前置增强的实现

1.创建一个接口类

public interface Waiter {

 void greetTo(String name);

 void serveTo(String name);

}

2.创建接口实现类

public class NaiveWaiter implements Waiter {

 @Override

 public void greetTo(String name) {

  System.out.println("greet to "+name+"...");

 }

 @Override

 public void serveTo(String name) {

  System.out.println("serving "+name+"...");

 }

}

4.实现前置增强接口

public class GreetingBeforAdvice implements MethodBeforeAdvice {

 /**

  * method 为目标类的方法

  *

  * args 为目标类的入参

  *

  * obj 为目标类的实例

  */

 @Override

 public void before(Method method, Object[] args, Object target)

   throws Throwable {

  String clientName = (String) args[0];

  System.out.println("How are you! Mr " + clientName + ".");

  // System.out.println(target.getClass().getName());

 }

}
5.advisor 上场

public class TestBeforAdvice {

 

 public static void main(String[] args) {

  Waiter target=new NaiveWaiter();

 

  BeforeAdvice beforeAdvice=new GreetingBeforAdvice();

 

  //spring 提供的代理工厂

  ProxyFactory pf=new ProxyFactory();

  //设置代理目标

  pf.setTarget(target);

  //为代理目标添加增强

  pf.addAdvice(beforeAdvice);

  //生成代理实例

  Waiter waiter=(Waiter) pf.getProxy();

  waiter.greetTo("John");

  waiter.serveTo("Tom");

 }

}

main方法运行结果：