Spring基於XML配置AOP

目錄結構：

D:\Java\IdeaProjects\JavaProj\SpringHelloWorld\src\cn\edu\bjut\service\StudentService.java

package cn.edu.bjut.service;

/**  * Created by N3verL4nd on 2017/3/24.  */ public interface StudentService {
    public void addStudent(String name);
}

D:\Java\IdeaProjects\JavaProj\SpringHelloWorld\src\cn\edu\bjut\service\impl\StudentServiceImpl.java

package cn.edu.bjut.service.impl;

import cn.edu.bjut.service.StudentService;

/**  * Created by N3verL4nd on 2017/3/24.  */ public class StudentServiceImpl implements StudentService {
    @Override
    public void addStudent(String name) {
        System.out.println("[添加學生]：" + name);
        //觸發異常通知
//        System.out.println( 1 / 0);
    }
}

D:\Java\IdeaProjects\JavaProj\SpringHelloWorld\src\cn\edu\bjut\advice\StudentServiceAspect.java

package cn.edu.bjut.advice;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;

import java.util.Arrays;

/**  * Created by N3verL4nd on 2017/3/24.  */ public class StudentServiceAspect {

    //前置通知
    public void doBefore(JoinPoint jp) {
        System.out.println("--------------前置通知-------------");
        System.out.println("類名：" + jp.getTarget().getClass().getName());
        System.out.println("方法名：" + jp.getSignature().getName());
        System.out.println("開始添加學生：" + Arrays.toString(jp.getArgs()));
        System.out.println("-----------------------------------");
    }

    //後置通知
    public void doAfter(JoinPoint jp) {
        System.out.println("--------------後置通知-------------");
        System.out.println("學生添加完成!");
        System.out.println("-----------------------------------");
    }

    //環繞通知
    public Object doAround(ProceedingJoinPoint pjp) throws Throwable {
        System.out.println("--------------環繞通知-------------");
        System.out.println("添加學生前：");
        Object retVal = null;
        retVal= pjp.proceed();
        System.out.println("返回值：" + retVal);
        System.out.println("添加學生後!");
        System.out.println("-----------------------------------");
        return retVal;
    }

    //返回通知
    public void doAfterReturning(JoinPoint jp) {
        System.out.println("--------------返回通知-------------");
        System.out.println("-----------------------------------");
    }

    //異常通知
    public void doAfterThrowing(JoinPoint jp, Throwable ex) {
        System.out.println("--------------異常通知-------------");
        System.out.println("異常信息：" + ex.getMessage());
        System.out.println("-----------------------------------");
    }
}

D:\Java\IdeaProjects\JavaProj\SpringHelloWorld\src\cn\edu\bjut\test\T.java

package cn.edu.bjut.test;

import cn.edu.bjut.service.StudentService;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**  * Created by N3verL4nd on 2017/3/24.  */ public class T {
    private ApplicationContext context = null;

    @Before
    public void setUp() {
        context = new ClassPathXmlApplicationContext("beans.xml");
    }

    @Test
    public void test() {
        StudentService studentService = (StudentService) context.getBean("studentService");
        studentService.addStudent("lgh");
    }
}

D:\Java\IdeaProjects\JavaProj\SpringHelloWorld\src\beans.xml

<?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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">

    <bean id="studentServiceAspect" class="cn.edu.bjut.advice.StudentServiceAspect"/>

    <bean id="studentService" class="cn.edu.bjut.service.impl.StudentServiceImpl"/>

    <aop:config>
        <aop:aspect ref="studentServiceAspect">
            <aop:pointcut id="businessService" expression="execution(public void cn.edu.bjut.service.impl.StudentServiceImpl.addStudent(String))"/>
            <aop:before method="doBefore" pointcut-ref="businessService"/>
            <aop:after method="doAfter" pointcut-ref="businessService"/>
            <aop:around method="doAround" pointcut-ref="businessService"/>
            <aop:after-returning method="doAfterReturning" pointcut-ref="businessService"/>
            <aop:after-throwing method="doAfterThrowing" pointcut-ref="businessService" throwing="ex"/>
        </aop:aspect>
    </aop:config>
</beans>

輸出：

--------------前置通知-------------
類名：cn.edu.bjut.service.impl.StudentServiceImpl
方法名：addStudent
開始添加學生：[lgh]
-----------------------------------
--------------環繞通知-------------
添加學生前：
[添加學生]：lgh
--------------返回通知-------------
-----------------------------------
返回值：null
添加學生後!
-----------------------------------
--------------後置通知-------------
學生添加完成!
-----------------------------------

介紹一下org/aspectj/lang/JoinPoint.java

AspectJ使用org.aspectj.lang.JoinPoint接口表示目標類鏈接點對象，若是是環繞加強時，使用org.aspectj.lang.ProceedingJoinPoint表示鏈接點對象，該類是JoinPoint的子接口。

任何一個加強方法均可以經過將第一個入參聲明爲JoinPoint訪問到鏈接點上下文的信息。咱們先來了解一下這兩個接口的主要方法： 

1)JoinPoint 
java.lang.Object[] getArgs()：獲取鏈接點方法運行時的入參列表； 
Signature getSignature() ：獲取鏈接點的方法簽名對象； 
java.lang.Object getTarget() ：獲取鏈接點所在的目標對象； 
java.lang.Object getThis() ：獲取代理對象自己； 
2)ProceedingJoinPoint 
ProceedingJoinPoint繼承JoinPoint子接口，它新增了兩個用於執行鏈接點方法的方法： 
java.lang.Object proceed() throws java.lang.Throwable：經過反射執行目標對象的鏈接點處的方法； 
java.lang.Object proceed(java.lang.Object[] args) throws java.lang.Throwable：經過反射執行目標對象鏈接點處的方法，不過使用新的入參替換原來的入參。