我最近开始使用Glassfish和boneCP在intellij的想法上使用一个简单的网络应用程序，但有一个我无法理解的错误。我相信我遵循了教程中的所有步骤。
我的模型就像这样
@Entity
public class Song implements Serializable {
@Id
private String id;
private String title;
private LocalDate lastPlayed;
private int playCount;
public Song() {
title = "Chant sans titre";
id = generateId(title);
lastPlayed = LocalDate.ofEpochDay(0);
playCount = 0;
}
EJB
@Stateless
public class SongDAO {
@PersistenceUnit(unitName = "statisthira_song")
private EntityManager em;
public void create(Song song){
try {
em.persist(song); } catch (Exception e) { e.printStackTrace(); }
}
Servlet
@WebServlet(urlPatterns = "/new-song")
public class NewSongActionBean extends HttpServlet {
@EJB
SongDAO dao;
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
Song song = new Song();
song.setTitle("This is not a Test - Toby Mac");
song.setId(song.generateId(song.getTitle()));
dao.create(song);
this.getServletContext().getRequestDispatcher("/WEB-INF/newsong.jsp").forward(request, response);
}
}
我在META-INF下的persistence.xml文件
<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence" version="2.0"
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_2_0.xsd">
<persistence-unit name="statisthira_song" transaction-type="JTA">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<jta-data-source>jdbc/bonecp_resource</jta-data-source>
<class>statis.hira.model.Song</class>
</persistence-unit>
</persistence>
服务器运行没有任何问题，当我用ping检查jdbc连接池时，它成功。但是当我尝试访问网址＆＃34; / new-song＆＃34;时，我收到此错误消息
HTTP Status 500 - Internal Server Error
type Exception report
message Internal Server Error
description The server encountered an internal error that prevented it from fulfilling this request.
exception javax.ejb.EJBException: javax.ejb.EJBException: javax.ejb.CreateException: Could not create stateless EJB
这里是stacktrace的样本
javax.ejb.EJBException: javax.ejb.EJBException: javax.ejb.CreateException: Could not create stateless EJB
at com.sun.ejb.containers.StatelessSessionContainer._getContext(StatelessSessionContainer.java:435)
at com.sun.ejb.containers.BaseContainer.getContext(BaseContainer.java:2579)
at com.sun.ejb.containers.BaseContainer.preInvoke(BaseContainer.java:1971)
at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:210)
at com.sun.ejb.containers.EJBLocalObjectInvocationHandlerDelegate.invoke(EJBLocalObjectInvocationHandlerDelegate.java:88)
at com.sun.proxy.$Proxy194.create(Unknown Source)
at statis.hira.dao.__EJB31_Generated__SongDAO__Intf____Bean__.create(Unknown Source)
at statis.hira.servlets.NewSongActionBean.doGet(NewSongActionBean.java:26)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:687)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:416)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:283)
at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167)
at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:206)
at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:180)
at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235)
at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:283)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:200)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:132)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:111)
at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:536)
at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571)
at java.lang.Thread.run(Thread.java:745)
Caused by: javax.ejb.EJBException: javax.ejb.CreateException: Could not create stateless EJB
at com.sun.ejb.containers.StatelessSessionContainer$SessionContextFactory.create(StatelessSessionContainer.java:700)
at com.sun.ejb.containers.util.pool.NonBlockingPool.getObject(NonBlockingPool.java:246)
at com.sun.ejb.containers.StatelessSessionContainer._getContext(StatelessSessionContainer.java:430)
... 37 more
Caused by: javax.ejb.CreateException: Could not create stateless EJB
at com.sun.ejb.containers.StatelessSessionContainer.createStatelessEJB(StatelessSessionContainer.java:514)
at com.sun.ejb.containers.StatelessSessionContainer.access$000(StatelessSessionContainer.java:97)
at com.sun.ejb.containers.StatelessSessionContainer$SessionContextFactory.create(StatelessSessionContainer.java:698)
... 39 more
Caused by: java.lang.IllegalStateException: Exception attempting to inject Env-Prop: statis.hira.dao.SongDAO/em@Field-Injectable Resource. Class name = statis.hira.dao.SongDAO Field name=em@java.lang.String@@@ into class statis.hira.dao.SongDAO: Can not set javax.persistence.EntityManager field statis.hira.dao.SongDAO.em to com.sun.enterprise.container.common.impl.EntityManagerFactoryWrapper
at org.glassfish.weld.services.InjectionServicesImpl.aroundInject(InjectionServicesImpl.java:175)
at org.jboss.weld.injection.InjectionContextImpl.run(InjectionContextImpl.java:46)
at org.jboss.weld.injection.producer.DefaultInjector.inject(DefaultInjector.java:73)
at org.jboss.weld.injection.producer.StatelessSessionBeanInjector.inject(StatelessSessionBeanInjector.java:60)
at org.jboss.weld.injection.producer.ejb.SessionBeanInjectionTarget.inject(SessionBeanInjectionTarget.java:140)
at org.glassfish.weld.services.JCDIServiceImpl.injectEJBInstance(JCDIServiceImpl.java:257)
at com.sun.ejb.containers.BaseContainer.injectEjbInstance(BaseContainer.java:1748)
at com.sun.ejb.containers.StatelessSessionContainer.createStatelessEJB(StatelessSessionContainer.java:475)
... 41 more
Caused by: com.sun.enterprise.container.common.spi.util.InjectionException: Exception attempting to inject Env-Prop: statis.hira.dao.SongDAO/em@Field-Injectable Resource. Class name = statis.hira.dao.SongDAO Field name=em@java.lang.String@@@ into class statis.hira.dao.SongDAO: Can not set javax.persistence.EntityManager field statis.hira.dao.SongDAO.em to com.sun.enterprise.container.common.impl.EntityManagerFactoryWrapper
at com.sun.enterprise.container.common.impl.util.InjectionManagerImpl._inject(InjectionManagerImpl.java:740)
at com.sun.enterprise.container.common.impl.util.InjectionManagerImpl.inject(InjectionManagerImpl.java:507)
at com.sun.enterprise.container.common.impl.util.InjectionManagerImpl.injectInstance(InjectionManagerImpl.java:170)
at org.glassfish.weld.services.InjectionServicesImpl.aroundInject(InjectionServicesImpl.java:165)
... 48 more
Caused by: java.lang.IllegalArgumentException: Can not set javax.persistence.EntityManager field statis.hira.dao.SongDAO.em to com.sun.enterprise.container.common.impl.EntityManagerFactoryWrapper
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:167)
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:171)
at sun.reflect.UnsafeObjectFieldAccessorImpl.set(UnsafeObjectFieldAccessorImpl.java:81)
at java.lang.reflect.Field.set(Field.java:764)
at com.sun.enterprise.container.common.impl.util.InjectionManagerImpl._inject(InjectionManagerImpl.java:688)
... 51 more
答案 0 :(得分：4)
你应该从
改变@PersistenceUnit(unitName = "statisthira_song")
到
@PersistenceContext(name= "statisthira_song")
@PersistenceUnit 用于注入EntityManagerFactory， @PersistenceContext 用于注入EntityManager