[Persistence, JBoss/CMP, Hibernate, Database] - NPE with EntityManagerFactory
by Hellek
I always get a NullPointerException with this:
public class Servlet1 extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet {
|
| @PersistenceUnit(name="EJBProject1")
| EntityManagerFactory emf;
|
| protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
| response.setContentType("text/html");
| response.setHeader("Pragma", "No-cache");
| response.setDateHeader("Expires", 0);
| response.setHeader("Cache-Control", "no-cache");
|
| EntityManager em1 = emf.createEntityManager();
| Query query1 = em1.createQuery("select b from benutzer b");
| List users = query1.getResultList();
| PrintWriter writer = response.getWriter();
|
| for (Iterator iterator = users.iterator(); iterator.hasNext();) {
| Benutzer benutzer = (Benutzer) iterator.next();
| writer.print(benutzer.getName());
| }
| writer.flush();
| }
| }
I failed to figure out whats going wrong for hours, had my problems with some other issues too. But unlike those, I did not manage to fix this one.
The exception:
03:29:09,125 ERROR [[Servlet1]] Servlet.service() for servlet Servlet1 threw exception
| java.lang.NullPointerException
| at com.Servlet1.doGet(Servlet1.java:46)
| at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
| at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
| at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
| at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
| at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
| at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
| at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
| at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
| at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
| at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:179)
| at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:84)
| at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
| at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
| at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:156)
| at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
| at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:241)
| at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
| at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:580)
| at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
| at java.lang.Thread.run(Unknown Source)
|
I use JBoss 4.2.0 and Eclipse 3.3M6 with M6 WTP.
Here is the 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="EJBProject1">
| <provider>org.hibernate.ejb.HibernatePersistence</provider>
| <jta-data-source>java:TestDS</jta-data-source>
| <class>com.Benutzer</class>
| <properties>
| <property name="hibernate.dialect"
| value="org.hibernate.dialect.MySQLDialect" />
| <property name="hibernate.transaction.manager_lookup_class"
| value="org.hibernate.transaction.JBossTransactionManagerLookup"/>
|
| </properties>
| </persistence-unit>
| </persistence>
|
The Datastore-Definition (I put the driver in place and it gets loaded successfully according to the logs)
<local-tx-datasource>
| <jndi-name>TestDS</jndi-name>
| <connection-url>jdbc:mysql://...:3306/test</connection-url>
| <driver-class>com.mysql.jdbc.Driver</driver-class>
| <user-name>...</user-name>
| <password>...</password>
| <min-pool-size>5</min-pool-size>
| <max-pool-size>20</max-pool-size>
|
| <metadata>
| <type-mapping>mySQL</type-mapping>
| </metadata>
| </local-tx-datasource>
By the way, I came across this problem while following this tutorial: http://www.eclipse.org/webtools/jst/components/j2ee/scenarios/jee5_applic...
I want to do what is done there, with JBoss, Hibernate and a MySQL Server
Here you can find my project files: http://hellekalek.com/diverses/workspace.zip
I really hope somebody can tell me what I am doing wrong. I lost all hope. Its just such a small tutorial that I want to follow, it can't be that difficult ... I thought. (of course its a little different because they don't use JBoss, but its really not a big project)
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19 years, 1 month
[EJB 3.0] - any idea to inject a ejb to tapestry?
by phoenix.zhp
hi, I use tapestry as web tier and want get a slsb in this tier. this is my code:
public abstract class Home extends BasePage {
// @EJB
// Calculator bean;
public String getResult() {
// Double message = bean.calculate(11, 22, 0.08, 44);
// return message.toString();
InitialContext ctx = null;
Calculator bean = null;
try {
ctx = new InitialContext();
bean = (Calculator) ctx
.lookup("ejb3TapestryJboss/CalculatorBean/local");
} catch (NamingException e) {
e.printStackTrace();
}
Double message = bean.calculate(22, 22, 0.08, 22);
return "ok! " + message.toString();
}
}
When I use JNDI's lookup, as showed above, it works. But when I want to inject a slsb to this page, as the commented code showed, it get nothing. No bean is injected. do I misues this annotation? and how can I inject a bean to tapestry? or I can only do this in servlet? By the way, I use jbossAs 5 beta2 as the server.
Thanks for your help in advance.
View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4046342#4046342
Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4046342
19 years, 1 month
[Installation, Configuration & Deployment] - any idea to inject a ejb to tapestry?
by phoenix.zhp
hi, I use tapestry as web tier and want get a slsb in this tier. this is my code:
public abstract class Home extends BasePage {
// @EJB
// Calculator bean;
public String getResult() {
// Double message = bean.calculate(11, 22, 0.08, 44);
// return message.toString();
InitialContext ctx = null;
Calculator bean = null;
try {
ctx = new InitialContext();
bean = (Calculator) ctx
.lookup("ejb3TapestryJboss/CalculatorBean/local");
} catch (NamingException e) {
e.printStackTrace();
}
Double message = bean.calculate(22, 22, 0.08, 22);
return "ok! " + message.toString();
}
}
When I use JNDI's lookup, as showed above, it works. But when I want to inject a slsb to this page, as the commented code showed, it get nothing. No bean is injected. do I misues this annotation? and how can I inject a bean to tapestry? or I can only do this in servlet? By the way, I use jbossAs 5 beta2 as the server.
Thanks for your help in advance.
View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4046341#4046341
Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4046341
19 years, 1 month
[JBoss/Spring Integration] - any idea to inject a ejb to tapestry?
by phoenix.zhp
hi, I use tapestry as web tier and want get a slsb in this tier. this is my code:
public abstract class Home extends BasePage {
// @EJB
// Calculator bean;
public String getResult() {
// Double message = bean.calculate(11, 22, 0.08, 44);
// return message.toString();
InitialContext ctx = null;
Calculator bean = null;
try {
ctx = new InitialContext();
bean = (Calculator) ctx
.lookup("ejb3TapestryJboss/CalculatorBean/local");
} catch (NamingException e) {
e.printStackTrace();
}
Double message = bean.calculate(22, 22, 0.08, 22);
return "ok! " + message.toString();
}
}
When I use JNDI's lookup, as showed above, it works. But when I want to inject a slsb to this page, as the commented code showed, it get nothing. No bean is injected. do I misues this annotation? and how can I inject a bean to tapestry? or I can only do this in servlet? By the way, I use jbossAs 5 beta2 as the server.
Thanks for your help in advance.
View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4046340#4046340
Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4046340
19 years, 1 month