java.lang.IllegalStateException：无法为unitName CarLocPU

Question

我使用NetBeans 8.1，Glassfish 4.1和Apache Derby（包含在GlassFish中）开始使用Java EE。

为此，我打电话来存储和存储具有其属性的汽车数据。

但是这个简单的外观总是返回＆＃34; java.lang.IllegalStateException＆＃34;而我在班级文件中看不到任何错误。

这是一个非常简单的model.car实体，带有基本的getter和setter：

@Entity
@Table(name = "car")
public class Car implements java.io.Serializable {
    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE)
    private Integer id;
    private String brand;
    private String model;
    private String year;
    private String energy;
    private String hp;
    private String tp;
    private byte[] picture;

这是＆＃34; Facade＆＃34;该实体在Apache Derby中存储数据：

@Stateless
public class CarFacade extends AbstractFacade<Car> {

    @PersistenceContext(unitName = "CarLocPU")
    private EntityManager em;

    @Override
    protected EntityManager getEntityManager() {
        return em;
    }

    public CarFacade() {
        super(Car.class);
    }

}

我在调试以下异常时遇到很多麻烦，因为它是非常简单的短代码，一切都应该可以正常工作。而且，StackTrace并没有像Java SE那样显示断点。

以下是StackTrace异常：

Caused by: java.lang.IllegalStateException: Unable to retrieve EntityManagerFactory for unitName CarLocPU
    at com.sun.enterprise.container.common.impl.EntityManagerWrapper.init(EntityManagerWrapper.java:138)
    at com.sun.enterprise.container.common.impl.EntityManagerWrapper.doTxRequiredCheck(EntityManagerWrapper.java:158)
    at com.sun.enterprise.container.common.impl.EntityManagerWrapper.doTransactionScopedTxCheck(EntityManagerWrapper.java:151)
    at com.sun.enterprise.container.common.impl.EntityManagerWrapper.persist(EntityManagerWrapper.java:281)
    at facade.AbstractFacade.create(AbstractFacade.java:26)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    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:4786)
    at com.sun.ejb.EjbInvocation.invokeBeanMethod(EjbInvocation.java:656)
    at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:822)
    at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:608)
    at org.jboss.weld.ejb.AbstractEJBRequestScopeActivationInterceptor.aroundInvoke(AbstractEJBRequestScopeActivationInterceptor.java:64)
    at org.jboss.weld.ejb.SessionBeanInterceptor.aroundInvoke(SessionBeanInterceptor.java:52)
    at sun.reflect.GeneratedMethodAccessor965.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    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:608)
    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.GeneratedMethodAccessor994.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    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:4758)
    at com.sun.ejb.containers.BaseContainer.intercept(BaseContainer.java:4746)
    at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:212)
    ... 53 more

提前感谢您的帮助。

编辑：

这是项目的结构。

这是persistence.xml内容，应用程序名为＆＃34; CarLoc＆＃34;。

<?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://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
  <persistence-unit name="CarLocPU" transaction-type="JTA">
    <jta-data-source>java:app/jdbc/CarLoc</jta-data-source>
    <exclude-unlisted-classes>false</exclude-unlisted-classes>
    <properties/>
  </persistence-unit>
</persistence>

Answer 1

如果在EJB容器之外使用JPA，则需要在persistence.xml中声明JPA <provider>。

默认情况下，Glassfish使用EclipseLink作为JPA提供程序。假设您不想更改此设置，则需要更改persistence.xml以将EclipseLink声明为JPA提供程序：

<persistence xmlns="http://java.sun.com/xml/ns/persistence" version="1.0">
    <persistence-unit name="CarLocPU" transaction-type="JTA">
        <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
        <exclude-unlisted-classes>false</exclude-unlisted-classes>
        <properties>
            <property name="eclipselink.target-database" value="Derby"/>
            <!-- JDBC connection properties -->
            <property name="eclipselink.jdbc.driver" value="org.apache.derby.jdbc.ClientDriver"/>
            <property name="eclipselink.jdbc.url" value="jdbc:derby://localhost:1527/myDBName;create=true;"/>
            <property name="eclipselink.jdbc.user" value="APP"/>
            <property name="eclipselink.jdbc.password" value="APP"/>
        </properties>
    </persistence-unit>
</persistence>

来源：
Oracle Docs - Chapter 7 Using the Java Persistence API