Spring 切面 AOP基础 之四

Spring AOP在企业应用中 通常与AspectJ结合使用，尤其是在注解AOP的时候。

话不多说，talk is cheap,i'll show you code。

引用Pom.xml 加入AspectJ的依赖

<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/maven-v4_0_0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com.mkyong.core</groupId><artifactId>Spring3Example</artifactId><packaging>jar</packaging><version>1.0-SNAPSHOT</version><name>Spring3Example</name><url>http://maven.apache.org</url><properties><spring.version>3.0.5.RELEASE</spring.version></properties><dependencies><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.8.2</version><scope>test</scope></dependency><!-- Spring 3 dependencies --><dependency><groupId>org.springframework</groupId><artifactId>spring-core</artifactId><version>${spring.version}</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>${spring.version}</version></dependency><!-- Spring AOP + AspectJ --><dependency><groupId>org.springframework</groupId><artifactId>spring-aop</artifactId><version>${spring.version}</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><!-- JavaConfig need this library --><dependency><groupId>cglib</groupId><artifactId>cglib</artifactId><version>2.2.2</version></dependency></dependencies></project>

2、写service类

接口 Customerbo.java

public interface CustomerBo {void addCustomer();String addCustomerReturnValue();void addCustomerThrowException() throws Exception;void addCustomerAround(String name);}

实现类CustomerboImpl.java

public class CustomerBoImpl implements CustomerBo {public void addCustomer(){System.out.println("addCustomer() is running ");}public String addCustomerReturnValue(){System.out.println("addCustomerReturnValue() is running ");return "abc";}public void addCustomerThrowException() throws Exception {System.out.println("addCustomerThrowException() is running ");throw new Exception("Generic Error");}public void addCustomerAround(String name){System.out.println("addCustomerAround() is running, args : " + name);}}

3、要注解的切面类

LoggingAspect.java

import java.util.Arrays;import org.aspectj.lang.JoinPoint;import org.aspectj.lang.ProceedingJoinPoint;import org.aspectj.lang.annotation.After;import org.aspectj.lang.annotation.AfterReturning;import org.aspectj.lang.annotation.AfterThrowing;import org.aspectj.lang.annotation.Around;import org.aspectj.lang.annotation.Aspect;import org.aspectj.lang.annotation.Before;@Aspectpublic class LoggingAspect {/*@Before("execution(* CustomerBo.addCustomer(..))")public void logBefore(JoinPoint joinPoint) {System.out.println("logBefore() is running!");System.out.println("hijacked : " + joinPoint.getSignature().getName());System.out.println("******");}*//*@After("execution(* CustomerBo.addCustomer(..))")public void logAfter(JoinPoint joinPoint) {System.out.println("logAfter() is running!");System.out.println("hijacked : " + joinPoint.getSignature().getName());System.out.println("******");}*//*@AfterReturning(pointcut = "execution(* CustomerBo.addCustomerReturnValue(..))",returning= "result")public void logAfterReturning(JoinPoint joinPoint, Object result) {System.out.println("logAfterReturning() is running!");System.out.println("hijacked : " + joinPoint.getSignature().getName());System.out.println("Method returned value is : " + result);System.out.println("******");}*//*@AfterThrowing(pointcut = "execution(* CustomerBo.addCustomerThrowException(..))",throwing= "error")public void logAfterThrowing(JoinPoint joinPoint, Throwable error) {System.out.println("logAfterThrowing() is running!");System.out.println("hijacked : " + joinPoint.getSignature().getName());System.out.println("Exception : " + error);System.out.println("******");}*/@Around("execution(* CustomerBo.addCustomerAround(..))")public void logAround(ProceedingJoinPoint joinPoint) throws Throwable {System.out.println("logAround() is running!");System.out.println("hijacked method : " + joinPoint.getSignature().getName());System.out.println("hijacked arguments : " + Arrays.toString(joinPoint.getArgs()));System.out.println("Around before is running!");Object proceed = joinPoint.proceed();System.out.println("Around after is running!");System.out.println("******");}}

3、配置spring文件，让注解绑定

Spring-Customer.java

<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/beanshttp://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd "><aop:aspectj-autoproxy /><bean id="customerBo" class="CustomerBoImpl" /><!-- Aspect --><bean id="logAspect" class="LoggingAspect" /></beans>

4、执行测试，查看效果

import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;import com.mkyong.customer.bo.CustomerBo;public class App {public static void main(String[] args) throws Exception {ApplicationContext appContext = new ClassPathXmlApplicationContext("Spring-Customer.xml");CustomerBo customer = (CustomerBo) appContext.getBean("customerBo");//customer.addCustomer();//customer.addCustomerReturnValue();//customer.addCustomerThrowException();customer.addCustomerAround("mkyong");}}

结果：我们看到addCustomerAround执行了切面的内容，达到了目的。

注解类型如上四种 

附：如果不用注解在LoggingAspect上，也可以在xml文件配置AOP切面。去掉@Aspect等之后，作如下配置

Spring-Customer.xml

<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/beanshttp://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd "><aop:aspectj-autoproxy /><bean id="customerBo" class="CustomerBoImpl" /><!-- Aspect --><bean id="logAspect" class="LoggingAspect" /><aop:config><aop:aspect id="aspectLoggging" ref="logAspect" ><!-- @Before --><aop:pointcut id="pointCutBefore"expression="execution(* CustomerBo.addCustomer(..))" /><aop:before method="logBefore" pointcut-ref="pointCutBefore" /><!-- @After --><aop:pointcut id="pointCutAfter"expression="execution(* CustomerBo.addCustomer(..))" /><aop:after method="logAfter" pointcut-ref="pointCutAfter" /><!-- @AfterReturning --><aop:pointcut id="pointCutAfterReturning"expression="execution(* CustomerBo.addCustomerReturnValue(..))" /><aop:after-returning method="logAfterReturning" returning="result" pointcut-ref="pointCutAfterReturning" /><!-- @AfterThrowing --><aop:pointcut id="pointCutAfterThrowing"expression="execution(* CustomerBo.addCustomerThrowException(..))" /><aop:after-throwing method="logAfterThrowing" throwing="error" pointcut-ref="pointCutAfterThrowing"  /><!-- @Around --><aop:pointcut id="pointCutAround"expression="execution(* CustomerBo.addCustomerAround(..))" /><aop:around method="logAround" pointcut-ref="pointCutAround"  /></aop:aspect></aop:config></beans>