简单的Hibernate应用程序不工作：PropertyAccessException：无法通过反射getter获取字段值

2022-08-05 00:00:00 mysql java Hibernate ejb jta

我正在努力使用一个简单的Hibernate应用程序。(JBoss AS 7.1.1，Hibernate 4.1)

我的实体Bean：

@Entity
public class User implements Serializable {

    @Id
    private Long userId;

    public Long getUserId() {
    return userId;
    }

    public void setUserId(Long userId) {
        this.userId = userId;
    }
}

My Persistence.xml：

<persistence 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"
version="2.0">
<persistence-unit name="users" transaction-type="JTA">
    <provider>org.hibernate.ejb.HibernatePersistence</provider>
    <jta-data-source>java:jboss/datasources/myDS</jta-data-source>
    <jar-file>users.jar</jar-file>
    <class>de.test.users.entities.User</class>
    <properties>
        <property name="hibernate.hbm2ddl.auto" value="update" />
        <property name="hibernate.archive.autodetection" value="class" />
        <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
        <property name="hibernate.show_sql" value="true" />
    </properties>
</persistence-unit>

我的简单DAO Bean：

@Stateless
public class UserManagerBean implements UserManager {

    @PersistenceContext(name = "users")
    private EntityManager em;

    public UserManagerBean() {
        // TODO Auto-generated constructor stub
    }

    @Override
    public void createUser() {
        User user = new User();
            user.setUserId(42L);
    em.persist(user);
    em.flush();
    }
}

