using jsp and openjpa....

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Hey i have just been trying to get openjpa and jsp to work.... and i seem to
get some errors.... iam using eclipse for this and running it on tomcat 6.0

Greeeting.java
package foo;

import java.io.Serializable;
import javax.persistence.Basic;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

@Entity
public class Greeting implements Serializable {
@Id @GeneratedValue private int id;
@Basic private String message;
@Basic private String language;

public Greeting() {}
public Greeting(String message, String language) {
this.message = message;
this.language = language;
}

public String toString() {
return "Greeting id=" + id + ", message=" + message + ", language=" +
language;
}
}

HelloWorld.java
package foo;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

persistence.xml
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="1.0" 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_1_0.xsd">
<persistence-unit name="projectjpa">
<class>foo.Greeting</class>
<properties>


<property name="openjpa.ConnectionURL"
value="jdbc:mysql://localhost:3306/greeting"/>
<property name="openjpa.ConnectionDriverName"
value="com.mysql.jdbc.Driver"/>
<property name="openjpa.ConnectionUserName"
value="root"/>
<property name="openjpa.ConnectionPassword"
value="admin"/>
<property name="openjpa.jdbc.SynchronizeMappings"
value="buildSchema(SchemaAction='dropDB,add')"/>
</properties>
</persistence-unit>
</persistence>

open.jsp
<%@(protected)"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<%@(protected)"%>
<%@(protected)"%>
<%@(protected)" %>
<%@(protected)"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<%
final EntityManagerFactory emf;
final EntityManager em;
final String PERSISTENCE_UNIT_NAME = "projectjpa";

emf = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT_NAME);
em = emf.createEntityManager();
////////////////////////

em.getTransaction().begin();
Greeting g_en = new Greeting("hello world", "en");
Greeting g_es = new Greeting("hola, mundo", "es");
Greeting[] greetings = new Greeting[]{g_en, g_es};
for(Greeting g : greetings) {
em.persist(g);
}
em.getTransaction().commit();
///////////////////

Greeting g = (Greeting) em.createQuery(
"select g from Greeting g where g.language = :language")
.setParameter("language", "en").getSingleResult();
out.println("Query returned: " + g);
////////////////////////////////////
em.close();
emf.close();

%>

</body>
</html>

Errors...
org.apache.jasper.JasperException: An exception occurred processing JSP page
/open.jsp at line 21

18:
19:
20: emf = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT_NAME);
21: em = emf.createEntityManager();
22: ////////////////////////
23:
24: em.getTransaction().begin();

Stacktrace:

org.apache.jasper.servlet.JspServletWrapper.handleJspException (JspServletWrapper.java:505)

org.apache.jasper.servlet.JspServletWrapper.service (JspServletWrapper.java:416)
org.apache.jasper.servlet.JspServlet.serviceJspFile (JspServlet.java:337)
org.apache.jasper.servlet.JspServlet.service (JspServlet.java:266)
javax.servlet.http.HttpServlet.service (HttpServlet.java:803)

org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:390)

root cause

java.lang.NullPointerException
org.apache.jsp.open_jsp._jspService(open_jsp.java:76)
org.apache.jasper.runtime.HttpJspBase.service (HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service (HttpServlet.java:803)

org.apache.jasper.servlet.JspServletWrapper.service (JspServletWrapper.java:374)
org.apache.jasper.servlet.JspServlet.serviceJspFile (JspServlet.java:337)
org.apache.jasper.servlet.JspServlet.service (JspServlet.java:266)
javax.servlet.http.HttpServlet.service (HttpServlet.java:803)

org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:390)

note The full stack trace of the root cause is available in the Apache
Tomcat/6.0.16 logs.
--
Sent from the OpenJPA Users mailing list archive at Nabble.com.

using jsp and openjpa....

Anish

2008-08-01