Java动态代理模拟struts2拦截器原理

①TargetInterface

package com.hzp.interceptor;
//目标对象接口
public interface TargetInterface {
 public void doSomething();
}

 

②Target

package com.hzp.interceptor;
//目标对象
public class Target implements TargetInterface {
 public void doSomething() {
  System.out.println("doSomething");
 }
 
}


③MyProxy

package com.hzp.interceptor;
import java.lang.reflect.Proxy;
//动态代理类
public class MyProxy {
 public Object getProxy(Object o){
  Handler handler=new Handler();
  handler.setObject(o);
  return Proxy.newProxyInstance(Target.class.getClassLoader(),o.getClass().getInterfaces(),handler);
 }
}


④Interceptor

package com.hzp.interceptor;
//拦截器
public class Interceptor {
 public void before(){
  System.out.println("before");
 }
 
 public void after(){
  System.out.println("after");
 }
}


⑤Handler

package com.hzp.interceptor;
//处理类
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;

public class Handler implements InvocationHandler {
 
 private Object object;
 private Interceptor interceptor=new Interceptor();
 public void setObject(Object o){
  this.object=o;
 }

 public Object invoke(Object proxy, Method method, Object[] args)
   throws Throwable {
  
  Object result= null;
  interceptor.before();
  method.invoke(object, args);
  interceptor.after();
  return result;
 }

}


⑥Client

package com.hzp.interceptor;
//测试类
public class Client {
 public static void main(String[] args){
  TargetInterface target=new Target();
  MyProxy myProxy=new MyProxy();
  TargetInterface proxy=(TargetInterface)myProxy.getProxy(target);
  proxy.doSomething();
 }
}