aop面向切面编程,拦截指定函数,在调用前,后作一些其他操作
<dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>4.1.4.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context-support</artifactId> <version>4.1.4.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aop</artifactId> <version>4.1.4.RELEASE</version> </dependency> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjrt</artifactId> <version>1.6.11</version> </dependency> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjweaver</artifactId> <version>1.6.11</version> </dependency>
package aop.annotation; public class HelloWorld { public void sayHello() { System.out.println("hello world"); } }
package aop.annotation; import org.aspectj.lang.JoinPoint; import org.aspectj.lang.annotation.After; import org.aspectj.lang.annotation.Aspect; import org.aspectj.lang.annotation.Before; import org.aspectj.lang.annotation.Pointcut; import org.springframework.beans.factory.BeanFactory; import org.springframework.context.support.ClassPathXmlApplicationContext; import org.springframework.stereotype.Component; @Component @Aspect public class Annotation { // 定义拦截函数,aspect函数的作用域相当于一个id @Pointcut("execution(* aop.annotation.HelloWorld.sayHello(..))") public void aspectBefore(){ } @Pointcut("execution(* aop.annotation.HelloWorld.sayHello(..))") public void aspectAfter(){ } /** * aspectBefore函数对应的函数被拦截前执行,doBefore函数 */ @Before("aspectBefore()") private void doBefore(JoinPoint joinPoint) { System.out.println("-----doBefore().invoke-----"); } /** * aspectAfter函数对应的函数被拦截前执行,doBefore函数 */ @After("aspectAfter()") private void doAfter(JoinPoint joinPoint) { System.out.println("-----doAfter().invoke-----"); } }
public static void main(String[] args) { BeanFactory factory = new ClassPathXmlApplicationContext("spring_aop_annotation.xml"); HelloWorld userManager = (HelloWorld)factory.getBean("helloWorld"); userManager.sayHello(); }
<?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 http://www.springframework.org/schema/aop/spring-aop-3.1.xsd 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-3.0.xsd"> <!-- 激活组件扫描功能,在包cn.ysh.studio.spring.aop及其子包下面自动扫描通过注解配置的组件 --> <context:component-scan base-package="aop.annotation"/> <!-- 激活自动代理功能 --> <aop:aspectj-autoproxy proxy-target-class="true"/> <bean id="helloWorld" class="aop.annotation.HelloWorld"/> </beans>
package aop.xml; public class UserManagerImpl { public String findUserById(int userId) { System.out.println("---------HelloWorld.sayHello()--------"); if (userId <= 0) { throw new IllegalArgumentException("该用户不存在!"); } return "张三"; } }
package aop.xml; import org.aspectj.lang.JoinPoint; import org.aspectj.lang.ProceedingJoinPoint; import org.springframework.beans.factory.BeanFactory; import org.springframework.context.support.ClassPathXmlApplicationContext; /** * Advice通知类 * 测试after,before,around,throwing,returning Advice. * @author Admin * */ public class XMLAdvice { /** * 在核心业务执行前执行,不能阻止核心业务的调用。 * @param joinPoint */ private void doBefore(JoinPoint joinPoint) { System.out.println("-----doBefore().invoke-----"); System.out.println(" 此处意在执行核心业务逻辑前,做一些安全性的判断等等"); System.out.println(" 可通过joinPoint来获取所需要的内容"); System.out.println("-----End of doBefore()------"); } /** * 手动控制调用核心业务逻辑,以及调用前和调用后的处理, * * 注意:当核心业务抛异常后,立即退出,转向After Advice * 执行完毕After Advice,再转到Throwing Advice * @param pjp * @return * @throws Throwable */ private Object doAround(ProceedingJoinPoint pjp) throws Throwable { System.out.println("-----doAround().invoke-----"); System.out.println(" 此处可以做类似于Before Advice的事情"); //调用核心逻辑 Object retVal = pjp.proceed(); System.out.println(" 此处可以做类似于After Advice的事情"); System.out.println("-----End of doAround()------"); return retVal; } /** * 核心业务逻辑退出后(包括正常执行结束和异常退出),执行此Advice * @param joinPoint */ private void doAfter(JoinPoint joinPoint) { System.out.println("-----doAfter().invoke-----"); System.out.println(" 此处意在执行核心业务逻辑之后,做一些日志记录操作等等"); System.out.println(" 可通过joinPoint来获取所需要的内容"); System.out.println("-----End of doAfter()------"); } /** * 核心业务逻辑调用正常退出后,不管是否有返回值,正常退出后,均执行此Advice * @param joinPoint */ private void doReturn(JoinPoint joinPoint) { System.out.println("-----doReturn().invoke-----"); System.out.println(" 此处可以对返回值做进一步处理"); System.out.println(" 可通过joinPoint来获取所需要的内容"); System.out.println("-----End of doReturn()------"); } /** * 核心业务逻辑调用异常退出后,执行此Advice,处理错误信息 * @param joinPoint * @param ex */ private void doThrowing(JoinPoint joinPoint,Throwable ex) { System.out.println("-----doThrowing().invoke-----"); System.out.println(" 错误信息:"+ex.getMessage()); System.out.println(" 此处意在执行核心业务逻辑出错时,捕获异常,并可做一些日志记录操作等等"); System.out.println(" 可通过joinPoint来获取所需要的内容"); System.out.println("-----End of doThrowing()------"); } }
public static void main(String[] args) { BeanFactory factory = new ClassPathXmlApplicationContext("spring_aop_xml.xml"); UserManagerImpl userManager = (UserManagerImpl)factory.getBean("userManager"); //可以查找张三 userManager.findUserById(1); System.out.println("=====我==是==分==割==线====="); try { // 查不到数据,会抛异常,异常会被AfterThrowingAdvice捕获 userManager.findUserById(0); } catch (IllegalArgumentException e) { } }
<?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-3.0.xsd">--> <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-2.0.xsd"> <bean id="userManager" class="aop.xml.UserManagerImpl"/> <bean id="xmlHandler" class="aop.xml.XMLAdvice" /> <aop:config> <!-- 切面: 拦截某个pointcut后要执行的函数 --> <aop:aspect id="aspect" ref="xmlHandler"> <!-- 切入点: 拦截某个函数 --> <aop:pointcut id="pointUserMgr" expression="execution(* aop.xml.UserManagerImpl.findUserById(..))"/> <!-- 拦截某个函数后(执行函数之前):执行切面(aspect)中的doBefore函数--> <!--<aop:before method="doBefore" pointcut-ref="pointUserMgr"/>--> <!-- 拦截某个函数后(执行函数之后):执行切面(aspect)中的doAfter函数--> <aop:after method="doAfter" pointcut-ref="pointUserMgr"/> <aop:around method="doAround" pointcut-ref="pointUserMgr"/> <aop:after-returning method="doReturn" pointcut-ref="pointUserMgr"/> <aop:after-throwing method="doThrowing" throwing="ex" pointcut-ref="pointUserMgr"/> </aop:aspect> </aop:config> </beans>