静态代理和动态代理

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一、代理模式

代理设计就是为其他对象提供一种代理以控制对这个对象的访问

二、静态代理

工厂接口

interface ClothFactory {
    public void produceCloth();
}

被代理类

class NikeClothProduct implements ClothFactory{
    @Override
    public void produceCloth() {
        System.out.println("生产Nike服装");
    }
}

代理类

class ProxyClothFactory implements ClothFactory{
    private ClothFactory clothProduct;

    public ProxyClothFactory(ClothFactory clothProduct) {
        this.clothProduct = clothProduct;
    }

    @Override
    public void produceCloth() {
        System.out.println("生产前工作");
        clothProduct.produceCloth();
        System.out.println("生产后工作");
    }
}

主函数驱动测试

public class ClothProxyTest {
    public static void main(String[] args) {
        NikeClothProduct nikeClothProduct = new NikeClothProduct();
        ProxyClothFactory proxyClothFactory = new ProxyClothFactory(nikeClothProduct);
        proxyClothFactory.produceCloth();
    }
}

运行结果

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三、动态代理

实现Invocation类，加入通用方法

class MyInvocationHandler implements InvocationHandler{
	//用于保存被代理类对象
    private Object obj;
    public void band(Object obj){
        this.obj = obj;
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        //===============前置通用方法===========
        System.out.println("=============前置方法=============");
        //=====================================
        
        //===============原始方法==============
        Object returnVal = method.invoke(obj,args);
        //=====================================
       
        //===============后置通用方法===========
        System.out.println("=============后置方法=============");
        //=====================================
        return returnVal;
    }
}

通过Proxy类创建动态代理对象

先绑定被代理类
返回Proxy.newProxyInstance(被代理类的类加载器，被代理类的接口，InvocationHandler对象)

将其写入ProxyFactory代理类中

class ProxyFactor{
    public static Object getProxyInstance(Object obj){
        MyInvocationHandler handler = new MyInvocationHandler();
        handler.band(obj);
        return Proxy.newProxyInstance(obj.getClass().getClassLoader(), obj.getClass().getInterfaces(), handler);
    }
}

使用

public class DynamicProxyTest {
    public static void main(String[] args) {
        SuperMan superMan = new SuperMan();
        //载入任何对象
        Human proxy = (Human) ProxyFactor.getProxyInstance(superMan);
        //调用任何对象的方法都会先使用代理类方法
        System.out.println(proxy.getBelief());
        proxy.eat("麻辣烫");
    }
}

总结

difficult