Java静态代理和动态代理

╰+攻爆jí腚メ 2023-07-25 09:11 11阅读 0赞

静态代理：

//接口
    interface ClothFactory{
        
        void produce();
    }
    //被代理类
    class Adidas implements ClothFactory{
        
        @Override
        public void produce() {
        
            System.out.println("我生产了一双Adidas运动鞋");
        }
    }
    //代理类
    class StaticProxyFactory implements ClothFactory{
        
    
        private  ClothFactory proxyClothFactory;
    
        public StaticProxyFactory(ClothFactory proxyClothFactory) {
        
            this.proxyClothFactory = proxyClothFactory;
        }
    
        @Override
        public void produce() {
        
            System.out.println("开始代理");
            proxyClothFactory.produce();
            System.out.println("代理结束");
        }
    }
    public class StaticProxy {
        
        public static void main(String[] args) {
        
            Adidas adidas = new Adidas();
            StaticProxyFactory staticProxyFactory = new StaticProxyFactory(adidas);
            staticProxyFactory.produce();
        }
    }

动态代理：

import java.lang.reflect.InvocationHandler;
    import java.lang.reflect.Method;
    import java.lang.reflect.Proxy;
    
    interface Singer{
        
        String getName();
        void sing(String singName);
    }
    //被代理类
    class Adele implements Singer{
        
    
        @Override
        public String getName() {
        
            return "Adele";
        }
    
        @Override
        public void sing(String singName) {
        
            System.out.println("我唱了一首" + singName);
        }
    
    }
    /*
    实现动态代理需要解决两个问题
    一：根据加载到内存中的被代理类。动态的创建一个代理类及对象
    二：通过被代理类的对象的同名方法，调用被代理类的方法
     */
    //这个类提供了一个返回代理类对象的方法，简化操作
    class ProxyFactory{
        
    
        /**
         * 调用此方法返回一个代理类的对象，解决问题一
         * @param obj 被代理类的对象
         * @return 代理类的对象
         */
        public static Object getProxyInstance(Object obj){
        
            MyInvocationHandler handler = new MyInvocationHandler();
            handler.bind(obj);
            return Proxy.newProxyInstance(obj.getClass().getClassLoader(),obj.getClass().getInterfaces(),handler);
        }
    }
    class MyInvocationHandler implements InvocationHandler{
        
    
        //被代理类的对象
        private Object obj;
    
        public void bind(Object obj){
        
            this.obj = obj;
        }
        //当调用代理类对象的方法a时，就会自动调用如下的方法,不需要主动调用
        @Override
        public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        
            return method.invoke(obj,args);
        }
    }
    public class DynamicProxy {
        
    
        public static void main(String[] args) {
        
    
            Adele adele = new Adele();
            Singer proxyInstance = (Singer) ProxyFactory.getProxyInstance(adele);
            System.out.println(proxyInstance.getName());
            proxyInstance.sing("Hello");
    
    
            Adidas adidas = new Adidas();
            ClothFactory proxyInstance1 = (ClothFactory) ProxyFactory.getProxyInstance(adidas);
            proxyInstance1.produce();
        }
    }