The Phone Book Bean Example

This is an example of a JSP-page calling an Enity Bean that uses annotations. The result looks like this:
The primary purpose of the example is to provide a very simple demonstration of an EJB Entity bean. It is not intended to be a complete example or one that could be used as a template for creating your own EJB Entity bean. This is an example using Geronimo 2.1, Java 1.5 and EJB 3.0.

Application Contents

First, let us take a look at the PhoneBook Entity Bean that represents a table in the database. Each instance of PhoneBook is a record of the table.
PhoneBook.java uses the

@Entity annotation to mark this class as an Entity Bean
@Table annotation to map the table name that is being represented by the Entity Bean.
@Id annotation to specify the primary key of the table.

And, as usual there is an empty constructor for the Entity Bean

PhoneBook.java

package org.apache.geronimo.samples.myphonebookpak;

import java.io.Serializable;

import javax.persistence.Id;
import javax.persistence.Entity;
import javax.persistence.Table;

@Entity
@Table(name = "phonebook")
public class PhoneBook implements Serializable {

	private String number;
	private String name;

	public PhoneBook() {

	}

	public PhoneBook(String name, String number) {
		this.name = name;
		this.number = number;
	}

	@Id
	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getNumber() {
		return number;
	}

	public void setNumber(String number) {
		this.number = number;
	}
}

MyPhonebookLocal.java is the business interface that drives the above mentioned Entity Bean.

MyPhonebookLocal.java

package org.apache.geronimo.samples.myphonebookpak;

import org.apache.geronimo.samples.myphonebookpak.PhoneBook;

public interface MyPhonebookLocal {
	public PhoneBook findByPrimaryKey(String name);
}

MyPhonebookBean.java is where the implementation of the local (and if there is, a the remote) interface exists. To explain what the annotations in this Stateless Session Bean means I will enumerate them:

@Stateless - tells Geronimo that this is a stateless session bean
@PersistenceUnit - tells Geronimo to retrieve a persistence unit defined in the persistence.xml and place it in the EntityManagerFactory

Note that PersistenceContext is used when you are directly obtaining a EntityManager. For an EntityManagerFactory use PersistenceUnit.

MyPhonebookBean.java

package org.apache.geronimo.samples.myphonebookpak;

import javax.ejb.Stateless;
import javax.persistence.PersistenceUnit;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;

import org.apache.geronimo.samples.myphonebookpak.PhoneBook;

@Stateless
public class MyPhonebookBean implements MyPhonebookLocal {

	@PersistenceUnit(unitName="PhonePU")
	protected EntityManagerFactory emf;

	public MyPhonebookBean() {

	}

	public PhoneBook findByPrimaryKey(String name) {
		EntityManager em = emf.createEntityManager();

		PhoneBook phonebook = (PhoneBook)em.find(PhoneBook.class, name);

		em.close();

		return phonebook;
	}
}

index.jsp is the JSP page that uses the EJB to access the database.

index.jsp

<%@ page contentType="text/html" import="javax.naming.Context, javax.naming.InitialContext " %>
<%@ page import="org.apache.geronimo.samples.myphonebookpak.MyPhonebookLocal" %>
<%@ page import="org.apache.geronimo.samples.myphonebookpak.PhoneBook" %>

<%
    String searchName = "";
    if (request.getParameter("searchname") != null) {
        searchName = request.getParameter("searchname");
    }
%>

<html>
<head><title>Phonebook</title></head>
<body>
<form action="index.jsp">
    <b>Search number</b>:<br>
    Enter name: <input type="text" name="searchname" value="<%=searchName%>">
    <input type="submit" value="Search">
    (Test with <a href="index.jsp?searchname=Joe">Joe</a>)
</form>
<%
    if (!searchName.equals("")) {
        String number = "";
        try {
            Context context = new InitialContext();
            MyPhonebookLocal myPhonebookLocal = (MyPhonebookLocal) context.lookup("java:comp/env/ejb/MyPhonebookBean");
            PhoneBook phonebook = myPhonebookLocal.findByPrimaryKey(searchName);
            if (phonebook != null) {
                number = phonebook.getNumber();
            }
        }
        catch (Exception e) {
            number = e.toString();
        }
        out.println("This is the number returned from the EJB when searching for '" + searchName + "' : " + number);
    }
%>

</body>
</html>

Deployment Plans

persistence.xml will specify the name of the PersistenceUnit. This name is used when referencing for the EntityManagerFactory. I have denoted it as PhonePU. I added an extra property called SynchronizeMappings so that the data in the database will not be overwritten.

persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.0"
             xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
    <persistence-unit name="PhonePU">
        <description>Phone Book</description>
        <provider>org.apache.openjpa.persistence.PersistenceProviderImpl</provider>
        <jta-data-source>SampleTxDatasource</jta-data-source>
        <non-jta-data-source>SampleNoTxDatasource</non-jta-data-source>
        <class>org.apache.geronimo.samples.myphonebookpak.PhoneBook</class>
        <properties>
            <property name="openjpa.jdbc.SynchronizeMappings" value="false"/>
        </properties>
    </persistence-unit>
</persistence>

Deployment Plan for the Application

plan.xml is generated by building the sample and can be found under ./myphonebook-jetty/target/resources/META-INF/plan.xml to deploy on jetty or ./myphonebook-tomcat/target/resources/META-INF/plan.xml to deploy on tomcat. Shown below is the deployment plan for tomcat.

plan.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--Licensed to the Apache Software Foundation (ASF) under one
    or more contributor license agreements.  See the NOTICE file
    distributed with this work for additional information
    regarding copyright ownership.  The ASF licenses this file
    to you under the Apache License, Version 2.0 (the
    "License"); you may not use this file except in compliance
    with the License.  You may obtain a copy of the License at
    
     http://www.apache.org/licenses/LICENSE-2.0
    
    Unless required by applicable law or agreed to in writing,
    software distributed under the License is distributed on an
    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    KIND, either express or implied.  See the License for the
    specific language governing permissions and limitations
    under the License.-->
<!--$Rev: 497879 $ $Date: 2007-01-19 12:11:01 -0500 (Fri, 19 Jan 2007) $-->
<application xmlns="http://geronimo.apache.org/xml/ns/j2ee/application-1.2">
  <dep:environment xmlns:dep="http://geronimo.apache.org/xml/ns/deployment-1.2">
    <dep:moduleId>
      <dep:groupId>org.apache.geronimo.samples</dep:groupId>
      <dep:artifactId>myphonebook-tomcat</dep:artifactId>
      <dep:version>2.1-SNAPSHOT</dep:version>
      <dep:type>car</dep:type>
    </dep:moduleId>
    <dep:dependencies>
      <dep:dependency>
        <dep:groupId>org.apache.geronimo.samples</dep:groupId>
        <dep:artifactId>sample-datasource</dep:artifactId>
        <dep:version>2.1-SNAPSHOT</dep:version>
        <dep:type>car</dep:type>
      </dep:dependency>
      <dep:dependency>
        <dep:groupId>org.apache.geronimo.configs</dep:groupId>
        <dep:artifactId>jasper</dep:artifactId>
        <dep:version>2.1</dep:version>
        <dep:type>car</dep:type>
      </dep:dependency>
      <dep:dependency>
        <dep:groupId>org.apache.geronimo.configs</dep:groupId>
        <dep:artifactId>tomcat6</dep:artifactId>
        <dep:version>2.1</dep:version>
        <dep:type>car</dep:type>
      </dep:dependency>
      <dep:dependency>
        <dep:groupId>org.apache.geronimo.configs</dep:groupId>
        <dep:artifactId>openejb</dep:artifactId>
        <dep:version>2.1</dep:version>
        <dep:type>car</dep:type>
      </dep:dependency>
    </dep:dependencies>
    <dep:hidden-classes/>
    <dep:non-overridable-classes/>
  </dep:environment>
  <gbean name="DBInitialization" class="org.apache.geronimo.connector.DatabaseInitializationGBean">
    <!--<attribute name="testSQL">select * from phonebook</attribute>-->
    <attribute name="path">PhoneBook.sql</attribute>
    <reference name="DataSource">
      <name>SampleTxDatasource</name>
    </reference>
  </gbean>
</application>

Configuring, Building, and Deploying the Application

Source Code

You can checkout the source code of this sample from SVN:

svn checkout http://svn.apache.org/repos/asf/geronimo/samples/trunk/samples/myphonebook

Creating and Populating Database

The datasource necessary for this example can be installed using the sample-datasource plugin. Use the administration console to first install this plugin. When you deploy the sample application the necessary database table and entries will be created.

Building

Use a command prompt to navigate into the myphonebook directory and just give mvn install followed by mvn site command to build. It will create the myphonebook-ear-2.0-SNAPSHOT.ear under the myphonebook folder. Now, you are ready to deploy myphonebook application in the Geronimo Application server.

Deploying the Application

Deploying sample application is pretty straight forward as we are going to use the Geronimo Console.

Scroll down to Deploy New from the Console Navigation panel.
Load myphonebook-ear-2.1-SNAPSHOT.ear from ./myphonebook-ear/target/ in to the Archive input box.
Load plan.xml from ./myphonebook-jetty/target/resources/META-INF/ or ./myphonebook-tomcat/target/resources/META-INF/ depending on the target server (jetty or tomcat).
Press Install button to deploy application in the server.

MyPhoneBook Web Application

To test the sample web application open a browser and type http://localhost:8080/myphonebook.

Child pages

myphonebook - Very Simple Entity EJB Example