笔记13 AOP中After和AfterReturning的区别

AOP中 @Before @After @AfterThrowing@AfterReturning的执行顺序

 public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
    Object result;
    try {
        //@Before
        result = method.invoke(target, args);
        //@After
        return result;
    } catch (InvocationTargetException e) {
        Throwable targetException = e.getTargetException();
        //@AfterThrowing
        throw targetException;
    } finally {
        //@AfterReturning
    }
 }

以Audience为例，代码如下：

 package concert;

 import org.aspectj.lang.annotation.After;
 import org.aspectj.lang.annotation.AfterReturning;
 import org.aspectj.lang.annotation.AfterThrowing;
 import org.aspectj.lang.annotation.Aspect;
 import org.aspectj.lang.annotation.Before;
 import org.aspectj.lang.annotation.Pointcut;
 import org.springframework.stereotype.Component;

 @Aspect
 @Component
 public class Audience {
     @Pointcut("execution(* concert.Performance.perform(..))")
     public void performs() {

     }

     @Before("performs()")
     public void silenceCellPhones() {
         System.out.println("Silencing cell phone");
     }

     @Before("performs()")
     public void takeSeats() {
         System.out.println("Taking seats");
     }

     @After("performs()")
     public void after() {
         System.out.println("after");
     }

     @AfterReturning("performs()")
     public void applause() {
         System.out.println("CLAP CLAP CLAP");
     }

     @AfterThrowing("performs()")
     public void demandRefund() {
         System.out.println("Demanding a refund");
     }
 }

执行结果：

注入AspectJ切面 （新）

1.将原来的观众类定义为一个真正的切面，Audience.java 将观众的行为都放在这个切面中，然后在spring中引用这个切面，并且为这个切面注入新的方法，具体可参照笔记12。

 package concert4;

 public aspect Audience {
     public Audience(){}
     pointcut performance():execution(* perform(..));

     before():performance(){
         System.out.println("Silencing cell phone");
     }
     before():performance(){
         System.out.println("Taking seats");
     }
     after():performance(){
         System.out.println("CLAP CLAP CLAP");
     }
     after()returning :performance(){
         System.out.println("--------------评论----------------");
         System.out.println(criticismEngine.getCriticism());
         System.out.println("----------------------------------");
     }

     private CriticismEngine criticismEngine;

     public void setCriticismEngine(CriticismEngine criticismEngine){
         this.criticismEngine=criticismEngine;
     }
 }

2.修改XML配置文件

 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns:aop="http://www.springframework.org/schema/aop"
     xmlns:tx="http://www.springframework.org/schema/tx"
     xmlns:context="http://www.springframework.org/schema/context"
     xmlns:c="http://www.springframework.org/schema/c"
     xsi:schemaLocation="
    http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
    http://www.springframework.org/schema/aop
    http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
    http://www.springframework.org/schema/tx
    http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-3.0.xsd">

            <bean class="concert4.Classcial"></bean>
         <bean id="criticismEngine" class="concert4.CriticismEngineTmpl">
             <property name="criticismPool">
                 <list>
                     <value>不好</value>
                     <value>很不好</value>
                     <value>非常不好</value>
                 </list>
             </property>
         </bean>
         <bean id="audience" class="concert4.Audience" factory-method="aspectOf">
             <property name="criticismEngine" ref="criticismEngine"></property>
         </bean>
             <aop:config>
                    <aop:aspect ref="audience">
                        <aop:declare-parents types-matching="concert4.Performance+"
                                             implement-interface="concert4.Encoreable"
                                             default-impl="concert4.DefaultEncoreable"/>
                    </aop:aspect>
            </aop:config>

    </beans>

3.结果