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;

@Aspect
public 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/beans http://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/beans http://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>