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:
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 their is an empty constructor for the Entity Bean
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.
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. 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.
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.
<%@ page contentType="text/html" import="org.apache.geronimo.samples.myphonebookpak.*, javax.naming.* " %>
<%
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 for EJB
openejb-jar.xml just specifies the module's information.
<?xml version="1.0" encoding="UTF-8"?> <openejb-jar xmlns="http://www.openejb.org/xml/ns/openejb-jar-2.1" xmlns:nam="http://geronimo.apache.org/xml/ns/naming-1.1" xmlns:pkgen="http://www.openejb.org/xml/ns/pkgen-2.0" xmlns:sec="http://geronimo.apache.org/xml/ns/security-1.1" xmlns:sys="http://geronimo.apache.org/xml/ns/deployment-1.2"> <sys:environment> <sys:moduleId> <sys:groupId>org.apache.geronimo.samples</sys:groupId> <sys:artifactId>MyPhonebookBean</sys:artifactId> <sys:version>1.0</sys:version> <sys:type>car</sys:type> </sys:moduleId> </sys:environment> </openejb-jar>
persistence.xml will specify the name of the PersistenceUnit. This name is used when referencing for the EntityManagerFactory. I have denoted it as PhonePU. For some reason I could not get it to reference with jta-data-source. So the alternative method is to explicitly specify the ConnectionURL, ConnectionDriverName, and ConnectionUserName. I added an extra property called SynchronizeMappings so that the data in the database will not be overwritten.
<?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> <class>org.apache.geronimo.samples.myphonebookpak.PhoneBook</class> <properties> <property name="openjpa.ConnectionURL" value="jdbc:derby:PhoneBookDB" /> <property name="openjpa.ConnectionDriverName" value="org.apache.derby.jdbc.EmbeddedDriver" /> <property name="ConnectionUserName" value="app" /> <property name="openjpa.jdbc.SynchronizeMappings" value="false" /> </properties> </persistence-unit> <!-- <jta-data-source>PhoneBookPool</jta-data-source> <non-jta-data-source>PhoneBookPool</non-jta-data-source> --> </persistence>
Deployment Plans for Web-App
web.xml references the EJB by specifying the package to which the MyPhonebookLocal belongs to.
<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<display-name>MyPhonebookWeb</display-name>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<ejb-local-ref>
<ejb-ref-name>ejb/MyPhonebookBean</ejb-ref-name>
<ejb-ref-type>Entity</ejb-ref-type>
<local>org.apache.geronimo.samples.myphonebookpak.MyPhonebookLocal</local>
</ejb-local-ref>
</web-app>
geronimo-web.xml specifies the module's information and the context-root for the web-app.
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://geronimo.apache.org/xml/ns/j2ee/web-1.1"
xmlns:nam="http://geronimo.apache.org/xml/ns/naming-1.1"
xmlns:sec="http://geronimo.apache.org/xml/ns/security-1.1"
xmlns:sys="http://geronimo.apache.org/xml/ns/deployment-1.1">
<sys:environment>
<sys:moduleId>
<sys:groupId>org.apache.geronimo.samples</sys:groupId>
<sys:artifactId>MyPhonebookWeb</sys:artifactId>
<sys:version>1.0</sys:version>
<sys:type>car</sys:type>
</sys:moduleId>
</sys:environment>
<context-root>/myphonebook</context-root>
</web-app>
Configuring, Building, and Deploying the Application
Download the MyPhoneBook application from the following link:
MyPhoneBook
After decompressing the given file, the myphonebook directory will be created.
Configuring
Configuration of the application consists of creating the database and defining the connection pool to access it.
Creating and Populating Database
After starting Apache Geronimo log into the console and follow the given steps to create the PhoneBookDB.
CREATE TABLE phonebook ( name VARCHAR(255) PRIMARY KEY, number VARCHAR(255) );
INSERT INTO phonebook VALUES ('John', '1234');
INSERT INTO phonebook VALUES ('Joe', '5678');
- Select DB Manager link from the Console Navigation in the left.
- Give the database name as PhoneBookDB and click Create button.
- Select PhoneBookDB to the Use DB field.
- Open PhoneBookDB.sql in the myphonebook directory from a text editor.
- Paste the content PhoneBookDB.sql to the SQL Commands text area and press Run SQL button.
Building
Use a command prompt to navigate into the myphonebook directory and just give mvn clean install command to build. It will create the myphonebook-ear-2.0-SNAPSHOT.ear under the myphonebook/myphonebook-ear/target folder. Now, you are ready to deploy myphonebook application in the Geronimo Application server.
Deploying the Database Pool
- Scroll down to Deploy New from the Console Navigation panel.
- Load tranql-connector-1.3.rar from the lib folder into the Archive input box.
- Load PhoneBookPool.xml into the Plan input box.
- Press Install button to deploy the database pool.
To ensure that the database pool was successfully deployed scroll down to Database Pool and click it.
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-2.0-SNAPSHOT.ear from myphonebook/myphonebook-ear/target folder in to the Archive input box.
- 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
.