TransactionRequiredException：Jersey Guice JPA没有进行任何交易

使用Guice 3.0，遵循本教程：https://code.google.com/p/google-guice/wiki/JPA

GuiceModule类：

public class GuiceModule extends ServletModule {

@Override
protected void configureServlets() {
  // start the service
  bind(JPAInitializer.class).asEagerSingleton();

  // PersistFilter
  filter("/*").through(PersistFilter.class);

  // jpa + guice
  install(new JpaPersistModule("drone-cloud"));

  // bindings
  bind(UserService.class).to(UserServiceImpl.class);
  bind(TwoFactorAuthenticator.class).to(GoogleAuthenticator.class);
  bind(ImageQueue.class).asEagerSingleton();
  bind(DroneCloudServerHandler.class).asEagerSingleton();
 }
}

JPAInitializer.class

import javax.inject.Inject;
import com.google.inject.persist.PersistService;

public class JPAInitializer {
   @Inject
   JPAInitializer(PersistService service) {
      service.start();
   }
}

控制器类：

@Consumes(MediaType.APPLICATION_JSON)
@Path("/mission")
public class MissionController {

   @Inject
   Provider<EntityManager> _em;

   @Path("/new")
   @POST
   @Transactional
   public String newMission(SimpleMission mission) {

      _em.get().persist(mission);
      _em.get().flush();
      _em.get().close();

      return "{ \"mission_id\": \"" + mission.getId() + "\" }";
   }
}

和堆栈跟踪：

javax.persistence.TransactionRequiredException：org.hibernate.jpa.spi.AbstractEntityManagerImpl.checkTransactionNeeded（AbstractEntityManagerImpl.java:1171）org.hibernate.jpa.spi.AbstractEntityManagerImpl.flush（AbstractEntityManagerImpl.java:1332）中没有正在进行的事务正在进行中com.drone.mission.controller.MissionController.newMission（MissionController.java:37）在sun.reflect.NativeMethodAccessorImpl.invoke0（本机方法）在sun.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:57）在sun.reflect . DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）位于org.glassfish.jersey.server.model.internal.ResourceMethodInvocationHandlerFactory $ 1.invoke的java.lang.reflect.Method.invoke（Method.java:606）中（ResourceMethodInvocationHandlerFactory.java:81 ）在org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher $ 1.run（AbstractJavaResourceMethodDispatcher.java:151）在org.glassfish.jersey.server.model.internal.AbstractJavaResource位于org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider $ TypeOutInvoker.doDispatch（JavaResourceMethodDispatcherProvider.java:195）的orD.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher上的MethodDispatcher.invoke（AbstractJavaResourceMethodDispatcher.java:171） . 发送（AbstractJavaResourceMethodDispatcher.java:104）org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke（ResourceMethodInvoker.java:406）org.glassfish.jersey.server.model.ResourceMethodInvoker.apply（ResourceMethodInvoker.java:350）在org.glassfish.jersey.server.model.ResourceMethodInvoker.apply（ResourceMethodInvoker.java:106）在org.glassfish.jersey.server.ServerRuntime $ 1.run（ServerRuntime.java:259）在org.glassfish.jersey.internal . 错误$ 1.call（Errors.java:271）org.glassfish.jersey.internal.Errors $ 1.call（Errors.java:267）org.glassfish.jersey.internal.Errors.process（Errors.java:315） org.glfish.jersey.internal.Errors.process（Errors.java:297）org.gl位于org.glassfish.jersey.process.run的现场org.glassfish.jersey.process.internal.RequestScope.runInScope（RequestScope.java:320）中的assfish.jersey.internal.Errors.process（Errors.java:267）（ ServerRuntime.java:236）在org.glassfish.jersey.server.ApplicationHandler.handle（ApplicationHandler.java:1028）在org.glassfish.jersey.servlet.WebComponent.service（WebComponent.java:373）在org.glassfish.jersey .servlet.ServletContainer.service（ServletContainer.java:381）在org.glassfish.jersey.servlet.ServletContainer.service（ServletContainer.java:344）在org.glassfish.jersey.servlet.ServletContainer.service（ServletContainer.java:219 ）org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:303）org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:208）org.apache.tomcat.websocket.server . WsFilter.doFilter（WsFilter.java:52）在org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java： 241）org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:208）org.apache.catalina.core.StandardWrapperValve.invoke（StandardWrapperValve.java:220）at org.apache.catalina.core.StandardContextValve .__在org.apache.catalina.core.StandardContextValve.invoke（StandardContextValve.java）在org.apache.catalina.authenticator.AuthenticatorBase.invoke（AuthenticatorBase.java:501）调用（StandardContextValve.java:122）在org.apache . catalina.core.StandardHostValve .__在org.apache.catalina.core.StandardHostValve.invoke（StandardHostValve.java）的org.apache.catalina.valves.ErrorReportValve.invoke（ErrorReportValve.java:98）中调用（StandardHostValve.java:170）在org.apache.catalina.valves.AccessLogValve.invoke（AccessLogValve.java:950）在org.apache.catalina.core.StandardEngineValve.invoke（StandardEngineValve.java:116）在org.apache.catalina.connector.CoyoteAdapter.service （CoyoteAdapter.java:408）org.apache.coyote.http11.AbstractHttp11Processor.process（AbstractHttp） 11Processor.java:1040）在org.apache.coyote.AbstractProtocol $ AbstractConnectionHandler.process（AbstractProtocol.java:607）在org.apache.tomcat.util.net.JIoEndpoint $ SocketProcessor.run（JIoEndpoint.java:313）在java.util.concurrent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1145）java.lang.ThreadPoolExecutor $ Worker.run（ThreadPoolExecutor.java:615）java.lang.Thread.run（Thread.java:744）

我究竟做错了什么？

谢谢