AOP的第五种实现方式-xml通知（#千锋#）

1.IUserServcie.java

package com.zy.aop05;

import java.util.List;

public interface IUserService {

/**

* 获取所有的用户对象列表

* @return

List<Object> getAllUser();

/**

* 保存用户

* @param user

* @return

boolean saveUser(Object user);

/**

* 根据用户uid删除该uid对应的用户信息

* @param uid

* @return

boolean deleteUser(int uid);

/**

* 更新指定用户信息

* @param obj

* @return

boolean updateUser(Object obj);

void getUserByUid();

}

2.UserServiceImpl.java

package com.zy.aop05;

import java.util.ArrayList;

import java.util.List;

public class UserServiceImpl implements IUserService {

@Override

public List<Object> getAllUser() {

System.out.println("--------getAllUser----------");

return new ArrayList<>();

}

@Override

public boolean saveUser(Object user) {

System.out.println("--------saveUser----------");

return true;

}

@Override

public boolean deleteUser(int uid) {

System.out.println("--------deleteUser----------");

return false;

}

@Override

public boolean updateUser(Object obj) {

System.out.println("--------updateUser----------");

return true;

}

@Override

public void getUserByUid() {

System.out.println("--------getUserByUid----------");

System.out.println(1 / 0);

String str = null;

System.out.println(str.length());

}

3.MyAspect.java

package com.zy.aop05;

import org.aspectj.lang.JoinPoint;

import org.aspectj.lang.ProceedingJoinPoint;

import java.util.Arrays;

/**

* 五种通知方式来实现aop

* 1. 前置通知，在业务方法之前执行

* 2. 后置通知，在业务方法之后执行

* 3. 环绕通知，同时在业务方法的前后执行

* 4. 带有返回值通知，可以拿到业务方法的返回值

* 5. 异常通知，可以捕获业务方法中的异常对象

* 注意：如果同时配置来所有的通知方式，则执行顺序依次为：

* before>around before>业务方法 >after returning > around after > after

* before>around before>业务方法 >after throwing > after

* ps. 使用注解的话是环绕通知proceed方法之前部分先执行，使用xml配置的话取决于aop:before和aop:around的配置顺序

public class MyAspect {

public void myBefore(JoinPoint jp){

// System.out.println("args " + Arrays.toString(jp.getArgs()));

// System.out.println("toString " + jp.toString());

// System.out.println("getTarget " + jp.getTarget());

System.out.println("this is before.");

}

public void myAfter(JoinPoint jp){

System.out.println("this is after.");

}

public Object myAround(ProceedingJoinPoint pjp){

try {

System.out.println("this is around before");

Object obj = pjp.proceed();

System.out.println("this is around after " + obj);

return obj;

} catch (Throwable throwable) {

throwable.printStackTrace();

}

return null;

}

/**

* 带有返回值的通知

* @param jp

* @param obj 配置文件中的obj

public void myReturn(JoinPoint jp, Object obj){

System.out.println("this is after returning " + obj);

}

public void myThrow(JoinPoint jp, Throwable e){

System.out.println("this is after throwing " + e.getMessage());

}

4.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">

<aop:config proxy-target-class="true">

<aop:aspect ref="ma">

<aop:pointcut id="mpc" expression="execution(* com.zy.aop05.*.*(..))" />

<aop:before method="myBefore" pointcut-ref="mpc"/>

<aop:after method="myAfter" pointcut-ref="mpc" />

<aop:around method="myAround" pointcut-ref="mpc" />

<aop:after-returning method="myReturn" pointcut-ref="mpc" returning="obj" />

<aop:after-throwing method="myThrow" pointcut-ref="mpc" throwing="e" />

</aop:aspect>

</aop:config>

</beans>

5.TestAOP05.java

package com.zy.aop05;

import org.junit.Test;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestAOP05 {

@Test

public void test(){

ApplicationContext ac = new ClassPathXmlApplicationContext("com/zy/aop05/beans.xml");

IUserService us = ac.getBean("us", IUserService.class);

us.updateUser(new Object());

us.getAllUser();

us.saveUser(new Object());

us.deleteUser(1);

us.getUserByUid();

}