无法使用 @PersistenceContext 注入 EntityManager [将持久性单元注入 CDI 托管 bean 时出错。]答案

【问题标题】：Cant inject EntityManager with @PersistenceContext [Error injecting persistence unit into CDI managed bean.]无法使用 @PersistenceContext 注入 EntityManager [将持久性单元注入 CDI 托管 bean 时出错。]
【发布时间】：2018-07-07 07:13:48
【问题描述】：

我有我想将 EntityManager 注入到的 Dao 对象：

    @Transactional
    public class ConfigEntryDao implements IDao<ConfigEntryEntity> {

        //THIS IS WHAT I WANT TO DO!
        @PersistenceContext(unitName = XChangeUtil.JPA.JPA_PU_NAME)
        private EntityManager entityManager;
        //ONLY THIS ONE WORKS!
        //private EntityManagerFactory emf = Persistence.createEntityManagerFactory(XChangeUtil.JPA.JPA_PU_NAME);
        //private EntityManager entityManager = emf.createEntityManager();
        //....Other methods bellow

如果我在没有注入的情况下使用带有实体管理器工厂的注释掉版本，我可以让我的代码工作，一切正常，一旦我使用 @Persistence 上下文，我得到异常：

14:18:15,854 ERROR [org.jboss.msc.service.fail] (MSC service thread 1-5) MSC000001: Failed to start service jboss.deployment.unit."xChange-1.0-SNAPSHOT.war".WeldStartService: org.jboss.msc.service.StartException in service jboss.deployment.unit."xChange-1.0-SNAPSHOT.war".WeldStartService: Failed to start service
    at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1978)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalArgumentException: WFLYWELD0037: Error injecting persistence unit into CDI managed bean. Can't find a persistence unit named 'eclipselinkPu' in deployment xChange-1.0-SNAPSHOT.war for injection point private javax.persistence.EntityManager com.bisciak.xchange.dao.ConfigEntryDao.entityManager
    at org.jboss.as.weld.services.bootstrap.WeldJpaInjectionServices.getScopedPUName(WeldJpaInjectionServices.java:114)
    at org.jboss.as.weld.services.bootstrap.WeldJpaInjectionServices.registerPersistenceContextInjectionPoint(WeldJpaInjectionServices.java:77)
    at org.jboss.weld.injection.ResourceInjectionFactory$PersistenceContextResourceInjectionProcessor.getResourceReferenceFactory(ResourceInjectionFactory.java:350)
    at org.jboss.weld.injection.ResourceInjectionFactory$PersistenceContextResourceInjectionProcessor.getResourceReferenceFactory(ResourceInjectionFactory.java:338)
    at org.jboss.weld.injection.ResourceInjectionFactory$ResourceInjectionProcessor.createFieldResourceInjection(ResourceInjectionFactory.java:216)
    at org.jboss.weld.injection.ResourceInjectionFactory$ResourceInjectionProcessor.createResourceInjections(ResourceInjectionFactory.java:188)
    at org.jboss.weld.injection.ResourceInjectionFactory.discoverType(ResourceInjectionFactory.java:448)
    at org.jboss.weld.injection.ResourceInjectionFactory.getResourceInjections(ResourceInjectionFactory.java:96)
    at org.jboss.weld.injection.producer.ResourceInjector.<init>(ResourceInjector.java:59)
    at org.jboss.weld.injection.producer.ResourceInjector.of(ResourceInjector.java:49)
    at org.jboss.weld.injection.producer.BeanInjectionTarget.<init>(BeanInjectionTarget.java:63)
    at org.jboss.weld.injection.producer.BeanInjectionTarget.createDefault(BeanInjectionTarget.java:47)
    at org.jboss.weld.manager.InjectionTargetFactoryImpl.chooseInjectionTarget(InjectionTargetFactoryImpl.java:113)
    at org.jboss.weld.manager.InjectionTargetFactoryImpl.createInjectionTarget(InjectionTargetFactoryImpl.java:86)
    at org.jboss.weld.bean.ManagedBean.<init>(ManagedBean.java:100)
    at org.jboss.weld.bean.ManagedBean.of(ManagedBean.java:80)
    at org.jboss.weld.bootstrap.AbstractBeanDeployer.createManagedBean(AbstractBeanDeployer.java:261)
    at org.jboss.weld.bootstrap.BeanDeployer.createClassBean(BeanDeployer.java:226)
    at org.jboss.weld.bootstrap.ConcurrentBeanDeployer$2.doWork(ConcurrentBeanDeployer.java:74)
    at org.jboss.weld.bootstrap.ConcurrentBeanDeployer$2.doWork(ConcurrentBeanDeployer.java:71)
    at org.jboss.weld.executor.IterativeWorkerTaskFactory$1.call(IterativeWorkerTaskFactory.java:62)
    at org.jboss.weld.executor.IterativeWorkerTaskFactory$1.call(IterativeWorkerTaskFactory.java:55)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
    at org.jboss.threads.JBossThread.run(JBossThread.java:320)

