Spring学习笔记 2007-10-28 Spring实现代理机制

Spring学习笔记 2007-10-28 Spring实现代理机制

上一笔记，介绍了代理机制，这一节介绍Spring是如何实现代理。
通过一个例子来说明。
包下载地址：
http://www.ziddu.com/download/3555992/SpringAndaop.rar.html

(1)创建LogBeforeAdvice类(实现MethodBeforeAdvice接口，会在目标对象的方法执行之前被呼叫)

package com.proxy;

import java.lang.reflect.*;
import java.util.logging.Logger;
import java.util.logging.Level;
import org.springframework.aop.MethodBeforeAdvice;;

public class LogBeforeAdvice  implements MethodBeforeAdvice{

 private Logger logger=Logger.getLogger(this.getClass().getName());
 public void before(Method method,Object[] args,Object target) throws Throwable
 {
  logger.log(Level.INFO,"mehtod starts "+method);
 }
}

(2)创建配置文件advice-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">

<beans>
 <bean id="logBeforeAdvice" class="com.proxy.LogBeforeAdvice" />
 <bean id="helloSpeaker" class="com.proxy.HelloSpeaker" />
 
 <bean id="helloProxy"
  class="org.springframework.aop.framework.ProxyFactoryBean"><!--建立代理对象-->
  <property name="proxyInterfaces"><!--代理接口-->
   <value>com.proxy.IHello</value>
  </property>
  <property name="target"><!--代理目标-->
   <ref bean="helloSpeaker" />
  </property>
  <property name="interceptorNames"><!--代理实现类-->
   <list>
    <value>logBeforeAdvice</value>
   </list>
  </property>
 </bean>
 
</beans>
(3)测试类SpringAOPDemo

package com.proxy;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.FileSystemXmlApplicationContext;

public class SpringAOPDemo {
 public static void main(String[] args)
 {
  //读取配置文件
  ApplicationContext context=new FileSystemXmlApplicationContext("advice-config.xml");
  IHello helloProxy=(IHello)context.getBean("helloProxy");
  helloProxy.hello("ducklyl");
  
 }
}

运行测试类，结果如下：
Hello,ducklyl