mysql - 使用 Hibernate Persistence Provider 和 MySQL DB 在 Apache TomEE 中部署 EJB

Question

我在配置基于 EJB 3.0 技术的项目时遇到问题。作为服务器容器，我使用 Apache TomEE v.7.0(内置 OpenEJB 模块)、MySQL 数据库和休眠作为持久性提供程序。

下面是我的配置文件:

tomee.xml

<?xml version="1.0" encoding="UTF-8"?>
<tomee>
<Resource id="lrsDataSource" type="javax.sql.DataSource">
    JdbcDriver com.mysql.jdbc.Driver
    JdbcUrl jdbc:mysql://localhost:3306/lbrentalservice
    UserName root
    Password 123456
    JtaManaged true
</Resource>
</tomee>

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="lrs-unit" transaction-type="JTA">
    <provider>org.hibernate.ejb.HibernatePersistence</provider>
    <jta-data-source>lrsDataSource</jta-data-source>
    <non-jta-data-source>lrsDataSourceUnmanaged</non-jta-data-source>
    <class>edu.drg.entity.Book</class>
    <class>edu.drg.entity.Category</class>
    <class>edu.drg.entity.Person</class>
    <class>edu.drg.entity.RentActivity</class>
    <properties>
      <property name="hibernate.hbm2ddl.auto" value="create"/>
      <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
      <property name="hibernate.query.factory_class"
                value="org.hibernate.hql.internal.classic.ClassicQueryTranslatorFactory" />
      <property name="hibernate.transaction.manager_lookup_class"
                value="org.apache.openejb.hibernate.TransactionManagerLookup"/>
    </properties>
  </persistence-unit>
</persistence>

人实体(其他实体类似)

@Entity
@Table (name="person", uniqueConstraints = { @UniqueConstraint(columnNames = "prs_id")})
@NamedQueries({
    @NamedQuery(name="findAllPersons", query = "SELECT p FROM Person p")
})
public class Person implements IPerson, Serializable{
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    private Long personId;
    private String personName;
    private String personSurname;

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    @Column(name="prs_id")
    public Long getPersonId() {
        return personId;
    }
    public void setPersonId(Long personId) {
        this.personId = personId;
    }
    @Column(name="name")
    public String getPersonName() {
        return personName;
    }
    public void setPersonName(String personName) {
        this.personName = personName;
    }
    @Column(name="surname")
    public String getPersonSurname() {
        return personSurname;
    }
    public void setPersonSurname(String personSurname) {
        this.personSurname = personSurname;
    }
    @Override
    public String toString() {
        return "Person [personId=" + personId + ", personName=" + personName
                + ", personSurname=" + personSurname + "]";
    }



}

管理器Bean

@Stateless(name="LRSManager")
public class LRSManagerBean implements LRSManager{
    @Resource(name="lrsDataSource")
    DataSource ds;

    @PersistenceContext(unitName="lrs-unit")
    private EntityManager entityManager;

    @Resource
    private SessionContext sessionContext;

    private static final Log logger = LogFactory.getLog(LRSManagerBean.class);
    @Override
    public void addBook (IBook book) {
        entityManager.persist(book);
    }
    @Override
    public List<IPerson> getAllPersons() {
        System.out.println("Is entityManager not null: "+entityManager!=null);
        List<IPerson> allPersons = null;
        try {
            final Query query = entityManager.createNamedQuery("findAllPersons");
            allPersons = query.getResultList();
        } catch (PersistenceException e) {
            e.printStackTrace();
        }

        return allPersons;
    }

本地接口(interface):

import javax.ejb.Local;
import edu.drg.interfaces.ILRSManager;

@Local
public interface LRSManager extends ILRSManager {

}

我正在尝试通过 servlet 中的接口(interface)管理器访问 getAllPersons() 方法，如下所示:

@WebServlet("/RetrieveAllPersons")
public class RetrieveAllPersons extends HttpServlet {
    private static final long serialVersionUID = 1L;
    //private ILRSManager manager = LRSManagerFactory.getInstance().getLRSManager();
    @EJB
    private LRSManager manager;
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        Log logger = LogFactory.getLog(this.getClass());
        logger.debug("Entering servlet");
        List<IPerson> allPersons = manager.getAllPersons();
        request.setAttribute("allPersons", allPersons);
        logger.debug("Retrieved from persons: "+allPersons);
        RequestDispatcher rd = request.getRequestDispatcher("persons.jsp");
        rd.forward(request, response);
    }

