在服务方法返回后开始的Spring声明式事务

Question

我一直在通过使用以下方式实现JavaEE Web应用程序来自学Spring™。

• Tomcat 7
• Spring 3.0，安全3.1
• JPA ：EclipseLink 2.3.1
• MySQL 5.5，Connector / J 5.1

---

我的问题是：

• 我使用Spring AOP在服务层上设置了声明式事务管理。
• （我还有一个Spring AOP日志拦截器，在同一个地方声明。）
• 创建新实体不是问题。
• 正在更新现有实体！

• 根据日志，服务方法在交易开始之前返回！

  [org.springframework.orm.jpa.JpaTransactionManager] - <Using transaction object [org.springframework.orm.jpa.JpaTransactionManager$JpaTransactionObject@335f5e3a]>
  [org.springframework.orm.jpa.JpaTransactionManager] - <Creating new transaction with name [org.snowjak.livesavegive.data.service.TagService.rename]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT>
  [org.springframework.orm.jpa.JpaTransactionManager] - <Opened new EntityManager [org.eclipse.persistence.internal.jpa.EntityManagerImpl@3a234c2f] for JPA transaction>
  [org.springframework.orm.jpa.JpaTransactionManager] - <Exposing JPA transaction as JDBC transaction [SimpleConnectionHandle: com.mysql.jdbc.JDBC4Connection@49116f61]>
  [myproject.data.service.MyEntityService] - <Beginning method: rename>
  [myproject.data.dao.MyEntityDao] - <Beginning method: get>
  [myproject.data.dao.MyEntityDao] - <After method: get>
  [myproject.data.dao.AbstractDao] - <Beginning method: update>
  [myproject.data.dao.AbstractDao] - <After method: update>
  [myproject.data.service.MyEntityService] - <After method: rename>
  [org.springframework.orm.jpa.JpaTransactionManager] - <Triggering beforeCommit synchronization>
  [org.springframework.orm.jpa.JpaTransactionManager] - <Triggering beforeCompletion synchronization>
  [org.springframework.orm.jpa.JpaTransactionManager] - <Initiating transaction commit>
  [org.springframework.orm.jpa.JpaTransactionManager] - <Committing JPA transaction on EntityManager [org.eclipse.persistence.internal.jpa.EntityManagerImpl@3a234c2f]>
  [org.springframework.orm.jpa.JpaTransactionManager] - <Triggering afterCommit synchronization>
  [org.springframework.orm.jpa.JpaTransactionManager] - <Triggering afterCompletion synchronization>
  [org.springframework.orm.jpa.JpaTransactionManager] - <Closing JPA EntityManager [org.eclipse.persistence.internal.jpa.EntityManagerImpl@3a234c2f] after transaction>
  

<击>

• 如果我的DAO是事务性的，而不是我的服务层，则无法更新无效。

• 但当局说那是坏风格。

<击>

任何人都可以提供公会的任何指针/提示/技巧/秘密吗？

<击>

编辑：

我在记录器中打开了org.springframework的DEBUG详细信息;并且从我所知道的情况来看，交易正在被正确处理 - 即在相关服务方法之前和之后开始。

我仍然有更新问题，即。我的更新没有出现在PU和DB中;现在为什么会这样？ ...

编辑：

我在进行更新尝试时也偷看了MySQL通用日志。看来，JPA根本就不是向数据库发出UPDATE！

=============================================== ===================================

实体：

• 在myproject.data.entity下。没什么特别的。通用JPA。

  @Entity
  public class MyEntity implements Serializable {
      @Id
      @GeneratedValue(strategy=GenerationType.AUTO)
      int id;
  
      @Column(nullable=false, unique=true)
      String name;
  
