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hibernate - EntityManager.createQuery() 抛出 NullPointerException

转载 作者：行者123 更新时间：2023-12-04 16:44:03 24 4
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'我每次都会收到 NullPointerException EntityManager.createQuery()或 EntityManager.createNamedQuery()叫做。

我正在使用 Glassfish 4.0、Hibernate 4.3.5 和 EJB。

我有以下层次结构:

我有 PersistenceContext 和泛型方法的 DaoTemplate

@Singleton
public class DaoTemplate<T extends IdEntityInterface> {
    @PersistenceContext(unitName = "pu_name")
    protected EntityManager em;
    ....
}

具有构造函数的抽象类，因为 bean 不能扩展另一个 bean。 
public abstract class AbstractDaoTemplate<T extends IdEntityInterface> extends    DaoTemplate<T> {

    public AbstractDaoTemplate(Class<T> entityClass) {
        super(entityClass);
    }

}

然后我有道。 
@Singleton
public class SomeDao extends AbstractDaoTemplate<SomeEntity> {

    public SomeDao() {
        super(SomeEntity.class)
    }        

    @TransactionAttribute(TransactionAttributeType.REQUIRES_NEW)
    public List<SomeEntity> someDaoMethod() {
        ...
        em.createQuery("SomeQuery");
        ...   
    }
}

当 someDaoMethod 被调用时，NullPointerException 被抛出在线 em.createQuery("SomeQuery")但是 em不为空。

