java学习笔记14--动态代理

InvocationHandler接口

[java] public interface InvocationHandler{
public Object invoke(Object proxy,Method method,Object[] args)throws Throwable
}

public interface InvocationHandler{
public Object invoke(Object proxy,Method method,Object[] args)throws Throwable
}
参数说明：

Object proxy：被代理的对象

Method method：要调用的方法

Object args[]：方法调用时所需要的参数

Proxy类

Proxy类是专门完成代理的操作类，可以通过此类为一个或多个接口动态地生成实现类，此类提供了如下的操作方法：

[java] public static Object newProxyInstance(ClassLoader loader,
            Class<?>[] interfaces,
            InvocationHandler h)
            throws IllegalArgumentException

public static Object newProxyInstance(ClassLoader loader,
   Class<?>[] interfaces,
   InvocationHandler h)
   throws IllegalArgumentException参数说明：

ClassLoader loader：类加载器

Class<?>[] interfaces：得到全部的接口

InvocationHandler h：得到InvocationHandler接口的子类实例

动态代理：

[java] package com.itmyhome;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

interface IHello{    //定义接口
    public void sayHello();
}
class HelloImpl implements IHello{

    @Override
    public void sayHello() {
        // TODO Auto-generated method stub
        System.out.println("hello itmyhome");
    }
}
class MyInvocationHandler implements InvocationHandler{

    private Object obj;   //真实主题类
    public Object bind(Object obj){
        this.obj = obj;
        return Proxy.newProxyInstance(obj.getClass().getClassLoader(), obj.getClass().getInterfaces(), this);
    }
    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        System.out.println("***before***");
        Object temp = method.invoke(obj, args);
        System.out.println("***after***");
        return temp;
    }
}

public class T {
    public static void main(String[] args) throws Exception{
        IHello h = (IHello)new MyInvocationHandler().bind(new HelloImpl());
        h.sayHello();
    }
}

package com.itmyhome;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

interface IHello{ //定义接口
public void sayHello();
}
class HelloImpl implements IHello{

@Override
public void sayHello() {
// TODO Auto-generated method stub
System.out.println("hello itmyhome");
}
}
class MyInvocationHandler implements InvocationHandler{

private Object obj;   //真实主题类
public Object bind(Object obj){
  this.obj = obj;
  return Proxy.newProxyInstance(obj.getClass().getClassLoader(), obj.getClass().getInterfaces(), this);
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
  System.out.println("***before***");
  Object temp = method.invoke(obj, args);
  System.out.println("***after***");
  return temp;
}
}

public class T {
public static void main(String[] args) throws Exception{
IHello h = (IHello)new MyInvocationHandler().bind(new HelloImpl());
h.sayHello();
}
}

补充：软件开发 , Java ,