spring aop的五大通知类

大家好，又见面了，我是你们的朋友全栈君。

spring aop通知(advice)分成五类：

• 前置通知[Before advice]@Before：在连接点前面执行，前置通知不会影响连接点的执行，除非此处抛出异常。
• 后置通知、正常返回通知[After returning advice]@AfterReturning：在连接点正常执行完成后执行，如果连接点抛出异常，则不会执行；与环绕通知同时使用时，会受环绕通知的影响。
• 异常通知、异常返回通知[After throwing advice]@AfterThrowing：在连接点抛出异常后执行。
• 最终通知、返回通知[After (finally) advice]@After：在连接点执行完成后执行，不管是正常执行完成，还是抛出异常，都会执行返回通知中的内容。
• 环绕通知[Around advice]@Around：环绕通知围绕在连接点前后，比如一个方法调用的前后。这是最强大的通知类型，能在方法调用前后自定义一些操作。环绕通知还需要负责决定是继续处理join point(调用ProceedingJoinPoint的proceed方法)还是中断执行。
  
  pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>groupId</groupId>
    <artifactId>dome03</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.1.5.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>commons-logging</groupId>
            <artifactId>commons-logging</artifactId>
            <version>1.2</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>5.1.5.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
            <version>3.1</version>
        </dependency>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.2</version>
        </dependency>
    </dependencies>
    
</project>

applicationContext.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:context="http://www.springframework.org/schema/context" xmlns:aop="http://www.springframework.org/schema/aop" xsi:schemaLocation=" http://www.springframework.org/schema/aop https://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd">

    <context:component-scan base-package="com.xbj"/>
    <aop:config proxy-target-class="true">
        <aop:aspect ref="myAdvices">
            <aop:pointcut id="pc" expression="execution(* com.xbj.service.impl.*.*(..))"/>
            <aop:before method="before" pointcut-ref="pc" />
            <aop:after-returning method="afterRunturn" pointcut-ref="pc" />
            <aop:after method="afterfinally" pointcut-ref="pc" />
            <aop:around method="around" pointcut-ref="pc" />
            <!--ex 要和 切面的 参数签名一致-->
            <aop:after-throwing method="afterThorw" pointcut-ref="pc" throwing="ex" />
        </aop:aspect>
    </aop:config>
</beans>

UserController.java

package com.xbj.controller;

import com.xbj.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;

/** * @Author:晓宇码匠 * @Date：2019/6/15 0015 */
/* @Controller @Repository @Component @Service 都是将bean放入Ioc容器中，只是为了代码的可读性而去区别开 * @Autowired 是从Ioc容器拿对象 * */
@Controller
public class UserController { 
   

    @Autowired
    private UserService userService;

    public void addUser(){ 
   
        userService.addUser();
    }
}

UserDao.java

package com.xbj.dao;

/** * @Author:晓宇码匠 * @Date：2019/6/15 0015 */
 public interface UserDao { 
   
    void addUser();
    void delUser();
}

UserDaoImpl.java

package com.xbj.dao.impl;

import com.xbj.dao.UserDao;
import org.junit.runner.RunWith;
import org.springframework.stereotype.Repository;
import org.springframework.stereotype.Service;

/** * @Author:晓宇码匠 * @Date：2019/6/15 0015 */
@Repository
public class UserDaoImpl implements UserDao { 
   
    public void addUser() { 
   
        System.out.println("addUser");
    }

    public void delUser() { 
   
        System.out.println("delUser");
    }

    //定义初始化方法
    public void myInit(){ 
   
        System.out.println("init...");

    }
    //定义销毁方法
    public void dest(){ 
   
        System.out.println("dest...");
    }

}

UserService.java

package com.xbj.service;

/** * @Author:晓宇码匠 * @Date：2019/6/15 0015 */
public interface UserService { 
   
    void addUser();
    void delUser();
}

UserServiceImpl.java

package com.xbj.service.impl;

import com.xbj.dao.UserDao;
import com.xbj.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

/** * @Author:晓宇码匠 * @Date：2019/6/15 0015 */
@Service
public class UserServiceImpl implements UserService { 
   
    @Autowired
    private UserDao userDao;
    public void addUser() { 
   
       userDao.addUser();
    }

    public void delUser() { 
   
        userDao.delUser();
    }
}

MyAdvices.java

package com.xbj;

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

/** * @Author:晓宇码匠 * @Date：2019/6/15 0015 */
/* * 注意类的包名 * */

@Component
public class MyAdvices { 
   
        //前置通知
    public void before(JoinPoint joinpoint){ 
   
        System.out.println("前置通知");
    }
        //正常放回通知
    public void afterRunturn(JoinPoint joinpoint){ 
   
        System.out.println("afterRunturn");

    }
        //最终返回通知
    public void afterfinally(JoinPoint joinpoint){ 
   
        System.out.println("afterfinally");
    }
        //环绕通知
    public void around(ProceedingJoinPoint proceedingJoinPoint){ 
   
        System.out.println("around-before");
        try { 
   
            proceedingJoinPoint.proceed();
        } catch (Throwable throwable) { 
   
            throwable.printStackTrace();
        }
        System.out.println("around-after");
    }
        //异常通知
    public void afterThorw(Throwable ex){ 
   
        System.out.println("afterThorw"+ex);

    }
}

test.java

import com.xbj.controller.UserController;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;


/** * @Author:晓宇码匠 * @Date：2019/6/15 0015 */
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = { 
   "classpath:applicationContext.xml"})
public class test { 
   
    @Autowired
    private UserController controller;
    @Test
    public void t1() { 
   
        controller.addUser();
    }
}

控制台输出：

前置通知
around-before
addUser
around-after
afterfinally
afterRunturn