14:18:15,858 ERROR [org.jboss.as.controller.management-operation] (management-handler-thread - 3) WFLYCTL0013: Operation ("deploy") failed - address: ([("deployment" => "xChange-1.0-SNAPSHOT")]) - failure description: {"WFLYCTL0080: Failed services" => {"jboss.deployment.unit.\"xChange-1.0-SNAPSHOT.war\".WeldStartService" => "Failed to start service
    Caused by: java.lang.IllegalArgumentException: WFLYWELD0037: Error injecting persistence unit into CDI managed bean. Can't find a persistence unit named 'eclipselinkPu' in deployment xChange-1.0-SNAPSHOT.war for injection point private javax.persistence.EntityManager com.bisciak.xchange.dao.ConfigEntryDao.entityManager"}}
14:18:15,858 ERROR [org.jboss.as.server] (management-handler-thread - 3) WFLYSRV0021: Deploy of deployment "xChange-1.0-SNAPSHOT.war" was rolled back with the following failure message: 
{"WFLYCTL0080: Failed services" => {"jboss.deployment.unit.\"xChange-1.0-SNAPSHOT.war\".WeldStartService" => "Failed to start service
    Caused by: java.lang.IllegalArgumentException: WFLYWELD0037: Error injecting persistence unit into CDI managed bean. Can't find a persistence unit named 'eclipselinkPu' in deployment xChange-1.0-SNAPSHOT.war for injection point private javax.persistence.EntityManager com.bisciak.xchange.dao.ConfigEntryDao.entityManager"}}
14:18:15,862 INFO  [org.jboss.as.connector.deployers.jdbc] (MSC service thread 1-2) WFLYJCA0019: Stopped Driver service with driver-name = xChange-1.0-SNAPSHOT.war_org.apache.derby.jdbc.AutoloadedDriver_10_12
14:18:15,862 INFO  [org.jboss.as.connector.deployers.jdbc] (MSC service thread 1-4) WFLYJCA0019: Stopped Driver service with driver-name = xChange-1.0-SNAPSHOT.war_com.mysql.cj.jdbc.Driver_6_0
14:18:15,982 INFO  [org.jboss.as.server.deployment] (MSC service thread 1-2) WFLYSRV0028: Stopped deployment xChange-1.0-SNAPSHOT (runtime-name: xChange-1.0-SNAPSHOT.war) in 122ms
[2018-01-28 02:18:16,041] Artifact xChange:war exploded: Error during artifact deployment. See server log for details.
[2018-01-28 02:18:16,041] Artifact xChange:war exploded: java.lang.Exception: {"WFLYCTL0080: Failed services" => {"jboss.deployment.unit.\"xChange-1.0-SNAPSHOT.war\".WeldStartService" => "Failed to start service
    Caused by: java.lang.IllegalArgumentException: WFLYWELD0037: Error injecting persistence unit into CDI managed bean. Can't find a persistence unit named 'eclipselinkPu' in deployment xChange-1.0-SNAPSHOT.war for injection point private javax.persistence.EntityManager com.bisciak.xchange.dao.ConfigEntryDao.entityManager"}}

有趣的是 - 如果我从我的项目中删除 beans.xml，我可以使用 @PersistenceContext 注释并成功部署，那么我遇到了 问题CDI。我的 beans.xml 在 bean discovery all 旁边没有任何内容：

<?xml version="1.0" encoding="UTF-8"?>
<beans
    xmlns="http://xmlns.jcp.org/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee 
                      http://xmlns.jcp.org/xml/ns/javaee/beans_1_1.xsd"
    bean-discovery-mode="all">
</beans>

我的项目结构+persistence.xml：

这是我的ConfigEntryDao的用法：

    public class ConfigurationService {

    @Inject
    private ConfigEntryDao configEntryDao;

    private List<ConfigEntryEntity> configEntries;



    @PostConstruct
    public void initialize() {
        System.out.println("DBG Constructed");
        configEntryDao.insert(new ConfigEntryEntity(ConfigNamespace.xchange_test, "Hello"));
        configEntryDao.insert(new ConfigEntryEntity(ConfigNamespace.xchange_test_subtest, "World"));
        configEntries = configEntryDao.getAll();
    }

    public void tryTestValue() {
        System.out.println("Hello");
        System.out.println("Testing data from config db table Size: "+configEntries.size()+" Values:"+ configEntries.toString());
    }

}

我从 REST 端点测试该方法，因为我太酷了，无法使用 UI：

@Path("/test")
public class TestResource {

    @Inject
    private ConfigurationService configurationService;

    @GET
    @Path("/dbtest")
    public Response testDb() {
        System.out.println("DBG Invocation of dbtest");
        configurationService.tryTestValue();
        return Response.status(Response.Status.OK).build();
    }

}

所以问题是：有人知道我为什么不能通过 PersistenceContext 注入实体管理器吗？

注意：我使用的是最新的稳定版 Wildfly

【问题讨论】：

您确定您使用的是正确的 unitName 吗？应该是The name of the persistence unit as defined in the persistence.xml file.
@asm0dey 100% 相同...
您有一个 JTA 持久性单元但未定义 JDBC 数据源。我假设您的持久性单元没有创建。你检查过日志吗？
@Simon Martinelli 在我指定 jta 数据源时没有改变任何东西，我添加它只是为了测试，没有任何改变，仍然是同样的错误。
您说您使用的是 EclipseLink 但 Wildfly 包含 Hibernate

标签： java mysql jpa eclipselink wildfly

【解决方案1】：

您的ConfigEntryDao 应该由容器管理，以便让容器注入EntityManager。例如，通过使用 @Stateless 对其进行注释，使其成为无状态会话 bean (SLSB)。

另请参阅here，了解如何为 EntityManager 创建生产者。

【讨论】：