此前对于AOP的使用仅限于声明式事务,除此之外在实际开发中也没有遇到过与之相关的问题。最近项目中遇到了以下几点需求,仔细思考之后,觉得采用AOP 来解决。一方面是为了以更加灵活的方式来解决问题,另一方面是借此机会深入学习Spring AOP相关的内容。本文是权当本人的自己AOP学习笔记,以下需求不用AOP肯定也能解决,至于是否牵强附会,仁者见仁智者见智。
- 对部分函数的调用进行日志记录,用于观察特定问题在运行过程中的函数调用情况
- 监控部分重要函数,若抛出指定的异常,需要以短信或邮件方式通知相关人员
- 金控部分重要函数的执行时间
事实上,以上需求没有AOP也能搞定,只是在实现过程中比较郁闷摆了。
- 需要打印日志的函数分散在各个包中,只能找到所有的函数体,手动添加日志。然而这些日志都是临时的,待问题解决之后应该需要清除打印日志的代码,只能再次手动清除^_^!
- 类 似1的情况,需要捕获异常的地方太多,如果手动添加时想到很可能明天又要手动清除,只能再汗。OK,该需求相对比较固定,属于长期监控的范畴,并不需求临 时添加后再清除。然而,客户某天要求,把其中20%的异常改为短信提醒,剩下的80%改用邮件提醒。改之,两天后,客户抱怨短信太多,全部改成邮件提 醒...
- 该需求通常用于监控某些函数的执行时间,用以判断系统执行慢的瓶颈所在。瓶颈被解决之后,烦恼同情况1
终于下定决心,采用AOP来解决!代码如下:
切面类TestAspect
- package com.spring.aop;
- /**
- * 切面
- *
- */
- public class TestAspect {
- public void doAfter(JoinPoint jp) {
- System.out.println("log Ending method: "
- + jp.getTarget().getClass().getName() + "."
- + jp.getSignature().getName());
- }
- public Object doAround(ProceedingJoinPoint pjp) throws Throwable {
- long time = System.currentTimeMillis();
- Object retVal = pjp.proceed();
- time = System.currentTimeMillis() - time;
- System.out.println("process time: " + time + " ms");
- return retVal;
- }
- public void doBefore(JoinPoint jp) {
- System.out.println("log Begining method: "
- + jp.getTarget().getClass().getName() + "."
- + jp.getSignature().getName());
- }
- public void doThrowing(JoinPoint jp, Throwable ex) {
- System.out.println("method " + jp.getTarget().getClass().getName()
- + "." + jp.getSignature().getName() + " throw exception");
- System.out.println(ex.getMessage());
- }
- private void sendEx(String ex) {
- //TODO 发送短信或邮件提醒
- }
- }
- package com.spring.service;
- /**
- * 接口A
- */
- public interface AService {
- public void fooA(String _msg);
- public void barA();
- }
- package com.spring.service;
- /**
- *接口A的实现类
- */
- public class AServiceImpl implements AService {
- public void barA() {
- System.out.println("AServiceImpl.barA()");
- }
- public void fooA(String _msg) {
- System.out.println("AServiceImpl.fooA(msg:"+_msg+")");
- }
- }
- package com.spring.service;
- /**
- * Service类B
- */
- public class BServiceImpl {
- public void barB(String _msg, int _type) {
- System.out.println("BServiceImpl.barB(msg:"+_msg+" type:"+_type+")");
- if(_type == 1)
- throw new IllegalArgumentException("测试异常");
- }
- public void fooB() {
- System.out.println("BServiceImpl.fooB()");
- }
- }
ApplicationContext
- <?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-2.0.xsd
- http://www.springframework.org/schema/aop
- http://www.springframework.org/schema/aop/spring-aop-2.5.xsd"
- default-autowire="autodetect">
- <aop:config>
- <aop:aspect id="TestAspect" ref="aspectBean">
- <!--配置com.spring.service包下所有类或接口的所有方法-->
- <aop:pointcut id="businessService"
- expression="execution(* com.spring.service.*.*(..))" />
- <aop:before pointcut-ref="businessService" method="doBefore"/>
- <aop:after pointcut-ref="businessService" method="doAfter"/>
- <aop:around pointcut-ref="businessService" method="doAround"/>
- <aop:after-throwing pointcut-ref="businessService" method="doThrowing" throwing="ex"/>
- </aop:aspect>
- </aop:config>
- <bean id="aspectBean" class="com.spring.aop.TestAspect" />
- <bean id="aService" class="com.spring.service.AServiceImpl"></bean>
- <bean id="bService" class="com.spring.service.BServiceImpl"></bean>
- </beans>
测试类AOPTest
- public class AOPTest extends AbstractDependencyInjectionSpringContextTests {
- private AService aService;
- private BServiceImpl bService;
- protected String[] getConfigLocations() {
- String[] configs = new String[] { "/applicationContext.xml"};
- return configs;
- }
- /**
- * 测试正常调用
- */
- public void testCall()
- {
- System.out.println("SpringTest JUnit test");
- aService.fooA("JUnit test fooA");
- aService.barA();
- bService.fooB();
- bService.barB("JUnit test barB",0);
- }
- /**
- * 测试After-Throwing
- */
- public void testThrow()
- {
- try {
- bService.barB("JUnit call barB",1);
- } catch (IllegalArgumentException e) {
- }
- }
- public void setAService(AService service) {
- aService = service;
- }
- public void setBService(BServiceImpl service) {
- bService = service;
- }
- }
运行结果如下:
- log Begining method: com.spring.service.AServiceImpl.fooA
- AServiceImpl.fooA(msg:JUnit test fooA)
- log Ending method: com.spring.service.AServiceImpl.fooA
- process time: 0 ms
- log Begining method: com.spring.service.AServiceImpl.barA
- AServiceImpl.barA()
- log Ending method: com.spring.service.AServiceImpl.barA
- process time: 0 ms
- log Begining method: com.spring.service.BServiceImpl.fooB
- BServiceImpl.fooB()
- log Ending method: com.spring.service.BServiceImpl.fooB
- process time: 0 ms