AOP和IOC一样都是Spring中的核心思想
AOP 简介:面向切面编程(也叫面向方面编程):Aspect Oriented Programming(AOP),是软件开发中的一个热点,也是 Spring 框架中的一个重要内容。利用 AOP 可以对业务逻辑的各个部分进行隔离,从而使得业务逻辑各部分之间的耦合度降低,提高程序的可重用性,同时提高了开发的效率。
主要的功能有:日志记录,性能统计,安全控制,事务处理,异常处理。
下面来一个实例演示:
总体目录:
对应的jar包(注意,这里要导入aop对应的三个包):
StudentServiceAspect.java:
package com.java1234.advice;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
public class StudentServiceAspect {
//AOP切面,前置通知。都引入JointPoint参数
public void doBefore(JoinPoint jp){
System.out.println("类名:"+jp.getTarget().getClass().getName());
System.out.println("方法名:"+jp.getSignature().getName());
System.out.println("开始添加学生:"+jp.getArgs()[0]);
}
//后置通知
public void doAfter(JoinPoint jp){
System.out.println("类名:"+jp.getTarget().getClass().getName());
System.out.println("方法名:"+jp.getSignature().getName());
System.out.println("开始添加学生:"+jp.getArgs()[0]);
}
//环绕通知
public Object doAround(ProceedingJoinPoint pjp) throws Throwable{
System.out.println("添加学生前");
Object retVal=pjp.proceed();
System.out.println(retVal);
System.out.println("添加学生后");
return retVal;
}
}
StudentService.java:
package com.java1234.service;
public interface StudentService {
public void addStudent(String name);
}
StudentServiceImpl.java:
package com.java1234.service.impl;
import com.java1234.service.StudentService;
public class StudentServiceImpl implements StudentService{
@Override
public void addStudent(String name) {
System.out.println("添加学生"+name);
}
}
T.java:
package com.java1234.test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.java1234.service.StudentService;
public class T {
public static void main(String[] args) {
ApplicationContext ac=new ClassPathXmlApplicationContext("beans.xml");
StudentService studentService=(StudentService)ac.getBean("studentService");
studentService.addStudent("张三");
}
}
beans.xml:
<?xml version="1.0" encoding="UTF-8"?>
<!-- 添加AOP对应的命名空间,这里在Spring文档中有 -->
<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.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd">
<!-- 定义切面 -->
<bean id="studentServiceAspect" class="com.java1234.advice.StudentServiceAspect"></bean>
<bean id="studentService" class="com.java1234.service.impl.StudentServiceImpl"></bean>
<!-- aop配置 -->
<aop:config>
<aop:aspect id="studentServiceAspect" ref="studentServiceAspect">
<!-- 定义切点 -->
<aop:pointcut expression="execution(* com.java1234.service.*.*(..))" id="businessService"/>
<aop:before method="doBefore" pointcut-ref="businessService"/>
<aop:after method="doAfter" pointcut-ref="businessService"/>
<aop:after method="doAfter" pointcut-ref="businessService"/>
<aop:around method="doAround" pointcut-ref="businessService"/>
</aop:aspect>
</aop:config>
</beans>
注意:AOP对应的通知有前置通知,后置通知,环绕通知,返回通知,异常通知这五种,这里只演示前面三种,前三种比较常用。最后两种大家可以自行演示哦。
//测试结果: