代理模式

public interface CoverProxyInterface {
    String eat(String str);

    String sleep(String str);
}

public class CoverProxyClass implements CoverProxyInterface {
    @Override
    public String eat(String str) {
        return str;
    }

    @Override
    public String sleep(String str) {
        return str;
    }
}

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

public class ProxyPractice {
    public static void main(String[] args) {
        CoverProxyInterface cpc = new CoverProxyClass();

        CoverProxyInterface proxy = (CoverProxyInterface) Proxy.newProxyInstance(cpc.getClass().getClassLoader(), cpc.getClass().getInterfaces(), new InvocationHandler() {
            @Override
            public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                if ("eat".equals(method.getName())) {
                    args[0] = "我 " + args[0];
                    String res = (String) method.invoke(cpc, args);
                    res = res + " 大西瓜";
                    return res;
                } else if ("sleep".equals(method.getName())) {
                    args[0] = "你 " + args[0];
                    String res = (String) method.invoke(cpc, args);
                    res = res + " 大软床";
                    return res;
                } else {
                    return null;
                }
            }
        });

        String eat = proxy.eat("吃");
        System.out.println(eat);
        String sleep = proxy.sleep("睡");
        System.out.println(sleep);
    }
}