JDK动态代理

• 一个动态代理的实例

package com;

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

/** * @author doggy * Created on 16-7-3. */
public class Test {
    public static void main(String[] args){
        AI ai = new AI();
        AP ap = new AP();
        A a = (A)ap.bind(ai);
        System.out.println(a.getClass());
        a.p();

    }
}
interface A{
    void p();
}
class AI implements A{
    @Override
    public void p() {
        System.out.println("I am AI.");
    }
}
class AP implements InvocationHandler{
    private Object target;
    public Object bind(Object o){
        this.target = o;
        return Proxy.newProxyInstance(target.getClass().getClassLoader(),target.getClass().getInterfaces(),this);
    }
    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        System.out.println("proxyed");
        return method.invoke(target,args);
    }
}

JDK的动态代理做了什么?

1. Proxy.newProxyInstance()会先根据传进去的接口和类加载器,创建一个代理类.
2. 根据InvocationHandler实例创建一个代理类的实例.