我通过在JSF支持的Bean中注入UserManagerBean来调用createUser方法。当调用Persistent方法时，我得到以下内容：

javax.faces.el.EvaluationException: javax.ejb.EJBException: javax.persistence.PersistenceException: org.hibernate.PropertyAccessException: could not get a field value by reflection getter of de.test.users.entities.User.userId
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:102)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
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.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:329)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248)
at org.jboss.weld.servlet.ConversationPropagationFilter.doFilter(ConversationPropagationFilter.java:62)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:280)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:275)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161)
at org.jboss.as.jpa.interceptor.WebNonTxEmCloserValve.invoke(WebNonTxEmCloserValve.java:50)
at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:153)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:155)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:368)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:877)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:671)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:930)
at java.lang.Thread.run(Thread.java:722)
Caused by: javax.ejb.EJBException: javax.persistence.PersistenceException: org.hibernate.PropertyAccessException: could not get a field value by reflection getter of de.test.users.entities.User.userId
at org.jboss.as.ejb3.tx.CMTTxInterceptor.handleExceptionInOurTx(CMTTxInterceptor.java:166)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInOurTx(CMTTxInterceptor.java:230)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.required(CMTTxInterceptor.java:304)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.processInvocation(CMTTxInterceptor.java:190)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.as.ejb3.component.interceptors.CurrentInvocationContextInterceptor.processInvocation(CurrentInvocationContextInterceptor.java:41)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.as.ejb3.component.interceptors.LoggingInterceptor.processInvocation(LoggingInterceptor.java:59)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.as.ee.component.NamespaceContextInterceptor.processInvocation(NamespaceContextInterceptor.java:50)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.as.ejb3.component.interceptors.AdditionalSetupInterceptor.processInvocation(AdditionalSetupInterceptor.java:32)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.as.ee.component.TCCLInterceptor.processInvocation(TCCLInterceptor.java:45)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61)
at org.jboss.as.ee.component.ViewService$View.invoke(ViewService.java:165)
at org.jboss.as.ee.component.ViewDescription$1.processInvocation(ViewDescription.java:173)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61)
at org.jboss.as.ee.component.ProxyInvocationHandler.invoke(ProxyInvocationHandler.java:72)
at de.test.users.service.UserManager$$$view1.createUser(Unknown Source)
at de.test.users.User.createUser(User.java:17)
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:601)
at org.apache.el.parser.AstValue.invoke(AstValue.java:262)
at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:278)
at org.jboss.weld.util.el.ForwardingMethodExpression.invoke(ForwardingMethodExpression.java:39)
at org.jboss.weld.el.WeldMethodExpression.invoke(WeldMethodExpression.java:50)
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:88)
... 25 more
Caused by: javax.persistence.PersistenceException: org.hibernate.PropertyAccessException: could not get a field value by reflection getter of de.test.users.entities.User.userId
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1361)
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1289)
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1295)
at org.hibernate.ejb.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:859)
at org.jboss.as.jpa.container.AbstractEntityManager.persist(AbstractEntityManager.java:563)
at de.test.users.service.UserManagerBean.createUser(UserManagerBean.java:31)
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:601)
at org.jboss.as.ee.component.ManagedReferenceMethodInterceptorFactory$ManagedReferenceMethodInterceptor.processInvocation(ManagedReferenceMethodInterceptorFactory.java:72)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.invocation.InterceptorContext$Invocation.proceed(InterceptorContext.java:374)
at org.jboss.as.weld.ejb.Jsr299BindingsInterceptor.doMethodInterception(Jsr299BindingsInterceptor.java:127)
at org.jboss.as.weld.ejb.Jsr299BindingsInterceptor.processInvocation(Jsr299BindingsInterceptor.java:135)
at org.jboss.as.ee.component.interceptors.UserInterceptorFactory$1.processInvocation(UserInterceptorFactory.java:36)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.invocation.WeavedInterceptor.processInvocation(WeavedInterceptor.java:53)
at org.jboss.as.ee.component.interceptors.UserInterceptorFactory$1.processInvocation(UserInterceptorFactory.java:36)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.as.jpa.interceptor.SBInvocationInterceptor.processInvocation(SBInvocationInterceptor.java:47)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.as.weld.ejb.EjbRequestScopeActivationInterceptor.processInvocation(EjbRequestScopeActivationInterceptor.java:82)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.invocation.InitialInterceptor.processInvocation(InitialInterceptor.java:21)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61)
at org.jboss.as.ee.component.interceptors.ComponentDispatcherInterceptor.processInvocation(ComponentDispatcherInterceptor.java:53)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.as.ejb3.component.pool.PooledInstanceInterceptor.processInvocation(PooledInstanceInterceptor.java:51)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInOurTx(CMTTxInterceptor.java:228)
... 56 more
 Caused by: org.hibernate.PropertyAccessException: could not get a field value by reflection getter of de.test.users.entities.User.userId
at org.hibernate.property.DirectPropertyAccessor$DirectGetter.get(DirectPropertyAccessor.java:61)
at org.hibernate.tuple.entity.AbstractEntityTuplizer.getIdentifier(AbstractEntityTuplizer.java:341)
at org.hibernate.persister.entity.AbstractEntityPersister.getIdentifier(AbstractEntityPersister.java:4260)
at org.hibernate.persister.entity.AbstractEntityPersister.isTransient(AbstractEntityPersister.java:3982)
at org.hibernate.engine.internal.ForeignKeys.isTransient(ForeignKeys.java:209)
at org.hibernate.event.internal.AbstractSaveEventListener.getEntityState(AbstractSaveEventListener.java:509)
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:118)
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:78)
at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:725)
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:701)
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:705)
at org.hibernate.ejb.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:853)
... 84 more
 Caused by: java.lang.IllegalArgumentException: Can not set java.lang.Long field de.test.users.entities.User.userId to de.test.users.entities.User
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:164)
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:168)
at sun.reflect.UnsafeFieldAccessorImpl.ensureObj(UnsafeFieldAccessorImpl.java:55)
at sun.reflect.UnsafeObjectFieldAccessorImpl.get(UnsafeObjectFieldAccessorImpl.java:36)
at java.lang.reflect.Field.get(Field.java:372)
at org.hibernate.property.DirectPropertyAccessor$DirectGetter.get(DirectPropertyAccessor.java:58)
... 95 more

你知道我该怎么解决这个问题吗？顺便说一句，Hibernate似乎不能自动检测JAR文件中的类。当我从sistence.xml中删除类元素时，日志告诉我Hibernate没有为"USERS"持久化单元加载任何实体。这是否与这一例外有关？

我的项目结构多多少少是这样的：

project-ear
|-- lib
|-- META-INF
|   |
|   |-- maven
|   |-- persistence.xml
|   |-- application.xml
|
|-- users.jar
|
|-- users.war

解决方案

我能够自己解决该问题。我看到包含实体Bean的user.jar实际上被Maven复制了。它被放置在user.war的lib文件夹以及EAR包的根lib文件夹中。我将其从WAR包的lib文件夹中删除，现在一切正常，包括Hibernate的类自动检测。

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