一、AOP简介：
二、AOP实例：
三、使用的例子
需求：在student添加的前后，打印日志信息；
0）spring AOP需要引用的jar包：
1）StudentService.java接口：
package com.cy.service;
public interface StudentService {
public void addStudent(String name);
}
2）StudentServiceImpl.java实现类：
package com.cy.service.impl;
import com.cy.service.StudentService;
public class StudentServiceImpl implements StudentService {
@Override
public void addStudent(String name) {
System.out.println("添加学生"+name);
}
}
3）StudentServiceAspect.java切面类：
package com.cy.advice; import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint; public class StudentServiceAspect { //前置通知，方法执行之前
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 方法完成之后
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("完成添加学生：" + jp.getArgs()[0]);
} //环绕通知 可以在业务方法的前后添加逻辑
public Object doAround(ProceedingJoinPoint pjp) throws Throwable{
System.out.println("添加学生前");
Object retVal = pjp.proceed(); //retVal为StudentServiceImpl.addStudent(String name)方法的返回值
//因为返回值为void，所以console打印null
System.out.println("添加学生后");
System.out.println(retVal);
return retVal;
} //返回通知
public void doAfterReturning(JoinPoint jp){
System.out.println("返回通知");
} //异常通知
public void doAfterThrowing(JoinPoint jp, Throwable ex){
System.out.println("异常通知");
System.out.println("异常信息：" + ex.getMessage());
}
}
4）beans.xml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"
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-2.5.xsd"> <bean id="studentService" class="com.cy.service.impl.StudentServiceImpl"></bean>
<bean id="studentServiceAspect" class="com.cy.advice.StudentServiceAspect"></bean> <aop:config>
<aop:aspect id="studentServiceAspect" ref="studentServiceAspect">
<aop:pointcut expression="execution(* com.cy.service..*.*(..))" id="businessService"/>
<aop:before method="doBefore" pointcut-ref="businessService"/>
<aop:after method="doAfter" pointcut-ref="businessService"/>
<aop:around method="doAround" pointcut-ref="businessService"/>
<aop:after-returning method="doAfterReturning" pointcut-ref="businessService"/>
<aop:after-throwing method="doAfterThrowing" pointcut-ref="businessService" throwing="ex"/>
</aop:aspect>
</aop:config> </beans>
5）测试代码：
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");
}
}
1）没有异常抛出时，没有异常通知；console打印：
2）addStudent方法中构造异常，有异常通知，console打印：
StudentServiceImpl.java:
package com.cy.service.impl;
import com.cy.service.StudentService;
public class StudentServiceImpl implements StudentService {
@Override
public void addStudent(String name) {
System.out.println("添加学生"+name);
System.out.println(1/0);
}
}
doAround方法中抛出异常是这句话：
-- Object retVal = pjp.proceed();