   
74. }  

package com.sameera.controller;

import java.io.IOException;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.sameera.domain.Student;
import com.sameera.session.ManageStudentSessionBeanLocal;

/**
 * 
 * @author Sameera Jayasekara
 * 
 */
public class ManageStudentServlet extends HttpServlet {

 private static final long serialVersionUID = 1L;
 private ManageStudentSessionBeanLocal manageStudentSessionBeanLocal;

 public void init(ServletConfig config) throws ServletException {

  super.init(config);
  try {

   Context context = new InitialContext();
   manageStudentSessionBeanLocal = (ManageStudentSessionBeanLocal) context
     .lookup("ManageStudentSessionBean/local");

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

 }

 protected void doGet(HttpServletRequest request,
   HttpServletResponse response) throws ServletException, IOException {

 }

 protected void doPost(HttpServletRequest request,
   HttpServletResponse response) throws ServletException, IOException {

  String message = "";

  String firstName = request.getParameter("fname");
  String lastName = request.getParameter("lname");
  String email = request.getParameter("email");

  Student student = new Student();
  student.setFirstName(firstName);
  student.setLastName(lastName);
  student.setEmail(email);

  if (manageStudentSessionBeanLocal.addStudent(student)) {
   message = "Student Successfuly Added";
  } else {
   message = "Student Adding Failed";
  }

  request.setAttribute("message", message);
  RequestDispatcher rd = request.getRequestDispatcher("index.jsp");
  rd.forward(request, response);

 }

}

I looked up ManageStudentSessionBean/local. You can see server console to find JNDI bindings(see image given above)

You can use @EJB annotaions to dependancy injection in a servlet but I tried it with JBoss that didn't work.Then I used @EJB(mappedName="Test"), @EJB with mappedName attribute( @Stateless(mappedName="Test") also used).Then it worked with remote interface. But I prefer JNDI lookup.

web.xml configuration file looks like this.

web.xml

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1. <?xml version="1.0" encoding="UTF-8"?>  
2. <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">  
3.   <display-name>StudentManagementWeb</display-name>  
4.   <welcome-file-list>  
5.     <welcome-file>index.jsp</welcome-file>  
6.   </welcome-file-list>  
7.   <servlet>  
8.     <description></description>  
9.     <display-name>ManageStudentServlet</display-name>  
10.     <servlet-name>ManageStudentServlet</servlet-name>  
11.     <servlet-class>com.sameera.controller.ManageStudentServlet</servlet-class>  
12.   </servlet>  
13.   <servlet-mapping>  
14.     <servlet-name>ManageStudentServlet</servlet-name>  
15.     <url-pattern>/ManageStudentServlet</url-pattern>  
16.   </servlet-mapping>  
17. </web-app>  

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>StudentManagementWeb</display-name>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  <servlet>
    <description></description>
    <display-name>ManageStudentServlet</display-name>
    <servlet-name>ManageStudentServlet</servlet-name>
    <servlet-class>com.sameera.controller.ManageStudentServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>ManageStudentServlet</servlet-name>
    <url-pattern>/ManageStudentServlet</url-pattern>
  </servlet-mapping>
</web-app>

Now You can run the web application.

 Check the database data will be added.

Project structure in Eclipse

Note : I put mysql-connector-java-5.1.5-bin.jar to ...jboss-5.1.0.GA\server\default\lib