jdk动态代理 案例

 

 

 

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
interface Person1 {
    public String eat();
    public String drink();
}
class Kid implements Person1{
    public String name;
    public Kid(String name) {
        this.name=name;
    }
    public String eat() {
        System.out.println("kids are eating!");
        return this.name;
    }
    public String drink() {
        System.out.println("kids are drinking!");
        return this.name;
    }
    
}
class MyInvocationHandler<T> implements InvocationHandler{
    //被代理对象
    private T target;
    public MyInvocationHandler(T target){
        this.target=target;
    }
    /**
     * 
     */
    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        Object result;
        if("eat".equals(method.getName())) {
            System.out.println("洗手");
            result = method.invoke(target, args);
            System.out.println("刷碗");
        }else {
            result = method.invoke(target, args);
        }
        return result;    //反射方法的返回值
    }
    
}
public class ProxyDemos {
    public static void main(String[] args) throws NoSuchMethodException, SecurityException, Throwable {
        Person1 p=new Kid("小王");
        MyInvocationHandler<Person1> handle=new MyInvocationHandler<Person1>(p);
        Person1 kid=(Person1) Proxy.newProxyInstance(Person1.class.getClassLoader(), new Class<?>[]{Person1.class}, handle);
        System.out.println(kid.eat());
        System.out.println("--------------------");
        System.out.println(kid.drink());
    }
}
Output:

洗手
kids are eating!
刷碗
小王
--------------------
kids are drinking!
小王