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Interceptor接口提供了从会话(session)回调(callback)应用程序(application)的机制， 这种回调机制可以允许应用程序在持久化对象被保存、更新、删除或是加载之前，检查并（或）修改其 属性。一个可能的用途，就是用来跟踪审核(auditing)信息。例如：下面的这个拦截器，会在一个实现了 Auditable接口的对象被创建时自动地设置createTimestamp属性，并在实现了 Auditable接口的对象被更新时，同步更新lastUpdateTimestamp属性。
你可以直接实现Interceptor接口，也可以（最好）继承自EmptyInterceptor。
package org.hibernate.test; import java.io.Serializable; import java.util.Date; import java.util.Iterator; import org.hibernate.EmptyInterceptor; import org.hibernate.Transaction; import org.hibernate.type.Type; public class AuditInterceptor extends EmptyInterceptor { private int updates; private int creates; private int loads; public void onDelete(Object entity, Serializable id, Object[] state, String[] propertyNames, Type[] types) { // do nothing } public boolean onFlushDirty(Object entity, Serializable id, Object[] currentState, Object[] previousState, String[] propertyNames, Type[] types) { if ( entity instanceof Auditable ) { updates++; for ( int i=0; i < propertyNames.length; i++ ) { if ( "lastUpdateTimestamp".equals( propertyNames[i] ) ) { currentState[i] = new Date(); return true; } } } return false; } public boolean onLoad(Object entity, Serializable id, Object[] state, String[] propertyNames, Type[] types) { if ( entity instanceof Auditable ) { loads++; } return false; } public boolean onSave(Object entity, Serializable id, Object[] state, String[] propertyNames, Type[] types) { if ( entity instanceof Auditable ) { creates++; for ( int i=0; i<propertyNames.length; i++ ) { if ( "createTimestamp".equals( propertyNames[i] ) ) { state[i] = new Date(); return true; } } } return false; } public void afterTransactionCompletion(Transaction tx) { if ( tx.wasCommitted() ) { System.out.println("Creations: " + creates + ", Updates: " + updates, "Loads: " + loads); } updates=0; creates=0; loads=0; } }
拦截器可以有两种:Session范围内的，和SessionFactory范围内的。
当使用某个重载的SessionFactory.openSession()使用Interceptor作为参数调用打开一个session的时候，就指定了Session范围内的拦截器。
Session session = sf.openSession( new AuditInterceptor() );
或在配置文件中加:
<bean id="sessionFactory" class="cn.sh.cares.framework.spring.annotationSessionFactoryBean"> <property name="dataSource" ref="ppcDataSource"/> <!--<property name="lobHandler" ref="lobHandler"/>--> <property name="annotatedClassesLocations"> <list> <value>classpath*:</value> </list> </property>
<property name="hbmLocations"> <list> <value>classpath*:</value> </list> </property> <property name="hibernateProperties"> <props> <prop key="hibernate.dialect">cn.sh.cares.framework.dao.hibernate.OracleDialect</prop> <prop key="hibernate.format_sql">true</prop> <prop key="hibernate.show_sql">true</prop> <prop key="hibernate.use_sql_comments">false</prop> <prop key="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</prop> <prop key="hibernate.cache.use_query_cache">true</prop> <prop key="hibernate.cache.use_second_level_cache">true</prop> <prop key="hibernate.jdbc.batch_size">20</prop> <prop key="hibernate.jdbc.fetch_size">20</prop> </props> </property> <property name="entityInterceptor"> <bean id ="auditInterceptor" class="cn.sh.cares.framework.dao.hibernate.AuditInterceptor" /> </property>
本文转自：http://blog.csdn.net/pengchua/article/details/5013889
hibernate 中的拦截器EmptyInterceptor接口功能
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原文地址：http://www.cnblogs.com/dreammyle/p/4533391.html
