用guice的aop，在interceptor中注入dao，报错

[fejjsong]

 install(new JpaPersistModule("Default"));
 bind(JPAInitializer.class).asEagerSingleton();

public class IntegrationModule extends AbstractModule {
    @Override
    protected void configure() {
        bind(ISubscriberDAO.class).to(JPASubscriberDAO.class);
        IntegrationInterceptor integration = new IntegrationInterceptor();
        requestInjection(integration);
        bindInterceptor(Matchers.subclassesOf(AbstractRestService.class), Matchers.annotatedWith(Integration.class), integration);
    }
}

public class IntegrationInterceptor implements MethodInterceptor {
    @Inject
    private ISubscriberDAO dao;

    @Override
    public Object invoke(MethodInvocation methodInvocation) throws Throwable {
        System.out.println(methodInvocation.getMethod().getName());
        dao.getEntityTotalCount(Subscriber.class);
        return null;
    }
}

但是dao并没有注入,报错：
com.google.inject.CreationException: Guice creation errors:<|<|1) Error in custom provider, java.lang.NullPointerException<| while locating com.google.inject.persist.jpa.JpaPersistService<| while locating javax.persistence.EntityManager<| for field at cn.sury.common.core.dao.jpa.JpaBaseDAO.em(JpaBaseDAO.java:23)<| while locating cn.sury.dao.imp.jpa.JPASubscriberDAO<| while locating cn.sury.dao.ISubscriberDAO<| for field at cn.sury.services.integration.IntegrationInterceptor.dao(IntegrationInterceptor.java:18)<| at cn.sury.server.IntegrationModule.configure(IntegrationModule.java:25)<|<|1 error
at com.google.inject.internal.Errors.throwCreationExceptionIfErrorsExist(Errors.java:435)
at com.google.inject.internal.InternalInjectorCreator.injectDynamically(InternalInjectorCreator.java:175)
at com.google.inject.internal.InternalInjectorCreator.build(InternalInjectorCreator.java:109)
at com.google.inject.Guice.createInjector(Guice.java:95)
at com.google.inject.Guice.createInjector(Guice.java:72)
at com.google.inject.Guice.createInjector(Guice.java:62)
at cn.sury.server.AudibleBookServiceServletConfig.getInjector(AudibleBookServiceServletConfig.java:20)
at com.google.inject.servlet.GuiceServletContextListener.contextInitialized(GuiceServletContextListener.java:45)
at org.eclipse.jetty.server.handler.ContextHandler.callContextInitialized(ContextHandler.java:771)
at org.eclipse.jetty.servlet.ServletContextHandler.callContextInitialized(ServletContextHandler.java:411)
at org.eclipse.jetty.server.handler.ContextHandler.startContext(ContextHandler.java:763)
at org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:247)
at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1238)
at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:706)
at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:480)
at org.mortbay.jetty.plugin.JettyWebAppContext.doStart(JettyWebAppContext.java:293)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
at org.eclipse.jetty.server.handler.HandlerCollection.doStart(HandlerCollection.java:229)
at org.eclipse.jetty.server.handler.ContextHandlerCollection.doStart(ContextHandlerCollection.java:172)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
at org.eclipse.jetty.server.handler.HandlerCollection.doStart(HandlerCollection.java:229)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
at org.eclipse.jetty.server.handler.HandlerWrapper.doStart(HandlerWrapper.java:95)
at org.eclipse.jetty.server.Server.doStart(Server.java:277)
at org.mortbay.jetty.plugin.JettyServer.doStart(JettyServer.java:65)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
at org.mortbay.jetty.plugin.AbstractJettyMojo.startJetty(AbstractJettyMojo.java:511)
at org.mortbay.jetty.plugin.AbstractJettyMojo.execute(AbstractJettyMojo.java:364)
at org.mortbay.jetty.plugin.JettyRunMojo.execute(JettyRunMojo.java:516)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)
at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:320)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)
at org.codehaus.classworlds.Launcher.main(Launcher.java:47)
Caused by:
java.lang.NullPointerException


求分析！

[fejjsong]

确切的说，应该是jps的em没有注入，很奇怪

[x3x]

有没有解决方案？

[rawbean]

完美解决方案是：在interceptor中不要直接注入dao，而是注入com.google.inject.Provider，形如：

@Inject
    private Provider<IDao> dao;