如何使用休眠设置 UserTransaction

Question

我有一个用于管理用户信息的 mySQL 数据库，我的 mySQL 数据库使用 JTA 数据源，下面是 persistence.xml 的样子：

<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="SensorCloudPU" transaction-type="JTA">
      <jta-data-source>java:/SensorCloudPU</jta-data-source>
<!--      <non-jta-data-source>java:/SensorCloudPU</non-jta-data-source> -->
      <class>com.sensorhound.common.domain.impl.AnomalousInfo</class>
      <class>com.sensorhound.common.domain.impl.Code</class>
      <class>com.sensorhound.common.domain.impl.Device</class>
      <class>com.sensorhound.common.domain.impl.Executable</class>
      <class>com.sensorhound.common.domain.impl.Group</class>
      <class>com.sensorhound.common.domain.impl.GroupAlert</class>
      <class>com.sensorhound.common.domain.impl.GroupRule</class>
      <class>com.sensorhound.common.domain.impl.GroupRuleDefinition</class>
      <class>com.sensorhound.common.domain.impl.GroupRuleStatus</class>
      <class>com.sensorhound.common.domain.impl.Node</class>
      <class>com.sensorhound.common.domain.impl.NodeAlert</class>
      <class>com.sensorhound.common.domain.impl.NodeRule</class>
      <class>com.sensorhound.common.domain.impl.NodeRuleDefinition</class>
      <class>com.sensorhound.common.domain.impl.Organization</class>
      <class>com.sensorhound.common.domain.impl.PastGroupStatus</class>
      <class>com.sensorhound.common.domain.impl.Trace</class>
      <class>com.sensorhound.common.domain.impl.TrainingSession</class>
      <class>com.sensorhound.common.domain.impl.User</class>
      <class>com.sensorhound.common.domain.impl.Role</class>
      <exclude-unlisted-classes>true</exclude-unlisted-classes>
      <properties>
         <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
         <property name="hibernate.hbm2ddl.auto" value="update"/>
         <property name="hibernate.show_sql" value = "false" />
         <property name="hibernate.connection.autocommit" value="true" />
         <property name="hibernate.event.merge.entity_copy_observer" value="allow"/>
         <property name="transaction.factory_class" value="org.hibernate.transaction.JTATransactionFactory"/>
         <property name="jta.UserTransaction" value="java:jboss/UserTransaction"/>
      </properties>
   </persistence-unit>
</persistence>

我有一个这样的端点：

@Path("/delete")
  @POST
  @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
  @Produces(MediaType.APPLICATION_JSON)
  public Response deleteUser(@FormParam("organization_id") Integer organizationId,
      @FormParam("username") String username) throws JsonProcessingException, NotSupportedException,
      SystemException, SecurityException, IllegalStateException, RollbackException,
      HeuristicMixedException, HeuristicRollbackException, NamingException {
    Organization org = organizationDAO.getByOrganizationId(organizationId);
    userDao.deleteUserByUserNameAndOrganization(username, org);
    return Response.status(Response.Status.OK).build();
  }

DAO 是这样的：

public class userDAO {
  @PersistenceContext(unitName = "SensorCloudPU")
  protected EntityManager em;

  @Resource
  protected UserTransaction utx;

  public void deleteUserByUserNameAndOrganization(String userName, Organization org)
          throws NotSupportedException, SystemException, SecurityException, IllegalStateException,
          RollbackException, HeuristicMixedException, HeuristicRollbackException {
        Query q = this.em.createNamedQuery(User.Q_GET_BY_USERNAME_AND_ORGANIZATION);
        q.setParameter("organization", org);
        q.setParameter("user_name", userName);
        User u = this.executeQueryForSingleResult(q);
        if (u == null) {
          return;
        }
        utx.begin();
        this.em.remove(u);
        utx.commit();
      }
}

但是每次加载页面并尝试从数据库中删除时，我都会收到此错误：

注入资源查找失败：java:jboss/UserTransaction]

UserTransaction [根异常是 java.lang.IllegalStateException：WFLYEJB0137：只允许具有 bean 管理的事务划分的会话和消息驱动的 bean 访问 UserTransaction]

Answer 1

您不能在 EJB 中使用 UserTransaction，除非您添加 @TransactionManagement(BEAN)

TransactionManagement 所做的是

指定会话 bean 或消息驱动的 bean 是否具有容器管理的事务或 bean 管理的事务。如果不使用此注释，则假定该 bean 具有容器管理的事务管理。

@TransactionManagement(BEAN)
public class userDAO {

Answer 2

由于您主要关注事务管理，因此我建议您将 DAO 转换为 EJB。只需要一行：

@Stateless
public class userDAO {

    @PersistenceContext(unitName = "SensorCloudPU")
    protected EntityManager em;

    public void deleteUserByUserNameAndOrganization(String userName, Organization org) {
        Query q = this.em.createNamedQuery(User.Q_GET_BY_USERNAME_AND_ORGANIZATION);
        q.setParameter("organization", org);
        q.setParameter("user_name", userName);
        User u = this.executeQueryForSingleResult(q);
        if (u != null) {
            this.em.remove(u);
        }
    }
}

你可以看到它大大简化了事情。 EJB 免费为您提供 JTA 事务划分（如果需要还可以回滚）。

即使您正在构建仅 WAR 的部署，这也会起作用。

如果需要，您还可以将 @Stateless 添加到您的 JAX-RS 端点。至少你会得到比其他方式更多的监控。

如何使用休眠设置 UserTransaction

How to set up UserTransaction with hibernate

java

mysql

hibernate

wildfly

jta