Java 代理

静态代理

//接口
public interface ProxyFunc {
    public void request(); //对需要代理的每个方法，都需要进行静态编码，简洁但繁琐
}

//目标对象
public class Client implements ProxyFunc {
    @Override
    public void request() {
        System.out.println("hello world");
 }
}

//代理对象
public class Proxyer implements ProxyFunc {
    private ProxyFunc proxyFunc;
    public Proxyer(ProxyFunc proxyFunc) {
        this.proxyFunc = proxyFunc;
 }
    @Override
    public void request() {
        System.out.println("在访问目标对象前，做一些控制处理");
        proxyFunc.request();
        System.out.println("在访问目标对象后，做一些控制处理");
    }
    public static void main(String[] args) {
        Client client = new Client();
        Proxyer proxyer = new Proxyer(client);
        proxyer.request();
    }
}

jdk动态代理

//接口
public interface Interface {
    public void hello1();
    public void hello2();
}

//被代理对象
public class Target implements Interface{
    @Override
    public void hello1() {
        System.out.println("hello world1");
    }
    @Override
    public void hello2() {
        System.out.println("hello world2");
    }
}

//代理处理器
public class Handler implements InvocationHandler {
    private Interface mInterface;
    public Handler(Interface mInterface) {
        this.mInterface = mInterface;
    }
    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        System.out.println("调用前处理");
        Object result =  method.invoke(mInterface, args);
        System.out.println("调用后处理");
        return result;
    }
}

//测试
public class Test {
    public static void main(String[] args) {
        Target target = new Target();
        Handler handler = new Handler(target);
        Interface proxyer = (Interface) Proxy.newProxyInstance(target.getClass().getClassLoader(), target.getClass().getInterfaces(), handler);
        proxyer.hello1();
        proxyer.hello2();
    }
}