以下内容整理自http://how2j.cn/k/spring/spring-aop/89.html#nowhere和http://how2j.cn/k/spring/spring-annotaion-aop/1068.html#nowhere
1.Spring的AOP特性
AOP 即 Aspect Oriented Program 面向切面编程
首先，在面向切面编程的思想里面，把功能分为核心业务功能，和周边功能。
所谓的核心业务，比如登陆，增加数据，删除数据都叫核心业务
所谓的周边功能，比如性能统计，日志，事务管理等等
周边功能在Spring的面向切面编程AOP思想里，即被定义为切面
在面向切面编程AOP的思想里面，核心业务功能和切面功能分别独立进行开发,然后把切面功能和核心业务功能 “编织” 在一起，这就叫AOP
2.利用xml配置AOP
首先准备业务类ProductService
package com.how2java.service;
public class ProductService {
public void doSomeService(){
System.out.println("doSomeService");
}
}然后准备日志切面LoggerAspect
package com.how2java.aspect;
import org.aspectj.lang.ProceedingJoinPoint;
public class LoggerAspect {
public Object log(ProceedingJoinPoint joinPoint) throws Throwable {
System.out.println("start log:" + joinPoint.getSignature().getName());
Object object = joinPoint.proceed();
System.out.println("end log:" + joinPoint.getSignature().getName());
return object;
}
}然后是配置文件applicationContext.xml
<bean name=”s” class=”com.how2java.service.ProductService”> </bean>
声明业务对象
<bean id=”loggerAspect” class=”com.how2java.aspect.LoggerAspect”/>
声明日志切面
结合
思路图
<aop:pointcut id=”loggerCutpoint” expression= “execution(* com.how2java.service.ProductService.*(..)) “/>
指定右边的核心业务功能
<aop:aspect id=”logAspect” ref=”loggerAspect”> <aop:around pointcut-ref=”loggerCutpoint” method=”log”/> </aop:aspect>
指定左边的辅助功能
然后通过aop:config把业务对象与辅助功能编织在一起。
execution(* com.how2java.service.ProductService.*(..))
这表示对满足如下条件的方法调用，进行切面操作：
*
返回任意类型
com.how2java.service.ProductService.*
包名以 com.how2java.service.ProductService 开头的类的任意方法
(..)
参数是任意数量和类型
<?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"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:context="http://www.springframework.org/schema/context"
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
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd">
<bean name="c" class="com.how2java.pojo.Category">
<property name="name" value="yyy" />
</bean>
<bean name="p" class="com.how2java.pojo.Product">
<property name="name" value="product1" />
<property name="category" ref="c" />
</bean>
<bean name="s" class="com.how2java.service.ProductService">
</bean>
<bean id="loggerAspect" class="com.how2java.aspect.LoggerAspect"/>
<aop:config>
<aop:pointcut id="loggerCutpoint"
expression=
"execution(* com.how2java.service.ProductService.*(..)) "/>
<aop:aspect id="logAspect" ref="loggerAspect">
<aop:around pointcut-ref="loggerCutpoint" method="log"/>
</aop:aspect>
</aop:config>
</beans>运行测试代码
package com.how2java.test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.how2java.service.ProductService;
public class TestSpring {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext(
new String[] { "applicationContext.xml" });
ProductService s = (ProductService) context.getBean("s");
s.doSomeService();
}
}结果如下：
3.AOP基于注解的方式
首先注解配置业务类
使用@Component(“s”) 注解ProductService 类，表示其是一个bean
package com.how2java.service;
import org.springframework.stereotype.Component;
@Component("s")
public class ProductService {
public void doSomeService(){
System.out.println("doSomeService");
}
}然后注解配置切面
@Aspect 注解表示这是一个切面
@Component 表示这是一个bean,由Spring进行管理
@Around(value = “execution(* com.how2java.service.ProductService.*(..))”) 表示对com.how2java.service.ProductService 这个类中的所有方法进行切面操作
package com.how2java.aspect;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.stereotype.Component;
@Aspect
@Component
public class LoggerAspect {
@Around(value = "execution(* com.how2java.service.ProductService.*(..))")
public Object log(ProceedingJoinPoint joinPoint) throws Throwable {
System.out.println("start log:" + joinPoint.getSignature().getName());
Object object = joinPoint.proceed();
System.out.println("end log:" + joinPoint.getSignature().getName());
return object;
}
}然后是配置文件applicationContext.xml
去掉原有信息，添加如下3行
<context:component-scan base-package=”com.how2java.aspect”/> <context:component-scan base-package=”com.how2java.service”/>
扫描包com.how2java.aspect和com.how2java.service，定位业务类和切面类
<aop:aspectj-autoproxy/>
找到被注解了的切面类，进行切面配置
<?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"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:context="http://www.springframework.org/schema/context"
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
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd">
<context:component-scan base-package="com.how2java.aspect"/>
<context:component-scan base-package="com.how2java.service"/>
<aop:aspectj-autoproxy/>
</beans>运行测试代码以后
package com.how2java.test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.how2java.service.ProductService;
public class TestSpring {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext(
new String[] { "applicationContext.xml" });
ProductService s = (ProductService) context.getBean("s");
s.doSomeService();
}
}结果和利用xml配置的一样
