动态代理

package com.fgy.proxy;

public interface SaleComputer {
    String sale(Double money);

    void show(Double money);
}

package com.fgy.proxy;

public class Lenovo implements SaleComputer {
    @Override
    public String sale(Double money) {
        System.out.println("联想电脑卖" + money + "元。");
        return "联想电脑";
    }

    @Override
    public void show(Double money) {
        System.out.println("联想电脑，价格：" + money);
    }
}

package com.fgy.proxy;

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

/**
 * 动态代理测试
 */
public class ProxyTest {
    public static void main(String[] args) {
        // 1.创建真实对象
        Lenovo lenovo = new Lenovo();
        // 2.动态代理增强lenovo
        SaleComputer proxy_lenovo = (SaleComputer) Proxy.newProxyInstance(lenovo.getClass().getClassLoader(), lenovo.getClass().getInterfaces(), new InvocationHandler() {
            @Override
            public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                if (method.getName().equals("sale")) {
                    System.out.println("专车接送：");
                    double money = (double) args[0] * 1.25;
                    String obj = (String) method.invoke(lenovo, money);
                    System.out.println("免费送货。");
                    return obj + "_送鼠标垫";
                } else {
                    Object obj = method.invoke(lenovo, args);
                    return obj;
                }
            }
        });

        // 3.调用方法
        String computer = proxy_lenovo.sale(10000.99);
        System.out.println(computer);
        // proxy_lenovo.show(8000.99);
    }
}