动态代理

1：利用反射机制在运行时创建代理类

package com.wing.mall.base.proxy;

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

/**
 * <p>
 *     利用反射机制在运行时创建代理类
 * </p>
 *
 * @author: heluwei
 * @Date: 2020/4/15 10:51
 */
public class ProxyHandler implements InvocationHandler {
    private Object object;
    public ProxyHandler(Object object){
        this.object = object;
    }
    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        System.out.println("Before invoke "  + method.getName());
        method.invoke(object, args);
        System.out.println("After invoke " + method.getName());
        return null;
    }

}

2：创建目标类

package com.wing.mall.base.proxy;

public interface ByeInterface {
    void sayBye();
}

package com.wing.mall.base.proxy;

/**
 * <p></p>
 *
 * @author: heluwei
 * @Date: 2020/4/15 10:53
 */
public class Bye implements ByeInterface {
    @Override
    public void sayBye() {
        System.out.println("Bye 张三!");
    }
}

使用：

public static void main(String[] args) {
        Bye bye = new Bye();
        InvocationHandler  proxyHandler = new ProxyHandler(bye);
        ByeInterface byeProxy = (ByeInterface)Proxy.newProxyInstance(bye.getClass().getClassLoader(), bye.getClass().getInterfaces(), proxyHandler);
        byeProxy.sayBye();
    }

输出：