相关疑难解决方法(0)

好的,我阅读了一些文章/示例如何在单例中编写实体管理器工厂.

其中一个对我来说最容易理解:

http://javanotepad.blogspot.com/2007/05/jpa-entitymanagerfactory-in-web.html

我了解到EntityManagerFactory(EMF)应该只在应用程序范围内创建一次.

并确保在使用后关闭EMF(？)

所以我编写了EMF helper类来使用的业务方法:

public class EmProvider {

    private static final String DB_PU = "KogaAlphaPU";

    public static final boolean DEBUG = true;

    private static final EmProvider singleton = new EmProvider();

    private EntityManagerFactory emf;

    private EmProvider() {}

    public static EmProvider getInstance() {
        return singleton;
    }


    public EntityManagerFactory getEntityManagerFactory() {
        if(emf == null) {
            emf = Persistence.createEntityManagerFactory(DB_PU);
        }
        if(DEBUG) {
            System.out.println("factory created on: " + new Date());
        }
        return emf;
    }

    public void closeEmf() {
        if(emf.isOpen() || emf …

我正在使用JSF2和Pure JPA2.但问题出在entityManager上,

@PersistenceContext
private EntityManager entityManager;

这里entityManager没有被注入并且总是为null.有人可以帮我解决我的代码中出了什么问题.

这是我的配置.

User.java

    @Entity
    @Table(name="USER")
    public class User {

        private int id;
        private String name;
        private String surname;

        @Id
        @SequenceGenerator(name="user_id_seq_gen", sequenceName="USER_ID_GEN_SEQ", allocationSize=1)
        @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="user_id_seq_gen")
        @Column(name="ID", unique = true, nullable = false)
        public int getId() {
            return id;
        }

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

        @Column(name="NAME", unique = true, nullable = false)
        public String getName() {
            return name;
        }

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

        @Column(name="SURNAME", unique = true, …

我使用Eclipse Indigo开发了一个使用Glassfish 3 Open Source的JSF 2项目,这在我的计算机上,然后在我的EC2实例中,在Amazon AWS中,对于Glassfish,我创建了一个JDBC连接池,用于我的JPA实体管理器.

本地我的项目工作得非常好,但是当我部署项目并尝试执行相同的表单时,它会从运行GlassFIsh的同一实例EC2中运行的数据库中获取一些值.

我收到此消息:

serverError:class javax.faces.el.E​​valuationException

我正在寻找它,但到目前为止我找不到任何东西.

有什么配置我应该为它起作用吗？

编辑:

这是堆栈跟踪:

javax.faces.FacesException: #{reportc.generateReport}: javax.ejb.EJBException
        at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:118)
        at javax.faces.component.UICommand.broadcast(UICommand.java:315)
        at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:794)
        at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1259)
        at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
        at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
        at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
        at javax.faces.webapp.FacesServlet.service(FacesServlet.java:593)
        at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1539)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
        at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
        at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
        at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:98)
        at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:91)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:162)
        at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:330)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
        at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:174)
        at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:828)
        at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:725)
        at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1019)
        at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:225)
        at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
        at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
        at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
        at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
        at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
        at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
        at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
        at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532) …