Aop初步了解

AOP(aspect-oriented programming)

一、术语

JoinPoints(织入点) :在应用中可能有很多个机会可以应用通知，这些机会就叫做织入点,织入点可能是正在调用的方法、正在抛出的异常或者是正在被修改的属性。

Advice(通知)：定义在连接点做什么,什么时候做，为切面增强提供接口。

Aspect(切面)：JoinPoints+Advice

PointCuts(切点):切面具体执行的织入点，具体就是切面在何处执行

Weaving(编织):将切面与目标对象(target object)进行连接，可以在编译期、加载期、运行期

二、spring注解实现aop

//被代理类
@Component
public class TargetObject {
public void test(){
System.out.println("target Object is running");
}
}

//切面类
@Component
@Aspect
public class AspectMethod {
@Before("execution(public void demo.aspect.TargetObject.test())")
public void printDateStart(){
System.out.println("startTime:"+new Date(System.currentTimeMillis()));
}
@After("execution(public void demo.aspect.TargetObject.test())")
public void printDateEnd(){
System.out.println("endTime:"+new Date(System.currentTimeMillis()));;
}
}

//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:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="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.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd"> <context:annotation-config />
<context:component-scan base-package="demo.aspect"/>
<aop:aspectj-autoproxy proxy-target-class="true"/>
</beans>

//main运行类
public class Main {
public static void main(String[] args) {
FileSystemXmlApplicationContext ac=new FileSystemXmlApplicationContext("src/main/resource/beans.xml");
TargetObject test=ac.getBean(TargetObject.class);
test.test();
}
}

//结果