[转]Hibernate 事件监听

Hibernate 事件监听

事件监听是JDK中常见的一种模式。 Hibernate中的事件监听机制可以对Session对象的动作进行监听，一旦发生了特殊的事件，Hibernate就会调用监听器类中的事件处理方法。在某些功能的设计中，既可以使用Hibernate的拦截器实现，也可以使用Hibernate的事件监听来实现。

Hibernate 定义了多个事件涵盖了持久化过程中的不同生命同期，即Session对象中的第一个方法均分别对应事件。调用某个方法时就会触发相应的事件，并被预先设置的监听器收到及处理。

Hibernate中事件监听器接口均在org.hibernate.event包中，事件与监听器接口对应关系如下：

事件类型                                 对应的监听器接口

auto-flush                                AutoFlushEventListener

merge                                     MergeEventListener

delete                                     DeleteEventListener

persist                                    PersistEventListener

dirty-check                             DirtyCheckEventListener

evict                                      EvictEventListener

flush                                      FlushEventListener

flush-entity                             FlushEntityEventListener

load                                       LoadEventListener

load-collection                         LoadCollectionEventListener

lock                                       LockEventListener

refresh                                   RefreshEventListener

replicate                                 ReplicateEventListener

save-update                            SaveUpdateEventListener

pre-load                                  PreLoadEventListener

pre-update                              PreUpdateEventListener

pre-delete                               PreDeleteEventListener

pre-insert                                PreInsertEventListener

post-load                                 PostLoadEventListener

post-update                             PostUpdateEventListener

post-delete                              PostDeleteEventListener

post-insert                              PostInsertEventListener

注意：pre和post表示事件发生之前和之后。

Hibernate 事件监听的使用方法如下：

1、用户定制事件监听器首先需要与要处理事件相对应的接口，或者继承实现这个接口的类，然后通过 Hibernate的配置（hibernate.cfg.xml）配置事件监听器对象。如：

public class LogPostLoadEventListener implements PostLoadEventListener{
  public void onPostLoad(PostLoadEvent event){
    ......
    ...
    .....
  }
}

在Hibernate的配置文件中使用<listener>标签添加事件监听器功能：

<mapping resource ="..." />
<listener type="post-load" class="com.kkoolerter.Listener.LogPostLoadEventListener" />

然而，也可以通过编程方式加载事件监听器对象：

Configuration cfg = new Configuration();
cfg.setListener("post-load",new LogPostLoadEventListener());

cfg.configure();

实现的代码如下：

public interface Auditable {

}

public class AuditLog implements Serializable {
    private Integer id;
    private String entityName;
    private String entityId;
    private Date createTime;
    private String operationType;
....

}

public class Product implements Serializable ,Auditable{
    private String id;
    private String name;
    private Double price;
    private String description;

...

}

public enum OperationType {
    LoAD,CREATE,UPDATE,DELETE

}

配置文件如下：

<hibernate-mapping>
    <class name="com.kkoolerter.hibernate.beans.AuditLog">
        <id name="id">
            <generator class="increment" />
        </id>
        <property name="entityName" />
        <property name="entityId" />
        <property name="createTime" />
        <property name="operationType" />
    </class>
</hibernate-mapping>

<hibernate-mapping>
    <class name="com.kkoolerter.hibernate.beans.Product">
        <id name="id">
            <generator class="uuid" />
        </id>
        <property name="name" />
        <property name="price" />
        <property name="description" />
    </class>
</hibernate-mapping>

<hibernate-configuration>

    <session-factory>
        <property name="dialect">
            org.hibernate.dialect.MySQLDialect
    </property>
        <property name="connection.url">
            jdbc:mysql://localhost:3306/hibernate_listener
    </property>
        <property name="connection.username">root</property>
        <property name="connection.password">123456</property>
        <property name="connection.driver_class">
            com.mysql.jdbc.Driver
    </property>
        <property name="show_sql">true</property>
        <mapping resource="com/kkoolerter/hibernate/beans/AuditLog.hbm.xml" />
        <mapping resource="com/kkoolerter/hibernate/beans/Product.hbm.xml" />
        <listener type="post-insert"
            class="com.kkoolerter.hibernate.listener.AuditLogEventListener" />
        <listener type="post-update"
            class="com.kkoolerter.hibernate.listener.AuditLogEventListener" />
        <listener type="post-delete"
            class="com.kkoolerter.hibernate.listener.AuditLogEventListener" />
    </session-factory>

</hibernate-configuration>

实现监听器的类：

public class AuditLogEventListener implements PostUpdateEventListener,
        PostInsertEventListener, PostDeleteEventListener {
    private static final long serialVersionUID = 1L;

    public void onPostUpdate(PostUpdateEvent event) {
       if(event.getEntity() instanceof Auditable){
           String entityName = event.getEntity().getClass().getName();
           AuditLog log = new AuditLog();
           log.setEntityName(entityName);
           log.setOperationType(OperationType.UPDATE.toString());
           log.setEntityId(event.getId().toString());
           log.setCreateTime(new Date());
           this.saveAuditLog(event.getSession(), log);
       }
    }

    public void onPostInsert(PostInsertEvent event) {
        if(event.getEntity() instanceof Auditable){
               String entityName = event.getEntity().getClass().getName();
               AuditLog log = new AuditLog();
               log.setEntityName(entityName);
               log.setOperationType(OperationType.CREATE.toString());
               log.setEntityId(event.getId().toString());
               log.setCreateTime(new Date());
               this.saveAuditLog(event.getSession(), log);
           }
    }

    public void onPostDelete(PostDeleteEvent event) {
        if(event.getEntity() instanceof Auditable){
               String entityName = event.getEntity().getClass().getName();
               AuditLog log = new AuditLog();
               log.setEntityName(entityName);
               log.setOperationType(OperationType.DELETE.toString());
               log.setEntityId(event.getId().toString());
               log.setCreateTime(new Date());
               this.saveAuditLog(event.getSession(), log);
           }
    }
    private void saveAuditLog(Session session,AuditLog log){
        Session logSession = session.getSessionFactory().openSession();
        Transaction tx = logSession.beginTransaction();
        try {
            tx.begin();
            logSession.save(log);
            tx.commit();
        } catch (Exception e) {
            tx.rollback();
            e.printStackTrace();
        }
    }

}

测试代码：

public class ListenerTest extends TestCase{
    public void testAdd(){
        Product p1 = new Product();
        p1.setDescription("Product 2");
        p1.setName("p2");
        p1.setPrice(3.3);
        Session session  = HibernateUtils.getCurrentSession();
        Transaction tx = session.beginTransaction();
        session.save(p1);
        tx.commit();
        HibernateUtils.closeSession(session);
    }
    public void testUpdate(){
        Session session  = HibernateUtils.getCurrentSession();
        Transaction tx = session.beginTransaction();
        Product p = (Product)session.get(Product.class,"402881ff278fefcf01278fefd0fe0001");
        //session.save(p1);
        p.setName("product 1");
        session.saveOrUpdate(p);
        tx.commit();
        HibernateUtils.closeSession(session);
    }
public void testDelete(){
        Session session  = HibernateUtils.getCurrentSession();
        Transaction tx = session.beginTransaction();
        Product p = (Product)session.get(Product.class,"402881ff278fefcf01278fefd0fe0001");
        //session.save(p1);
        //p.setName("product 1");
        session.delete(p);
        tx.commit();
        HibernateUtils.closeSession(session);
    }

}

评论

2 楼 monkmonk0 2012-02-09  

我想问下，pre和post分别在什么地方使用啊，post执行时要保存的数据是不是已经入库了

1 楼 monkmonk0 2012-02-09