4-02.AspectJ-基于注解的讲解

 

 

MyAspect.java

package com.exp.aspect;


import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.*;
import org.springframework.stereotype.Component;


@Component
@Aspect
public class MyAspect {
    //声明一个公共的切入点
    @Pointcut("execution(* com.exp.service.UserServiceImpl.*(..))")
    public void myPointcut(){}

    @Before("myPointcut()")
    public void myBefore(JoinPoint jp){
        System.out.println("1.前置通知..." + jp.getSignature().getName());//连接点方法名
    }

    /**
     * 后置通知获取service方法执行后的返回值
     * Object retValue:service方法执行的返回值,如果写了返回值，需要在xml中配置returning
     * @param jp
     */
    // <aop:after-returning method="myAfterReturning" pointcut-ref="myPointcut" returning="retValue"/>
    @AfterReturning(pointcut = "myPointcut()",returning = "retValue")
    public void myAfterReturning(JoinPoint jp,Object retValue){
        System.out.println("3.后置通知..." +  jp.getSignature().getName());
        System.out.println("返回值:" + retValue);
    }

    @Around("myPointcut()")
    public Object myAround(ProceedingJoinPoint pjp) throws Throwable {
        System.out.println("2.环绕通知...开启事务..." + pjp.getSignature().getName());
        //放行
        Object retObj = pjp.proceed();
        System.out.println("4.环绕通知....提交事务...");
        return retObj;
    }


    @AfterThrowing(pointcut = "myPointcut()",throwing = "e")
    public void myAfterThrowing(JoinPoint jp,Throwable e){
        System.out.println("异常通知..." + jp.getSignature().getName() + "===" + e.getMessage() );
    }

    @After("myPointcut()")
    public void myAfter(JoinPoint jp){
        System.out.println("最终通知..." + jp.getSignature().getName());
    }
}

 

bean02.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--xmlns xml namespace:xml命名空间-->
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:p ="http://www.springframework.org/schema/p"
       xmlns:context ="http://www.springframework.org/schema/context"
       xmlns:aop ="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                           http://www.springframework.org/schema/beans/spring-beans.xsd
                           http://www.springframework.org/schema/context
                           http://www.springframework.org/schema/context/spring-context.xsd
                           http://www.springframework.org/schema/aop
                           http://www.springframework.org/schema/aop/spring-aop.xsd">


    <!--  配置UserService-->
    <bean id="userService" class="com.exp.service.UserServiceImpl"></bean>

    <!-- 配置切面对象-->
    <bean id="myAspect" class="com.exp.aspect.MyAspect"></bean>

    <!-- 配置 aop -->
    <aop:config>
        <!-- aop:指定切面-->
        <aop:aspect ref="myAspect">
            <!--定义一个切入点-->
            <aop:pointcut id="myPointcut" expression="execution(* com.exp.service.UserServiceImpl.*(..))"/>

            <!-- 配置前置通知...-->
            <aop:before method="myBefore" pointcut-ref="myPointcut" />

            <!-- 配置后置通知...-->
            <aop:after-returning method="myAfterReturning" pointcut-ref="myPointcut" returning="retValue"/>

            <!--配置环绕通知-->
            <aop:around method="myAround" pointcut-ref="myPointcut"></aop:around>

            <!-- 配置异常通知
            throwing="e" 值，是方法的参数名
            -->
            <aop:after-throwing method="myAfterThrowing" pointcut-ref="myPointcut" throwing="e"/>

            <!--配置最终通知:不管有没有异常，最终通知都会执行-->
            <aop:after method="myAfter" pointcut-ref="myPointcut"></aop:after>
        </aop:aspect>
    </aop:config>
</beans>