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