Java动态代理中报java.lang.IllegalArgumentException非法参数异常

今天在学习动态代理,在调试的过程中出现了非法参数异常的问题,先看下异常:

Exception in thread "main" java.lang.IllegalArgumentException: object is not an instance of declaring class
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.test.Application.WorkHandler.invoke(WorkHandler.java:24)
    at com.sun.proxy.$Proxy0.time(Unknown Source)
    at com.test.Application.Test.main(Test.java:18)

后来发下原来是我把代理调用处理程序用调用真实对象方法的时候invoke方法的第一个参数写成了method,应该写真实的代理对象:

//错误的写法
method.invoke(method, args);

正确的写法如下:

package com.test.Application;

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

public class WorkHandler implements InvocationHandler{

    private Object obj;

    public WorkHandler(Object obj) {
        this.obj = obj;
    }
    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        System.out.println("before 动态代理...");
        System.out.println(proxy.getClass().getName());
        System.out.println(this.obj.getClass().getName());
        if(method.getName().equals("work")) {
            method.invoke(this.obj, args);
            System.out.println("after 动态代理...");
            return proxy;
        } else {
            System.out.println("after 动态代理...");
            return method.invoke(this.obj, args);
        }
    }

}

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转载自blog.csdn.net/yaomingyang/article/details/81041111