Spring AOP 前置、后置、返回后、异常通知

 

package com.spring.aoc.dao;

public class UserDao {
    public void insert(){
        System.out.println("新增用户数据");
    }
}

package com.spring.aoc.service;

import com.spring.aoc.dao.UserDao;

public class UserService {
    private UserDao userDao;

    public void createUser(){
//        if(1==1){
//            throw new RuntimeException("用户已存在");
//        }
        System.out.println("执行创建用户业务逻辑");
        userDao.insert();
    }

    public String generateRandomPassword(String type , Integer length){
        System.out.println("按" + type + "方式生成" + length + "位随机密码");
        return "JIUjKJ51";
    }

    public UserDao getUserDao() {
        return userDao;
    }

    public void setUserDao(UserDao userDao) {
        this.userDao = userDao;
    }
}

package com.spring.aoc.aspect;

import org.aspectj.lang.JoinPoint;

import java.text.SimpleDateFormat;
import java.util.Date;

//切面类
public class MethodAspect {
    //切面方法，用于扩展额外的功能，JoinPoint 连接点
    //通过连接点可以获取目标类/目标方法的信息
    //前置通知
    public void printExecutionTime(JoinPoint joinPoint){
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss SSS");
        String now = sdf.format(new Date());
        String className = joinPoint.getTarget().getClass().getName();//获取目标类的名称
        String methodName = joinPoint.getSignature().getName();//获取目标方法的名称
        System.out.println("触发前置通知---->" + now + ":" + className + "." + methodName);
        Object[] args = joinPoint.getArgs();
        System.out.println("---->参数个数:"+args.length);
        for(Object arg : args){
            System.out.println("---->参数:"+arg);
        }
    }
    //返回后通知
    public void doAfterReturning(JoinPoint joinPoint,Object ret){
        System.out.println("<----返回后通知："+ret);
    }
    //异常通知
    public void doAfterThrowing(JoinPoint joinPoint,Throwable th){
        System.out.println("<----异常通知：" + th.getMessage());
    }
    //后置通知
    public void doAfter(JoinPoint joinPoint){
        System.out.println("<----触发后置通知");
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<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"
       xmlns="http://www.springframework.org/schema/beans"
       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">
    <bean id="userDao" class="com.spring.aoc.dao.UserDao"/>
    <bean id="employeeDao" class="com.spring.aoc.dao.EmployeeDao"/>
    <bean id="userService" class="com.spring.aoc.service.UserService">
        <property name="userDao" ref="userDao"/>
    </bean>
    <bean id="employeeService" class="com.spring.aoc.service.EmployeeService">
        <property name="employeeDao" ref="employeeDao"/>
    </bean>
    <!--AOP配置-->
    <bean id="methodAspect" class="com.spring.aoc.aspect.MethodAspect"></bean>
    <aop:config>
        <!--pointcut 切点，使用execution表达式描述切面的作用范围-->
        <!--execution(public * com.spring..*.*(..)) 说明切面作用在com.spring包下的所有类的所有方法-->
        <aop:pointcut id="pointcut" expression="execution(public * com.spring..*Service.*(..))"/>
        <!--定义切面类-->
        <aop:aspect ref="methodAspect">
            <!--before通知，代表在目标方法运行前先执行methodAspect.printExecutionTime()-->
            <aop:before method="printExecutionTime" pointcut-ref="pointcut"/>
            <!--after、after-returning、after-throwing 按书写顺序打印-->
            <aop:after method="doAfter" pointcut-ref="pointcut"/>
            <aop:after-returning method="doAfterReturning" returning="ret" pointcut-ref="pointcut"/>
            <aop:after-throwing method="doAfterThrowing" throwing="th" pointcut-ref="pointcut"/>
        </aop:aspect>
    </aop:config>
</beans>

package com.spring.aoc;

import com.spring.aoc.service.UserService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class SpringApplication {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("classpath:applicationContext.xml");
        UserService userService = context.getBean("userService", UserService.class);
        userService.createUser();
        userService.generateRandomPassword("MD5",16);
    }
}