java中的代理

package cn.itcast.day3;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.ArrayList;
import java.util.Collection;

public class ProxyTest {

 /**
  * @param args
  */
 public static void main(String[] args) throws Exception {
  // TODO Auto-generated method stub
  Class clazzProxy1 = Proxy.getProxyClass(Collection.class.getClassLoader(), Collection.class);
  System.out.println(clazzProxy1.getName());

  System.out.println("----------begin constructors list----------");
  /*
   * $Proxy0() $Proxy0(InvocationHandler,int)
   */
  Constructor[] constructors = clazzProxy1.getConstructors();
  for (Constructor constructor : constructors) {
   String name = constructor.getName();
   StringBuilder sBuilder = new StringBuilder(name);
   sBuilder.append('(');
   Class[] clazzParams = constructor.getParameterTypes();
   for (Class clazzParam : clazzParams) {
    sBuilder.append(clazzParam.getName()).append(',');
   }
   if (clazzParams != null && clazzParams.length != 0)
    sBuilder.deleteCharAt(sBuilder.length() - 1);
   sBuilder.append(')');
   System.out.println(sBuilder.toString());
  }

  System.out.println("----------begin methods list----------");
  /*
   * $Proxy0() $Proxy0(InvocationHandler,int)
   */
  Method[] methods = clazzProxy1.getMethods();
  for (Method method : methods) {
   String name = method.getName();
   StringBuilder sBuilder = new StringBuilder(name);
   sBuilder.append('(');
   Class[] clazzParams = method.getParameterTypes();
   for (Class clazzParam : clazzParams) {
    sBuilder.append(clazzParam.getName()).append(',');
   }
   if (clazzParams != null && clazzParams.length != 0)
    sBuilder.deleteCharAt(sBuilder.length() - 1);
   sBuilder.append(')');
   System.out.println(sBuilder.toString());
  }

  System.out.println("----------begin create instance object----------");
  // Object obj = clazzProxy1.newInstance();
  Constructor constructor = clazzProxy1.getConstructor(InvocationHandler.class);
  class MyInvocationHander1 implements InvocationHandler {

   public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
    // TODO Auto-generated method stub
    return null;
   }

  }
  Collection proxy1 = (Collection) constructor.newInstance(new MyInvocationHander1());

  System.out.println(proxy1);
  proxy1.clear();
  // proxy1.size();
  // System.out.println("111111111111111");

  Collection proxy2 = (Collection) constructor.newInstance(new InvocationHandler() {

   public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
    return null;
   }

  });

  final ArrayList target = new ArrayList();
  Collection proxy3 = (Collection) getProxy(target, new MyAdvice());
  proxy3.add("zxx");
  proxy3.add("lhm");
  proxy3.add("bxd");
  System.out.println(proxy3.size());
  System.out.println(proxy3.getClass().getName());
 }

 private static Object getProxy(final Object target, final Advice advice) {
  Object proxy3 = Proxy.newProxyInstance(target.getClass().getClassLoader(),
  /* new Class[]{Collection.class}, */
  target.getClass().getInterfaces(), new InvocationHandler() {

   public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {

    /*
     * long beginTime = System.currentTimeMillis(); Object retVal =
     * method.invoke(target, args); long endTime =
     * System.currentTimeMillis();
     * System.out.println(method.getName() + " running time of " +
     * (endTime - beginTime)); return retVal;
     */

    advice.beforeMethod(method);
    Object retVal = method.invoke(target, args);
    advice.afterMethod(method);
    return retVal;

   }
  });
  return proxy3;
 }

}

----------------------------------------------------------------------------

package cn.itcast.day3;

import java.lang.reflect.Method;

public interface Advice {
 void beforeMethod(Method method);
 void afterMethod(Method method);
}
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package cn.itcast.day3;

import java.lang.reflect.Method;

public class MyAdvice implements Advice {
 long beginTime = 0;

 public void afterMethod(Method method) {
  // TODO Auto-generated method stub
  System.out.println("调用方法后做的事！");  
  long endTime = System.currentTimeMillis();
  System.out.println(method.getName() + " running time of " + (endTime - beginTime));

 }

 public void beforeMethod(Method method) {
  // TODO Auto-generated method stub
  System.out.println("调用方法前做的事！");
  beginTime = System.currentTimeMillis();
 }

}