Java Proxy.newProxyInstance动态代理

2021-01-02 18:15:22 666

定义接口

public interface Student {
	 void buy();

	 String talk();
}

实现类

public class Lisi implements Student {
	@Override
	public void buy() {
		System.out.println("买");
		
	}
 
	@Override
	public String talk() {
	    System.out.println("说");
            return "说"
	}
}

代理类 实现InvocationHandler

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
 
public class MyInvocation implements InvocationHandler {
	private Object obj;
 
	public MyInvocation(Object obj) {
		this.obj = obj;
	}
 
	@Override
	public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        if (method.getName().equals("talk")) {
            System.out.println("增强方法");
            method.invoke(obj, args);
            return "说";
        }
        return method.invoke(obj, args);
	}
 
}

测试

import java.lang.reflect.Proxy;
 
public class Test {
	public static void main(String[] args) {
		Lisi s=new Lisi();
		MyInvocation my=new MyInvocation(s);
        //参数一：Lisi类的类加载器
        //参数二：Lisi实现的所有接口
        //参数三：实现了invocationHandler接口的对象
		Student lisi= (Student) Proxy.newProxyInstance(s.getClass().getClassLoader(), s.getClass().getInterfaces(), my);
  
		lisi.buy();
		System.out.println(lisi.talk());
	}
}

• java