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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);
 
  }
 
  }