      ...
  }
  

---

的DAO：

myproject.data.dao下的界面。

• interface AbstractDao

  @Repository
  interface AbstractDao<T,K> extends Serializable {
      public T get(K key);
      public Collection<T> getAll();
  
      public T save(T entity);
      public T update(T entity);
  }
  

• interface MyEntityDao

  @Repository
  interface MyEntityDao extends AbstractDao<MyEntity, Integer> {
      public MyEntity get(String name);
  }
  

myproject.data.dao.jpa下的实施。

• abstract class AbstractDaoJpa

  @Repository
  abstract class AbstractDaoJpa implements AbstractDao<T,K> {
      protected EntityManager em;
      @PersistenceContext
      public void setEntityManager(EntityManager entityManager) {
          em = entityManager;
      }
  
      public T save(T entity) {
          em.persist(entity);
          return entity;
      }
  
      public T update(T entity) {
          return em.merge(entity);
      }
  }
  

• class MyEntityDaoJpa extends AbstractDaoJpa implements MyEntityDao

  @Repository
  class MyEntityDaoJpa extends AbstractDaoJpa<MyEntity,Integer> implements MyEntityDao {
      @Override
      public MyEntity get(Integer key) {
          return em.find(MyEntity.class, key);
      }
  
      @Override
      public MyEntity get(String name) {
          return em.createQuery("select E from MyEntity E where E.name = :name", MyEntity.class).setParameter("name", name).getSingleResult();
      }
  
      ...
  }
  

---

服务层：

myproject.data.service

下的界面

• interface EntityService

  @Service
  public interface EntityService<T> extends Serializable {
      public Collection<T> getAll();
  }
  

• interface MyEntityService extends EntityService

  @Service
  public interface MyEntityService extends EntityService<MyEntity> {
      public MyEntity create(String name);
      public MyEntity get(String name);
  
      public MyEntity rename(String name);
  
      ...
  }
  

myproject.data.service.impl

下的实施

• class MyEntityServiceImpl implements MyEntityService

  @Service
  public class MyEntityServiceImpl implements MyEntityService {
      private MyEntityDao dao;
  
      public MyEntityServiceImpl(MyEntityDao newDao) {
          dao = newDao;
      }
  
      @Override
      public MyEntity create(String name) {
          MyEntity e = new MyEntity();
          e.name = name;
          ...
          return dao.save(e);
      }
  
      ...
  
      @Override
      public MyEntity rename(String oldName, String newName) {
          MyEntity e = dao.get(oldName);
          e.name = newName;
          dao.update(e); // An attempt to fix by explicitly merging the modified entity.
                         // Didn't fix the problem.
          return e;
      }
  
      ...
  }
  

---

Spring配置：

...

[ Declaration of DAOs and Service beans. Appropriate DAOs are injected into Service beans. ]

...

<!-- Tomcat-managed DataSource lookup via JNDI -->
<jee:jndi-lookup id="dataSource" jndi-name="jdbc/myDS"/>

<!-- Configure the EntityManagerFactory -->
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <property name="dataSource" ref="dataSource"/>
    <property name="loadTimeWeaver">
        <bean class="org.springframework.instrument.classloading.ReflectiveLoadTimeWeaver"/>
    </property>
    <property name="jpaVendorAdapter">
        <bean class="org.springframework.orm.jpa.vendor.EclipseLinkJpaVendorAdapter"/>
    </property>
</bean>

<!-- Create the Transaction Manager -->
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactory"/>
</bean>

<!-- Configure the Transaction Manager for AOP -->
<tx:advice id="txAdvice" transaction-manager="transactionManager">
    <tx:attributes>
        <!-- Some methods are read-only. -->
        <tx:method name="get*" read-only="true" propagation="SUPPORTS"/>
        <!-- All others, use defaults. -->
        <tx:method name="*"/>
    </tx:attributes>
</tx:advice>

...

<!-- Configure Spring AOP -->
<aop:config>
    <aop:pointcut id="wholeProject" expression="within(myproject..*)"/>
    <aop:pointcut id="serviceLayerOperation" expression="execution(* myproject.data.service.*.*(..))"/>

    <!-- Configure transaction management. -->
    <aop:advisor advice-ref="txAdvice" order="1" pointcut-ref="serviceLayerOperation"/>

    <!-- Configure logging interceptor. -->
    ...
</aop:config>

Answer 1

问题来自于您直接访问实体的字段而无需通过getter / setter。

使用公共字段是一种非常糟糕的做法，因为它破坏了封装。 EclipseLink似乎需要方法，可能是因为编织包括在方法中添加字节码。通过直接访问字段，您必须绕过使EclipseLink工作的字节码添加。