}

但是，我不知道为什么会出现以下异常:

lug 07, 2015 2:12:40 PM org.apache.openejb.core.transaction.EjbTransactionUtil handleSystemException
SEVERE: EjbTransactionUtil.handleSystemException: null
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:332)
    at org.apache.openejb.assembler.classic.ReloadableEntityManagerFactory.createEntityManager(ReloadableEntityManagerFactory.java:160)
    at org.apache.openejb.persistence.JtaEntityManagerRegistry.getEntityManager(JtaEntityManagerRegistry.java:119)
    at org.apache.openejb.persistence.JtaEntityManager.getEntityManager(JtaEntityManager.java:96)
    at org.apache.openejb.persistence.JtaEntityManager.proxyIfNoTx(JtaEntityManager.java:326)
    at org.apache.openejb.persistence.JtaEntityManager.createNamedQuery(JtaEntityManager.java:289)
    at edu.drg.ejb.LRSManagerBean.getAllPersons(LRSManagerBean.java:44)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.apache.openejb.core.interceptor.ReflectionInvocationContext$Invocation.invoke(ReflectionInvocationContext.java:192)
    at org.apache.openejb.core.interceptor.ReflectionInvocationContext.proceed(ReflectionInvocationContext.java:173)
    at org.apache.openejb.monitoring.StatsInterceptor.record(StatsInterceptor.java:181)
    at org.apache.openejb.monitoring.StatsInterceptor.invoke(StatsInterceptor.java:100)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.apache.openejb.core.interceptor.ReflectionInvocationContext$Invocation.invoke(ReflectionInvocationContext.java:192)
    at org.apache.openejb.core.interceptor.ReflectionInvocationContext.proceed(ReflectionInvocationContext.java:173)
    at org.apache.openejb.core.interceptor.InterceptorStack.invoke(InterceptorStack.java:85)
    at org.apache.openejb.core.stateless.StatelessContainer._invoke(StatelessContainer.java:227)
    at org.apache.openejb.core.stateless.StatelessContainer.invoke(StatelessContainer.java:194)
    at org.apache.openejb.core.ivm.EjbObjectProxyHandler.synchronizedBusinessMethod(EjbObjectProxyHandler.java:308)
    at org.apache.openejb.core.ivm.EjbObjectProxyHandler.businessMethod(EjbObjectProxyHandler.java:303)
    at org.apache.openejb.core.ivm.EjbObjectProxyHandler._invoke(EjbObjectProxyHandler.java:92)
    at org.apache.openejb.core.ivm.BaseEjbProxyHandler.invoke(BaseEjbProxyHandler.java:308)
    at com.sun.proxy.$Proxy76.getAllPersons(Unknown Source)
    at edu.drg.servlet.RetrieveAllPersons.doPost(RetrieveAllPersons.java:36)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
    at org.apache.tomee.catalina.OpenEJBValve.invoke(OpenEJBValve.java:44)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Unknown Source)