我也试过调用 em.createQuery("SomeQuery")从调试器窗口，这里是输出: 
Exception occurred in target VM:  
java.lang.NullPointerException: 
    at org.hibernate.engine.transaction.internal.jta.JtaStatusHelper.getStatus(JtaStatusHelper.java:76)
    at org.hibernate.engine.transaction.internal.jta.JtaStatusHelper.isActive(JtaStatusHelper.java:118)
    at org.hibernate.engine.transaction.internal.jta.CMTTransaction.join(CMTTransaction.java:149)
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.joinTransaction(AbstractEntityManagerImpl.java:1602)
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.postInit(AbstractEntityManagerImpl.java:210)
    at org.hibernate.jpa.internal.EntityManagerImpl.<init>(EntityManagerImpl.java:91)
    at org.hibernate.jpa.internal.EntityManagerFactoryImpl.internalCreateEntityManager(EntityManagerFactoryImpl.java:345)
    at org.hibernate.jpa.internal.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:338)
    at com.sun.enterprise.container.common.impl.EntityManagerWrapper._getDelegate(EntityManagerWrapper.java:197)
    at com.sun.enterprise.container.common.impl.EntityManagerWrapper.createQuery(EntityManagerWrapper.java:455)
    at eu.comcom.kweportal.dao.ShipmentDao.getActiveOldShipments(ShipmentDao.java:196)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.glassfish.ejb.security.application.EJBSecurityManager.runMethod(EJBSecurityManager.java:1081)
    at org.glassfish.ejb.security.application.EJBSecurityManager.invoke(EJBSecurityManager.java:1153)
    at com.sun.ejb.containers.BaseContainer.invokeBeanMethod(BaseContainer.java:4695)
    at com.sun.ejb.EjbInvocation.invokeBeanMethod(EjbInvocation.java:630)
    at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:822)
    at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:582)
    at org.jboss.weld.ejb.AbstractEJBRequestScopeActivationInterceptor.aroundInvoke(Abstrac tEJBRequestScopeActivationInterceptor.java:46)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:883)
    at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:822)
    at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:582)
    at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.doCall(SystemInterceptorProxy.java:163)
    at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.aroundInvoke(SystemInterceptorProxy.java:140)
    at sun.reflect.GeneratedMethodAccessor77.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:883)
    at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:822)
    at com.sun.ejb.containers.interceptors.InterceptorManager.intercept(InterceptorManager.java:369)
    at com.sun.ejb.containers.BaseContainer.__intercept(BaseContainer.java:4667)
    at com.sun.ejb.containers.BaseContainer.intercept(BaseContainer.java:4655)
    at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:212)
    at com.sun.ejb.containers.EJBLocalObjectInvocationHandlerDelegate.invoke(EJBLoca    lObjectInvocationHandlerDelegate.java:88)
    at com.sun.proxy.$Proxy542.getActiveOldShipments(Unknown Source)
    at eu.comcom.kweportal.dao.__EJB31_Generated__ShipmentDao__Intf____Bean__.getActiveOldShipments(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.jboss.weld.util.reflection.Reflections.invokeAndUnwrap(Reflections.java:396)
    at org.jboss.weld.bean.proxy.EnterpriseBeanProxyMethodHandler.invoke(EnterpriseBeanProxyMethodHandler.java:108)
    at org.jboss.weld.bean.proxy.EnterpriseTargetBeanInstance.invoke(EnterpriseTargetBeanInstance.java:56)
    at org.jboss.weld.bean.proxy.InjectionPointPropagatingEnterpriseTargetBeanInstance.invoke(InjectionPointPropagatingEnterpriseTargetBeanInstance.java:63)
    at org.jboss.weld.bean.proxy.ProxyMethodHandler.invoke(ProxyMethodHandler.java:101)
    at eu.comcom.kweportal.dao.ShipmentDao$Proxy$_$$_Weld$EnterpriseProxy$.getActiveOldShipments(Unknown Source)
    at eu.comcom.kweportal.schedule.ActualTimeScheduler.updatePastMilestonesTimes(ActualTimeScheduler.java:41)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.glassfish.ejb.security.application.EJBSecurityManager.runMethod(EJBSecurityManager.java:1081)
    at org.glassfish.ejb.security.application.EJBSecurityManager.invoke(EJBSecurityManager.java:1153)
    at com.sun.ejb.containers.BaseContainer.invokeBeanMethod(BaseContainer.java:4695)
    at com.sun.ejb.EjbInvocation.invokeBeanMethod(EjbInvocation.java:630)
    at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:822)
    at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:582)
    at org.jboss.weld.ejb.AbstractEJBRequestScopeActivationInterceptor.aroundInvoke (AbstractEJBRequestScopeActivationInterceptor.java:55)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:883)
    at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:822)
    at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:582)
    at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.doCall(SystemInterceptorProxy.java:163)
    at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.aroundTimeout(SystemInterceptorProxy.java:145)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:883)
    at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:822)
    at com.sun.ejb.containers.interceptors.InterceptorManager.intercept(InterceptorManager.java:369)
    at com.sun.ejb.containers.BaseContainer.__intercept(BaseContainer.java:4667)
    at com.sun.ejb.containers.BaseContainer.intercept(BaseContainer.java:4655)
    at com.sun.ejb.containers.BaseContainer.callEJBTimeout(BaseContainer.java:3993)
    at com.sun.ejb.containers.EJBTimerService.deliverTimeout(EJBTimerService.java:1199)
    at com.sun.ejb.containers.EJBTimerService.access$000(EJBTimerService.java:89)
    at com.sun.ejb.containers.EJBTimerService$TaskExpiredWork.run(EJBTimerService.java:1919)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask.run(FutureTask.java:262)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:744)

和persistence.xml: 
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" 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_2_0.xsd">
  <persistence-unit name="pu_name" transaction-type="JTA">
      <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
      <jta-data-source>jdbc/kweportal</jta-data-source>
      <exclude-unlisted-classes>false</exclude-unlisted-classes>
      <properties>
          <property name="hibernate.ejb.cfgfile" value="hibernate.cfg.xml"/>
      </properties>
  </persistence-unit>
</persistence>

有什么想法可能是错的吗？

最佳答案

我自己想通了。

persistence.xml 必须如下所示:

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" xmlns="http://xmlns.jcp.org/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_2_1.xsd">
  <persistence-unit name="pu_name" transaction-type="JTA">
      <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
      <jta-data-source>jdbc/kweportal</jta-data-source>
      <exclude-unlisted-classes>false</exclude-unlisted-classes>
      <properties>
          <property name="hibernate.ejb.cfgfile" value="hibernate.cfg.xml"/>
          <property name="hibernate.transaction.jta.platform"       value="org.hibernate.service.jta.platform.internal.SunOneJtaPlatform" />
      </properties>
</persistence-unit>
</persistence>

关于hibernate - EntityManager.createQuery() 抛出 NullPointerException，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/24557929/

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