lug 07, 2015 2:12:40 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [edu.drg.servlet.RetrieveAllPersons] in context with path [/TestingEJB] threw exception
javax.ejb.EJBException: The bean encountered a non-application exception; nested exception is: 
    java.lang.NullPointerException
    at org.apache.openejb.core.ivm.BaseEjbProxyHandler.convertException(BaseEjbProxyHandler.java:408)
    at org.apache.openejb.core.ivm.BaseEjbProxyHandler.invoke(BaseEjbProxyHandler.java:312)
    at com.sun.proxy.$Proxy76.getAllPersons(Unknown Source)
    at edu.drg.servlet.RetrieveAllPersons.doPost(RetrieveAllPersons.java:36)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
    at org.apache.tomee.catalina.OpenEJBValve.invoke(OpenEJBValve.java:44)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException
    at org.hibernate.engine.transaction.internal.jta.JtaStatusHelper.getStatus(JtaStatusHelper.java:76)
    at org.hibernate.engine.transaction.internal.jta.JtaStatusHelper.isActive(JtaStatusHelper.java:118)
    at org.hibernate.engine.transaction.internal.jta.CMTTransaction.join(CMTTransaction.java:149)
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.joinTransaction(AbstractEntityManagerImpl.java:1602)
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.postInit(AbstractEntityManagerImpl.java:210)
    at org.hibernate.jpa.internal.EntityManagerImpl.<init>(EntityManagerImpl.java:91)
    at org.hibernate.jpa.internal.EntityManagerFactoryImpl.internalCreateEntityManager(EntityManagerFactoryImpl.java:345)
    at org.hibernate.jpa.internal.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:332)
    at org.apache.openejb.assembler.classic.ReloadableEntityManagerFactory.createEntityManager(ReloadableEntityManagerFactory.java:160)
    at org.apache.openejb.persistence.JtaEntityManagerRegistry.getEntityManager(JtaEntityManagerRegistry.java:119)
    at org.apache.openejb.persistence.JtaEntityManager.getEntityManager(JtaEntityManager.java:96)
    at org.apache.openejb.persistence.JtaEntityManager.proxyIfNoTx(JtaEntityManager.java:326)
    at org.apache.openejb.persistence.JtaEntityManager.createNamedQuery(JtaEntityManager.java:289)
    at edu.drg.ejb.LRSManagerBean.getAllPersons(LRSManagerBean.java:44)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.apache.openejb.core.interceptor.ReflectionInvocationContext$Invocation.invoke(ReflectionInvocationContext.java:192)
    at org.apache.openejb.core.interceptor.ReflectionInvocationContext.proceed(ReflectionInvocationContext.java:173)
    at org.apache.openejb.monitoring.StatsInterceptor.record(StatsInterceptor.java:181)
    at org.apache.openejb.monitoring.StatsInterceptor.invoke(StatsInterceptor.java:100)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.apache.openejb.core.interceptor.ReflectionInvocationContext$Invocation.invoke(ReflectionInvocationContext.java:192)
    at org.apache.openejb.core.interceptor.ReflectionInvocationContext.proceed(ReflectionInvocationContext.java:173)
    at org.apache.openejb.core.interceptor.InterceptorStack.invoke(InterceptorStack.java:85)
    at org.apache.openejb.core.stateless.StatelessContainer._invoke(StatelessContainer.java:227)
    at org.apache.openejb.core.stateless.StatelessContainer.invoke(StatelessContainer.java:194)
    at org.apache.openejb.core.ivm.EjbObjectProxyHandler.synchronizedBusinessMethod(EjbObjectProxyHandler.java:308)
    at org.apache.openejb.core.ivm.EjbObjectProxyHandler.businessMethod(EjbObjectProxyHandler.java:303)
    at org.apache.openejb.core.ivm.EjbObjectProxyHandler._invoke(EjbObjectProxyHandler.java:92)
    at org.apache.openejb.core.ivm.BaseEjbProxyHandler.invoke(BaseEjbProxyHandler.java:308)
    ... 25 more

TransactionManager 似乎有问题，我想知道我是否仍然需要通过 hibernate.cfg.xml 映射我的实体并将此映射添加为对 persistence.xml 的引用。我还注意到，当我尝试访问我的方法时，entitymanager 从表中删除了我的所有记录。我仍然没有找到任何可以帮助我处理 tomee 文档的东西。有什么想法吗？

Answer 1

找到了解决方案，可能对某人有用。

由于我们要使用 Hibernate Persistence Provider 和 JTA，因此事务管理器也应该是相应的，直到现在我一直在尝试使用隐式的开放式 ejb 事务管理器。

要解决这个问题，我们应该在persistence.xml中使用，而不是

<property name="hibernate.transaction.manager_lookup_class"
                value="org.apache.openejb.hibernate.TransactionManagerLookup"/>

这个:

<property
    name="transaction.factory_class" value="org.hibernate.transaction.JTATransactionFactory"/>

还要注意您使用的休眠版本，我使用的是 4.x，提供者

<provider>org.hibernate.ejb.HibernatePersistence</provider>

已弃用，请改用它:

<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>