（三）Spring 之AOP 详解

第一节：AOP 简介

AOP 简介：百度百科；

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。

主要的功能是：日志记录，性能统计，安全控制，事务处理，异常处理等等。

--------

这里我先开头讲一个例子代码程序：

T.java：

package com.wishwzp.test;

import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.wishwzp.service.StudentService;

public class T {

private ApplicationContext ac;

@Before
public void setUp() throws Exception {
ac=new ClassPathXmlApplicationContext("beans.xml");
}

@Test
public void test1() {
StudentService studentService=(StudentService)ac.getBean("studentService");
studentService.addStudent("张三");
}

}

beans.xml:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"> 
<bean id="studentService" class="com.wishwzp.service.impl.StudentServiceImpl"></bean>

</beans>

StudentServiceImpl.java:

package com.wishwzp.service.impl;

import com.wishwzp.service.StudentService;

public class StudentServiceImpl implements StudentService{

@Override
public void addStudent(String name) {
System.out.println("开始添加学生"+name);
System.out.println("添加学生"+name);
System.out.println("完成学生"+name+"的添加");
}

}

StudentService.java:

package com.wishwzp.service;

public interface StudentService {

public void addStudent(String name);
}

运行结果显示：

开始添加学生张三
添加学生张三
完成学生张三的添加

--------------

第二节：Spring AOP 实例

1，前置通知；

2，后置通知；

3，环绕通知；

4，返回通知；

5，异常通知；

1，前置通知；

T.java:

package com.wishwzp.test;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.wishwzp.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"?>
<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"> 
<!-- 注入bean，StudentServiceAspect -->
<bean id="studentServiceAspect" class="com.wishwzp.advice.StudentServiceAspect"></bean>

<!-- 注入bean，StudentServiceImpl -->
<bean id="studentService" class="com.wishwzp.service.impl.StudentServiceImpl"></bean>

<!-- 配置AOP -->
<aop:config>
<aop:aspect id="studentServiceAspect" ref="studentServiceAspect">
<aop:pointcut expression="execution(* com.wishwzp.service.*.*(..))" id="businessService"/>
<aop:before method="doBefore" pointcut-ref="businessService"/>
</aop:aspect>
</aop:config>
</beans>

StudentServiceAspect.java:

package com.wishwzp.advice;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;

public class StudentServiceAspect {

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]);
}

}

StudentServiceImpl.java:

package com.wishwzp.service.impl;

import com.wishwzp.service.StudentService;

public class StudentServiceImpl implements StudentService{

@Override
public void addStudent(String name) {
// System.out.println("开始添加学生"+name);
System.out.println("添加学生"+name);
// System.out.println("完成学生"+name+"的添加");
}

}

StudentService.java:

package com.wishwzp.service;

public interface StudentService {

public void addStudent(String name);
}

运行结果显示：

类名:com.wishwzp.service.impl.StudentServiceImpl
方法名：addStudent
开始添加学生：张三
添加学生张三

2，后置通知；

T.java:

package com.wishwzp.test;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.wishwzp.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"?>
<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"> 
<!-- 注入bean，StudentServiceAspect -->
<bean id="studentServiceAspect" class="com.wishwzp.advice.StudentServiceAspect"></bean>

<!-- 注入bean，StudentServiceImpl -->
<bean id="studentService" class="com.wishwzp.service.impl.StudentServiceImpl"></bean>

<!-- 配置AOP -->
<aop:config>
<aop:aspect id="studentServiceAspect" ref="studentServiceAspect">
<!-- 配置执行切点路径和id -->
<aop:pointcut expression="execution(* com.wishwzp.service.*.*(..))" id="businessService"/>
<!-- 前置通知 -->
<aop:before method="doBefore" pointcut-ref="businessService"/>
<!-- 后置通知 -->
<aop:after method="doAfter" pointcut-ref="businessService"/>
</aop:aspect>
</aop:config>
</beans>

StudentServiceAspect.java:

package com.wishwzp.advice;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;

public class StudentServiceAspect {

//前置通知
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("学生添加完成："+jp.getArgs()[0]);
}
}

StudentServiceImpl.java:

package com.wishwzp.service.impl;

import com.wishwzp.service.StudentService;

public class StudentServiceImpl implements StudentService{

@Override
public void addStudent(String name) {
// System.out.println("开始添加学生"+name);
System.out.println("添加学生"+name);
// System.out.println("完成学生"+name+"的添加");
}

}

StudentService.java:

package com.wishwzp.service;

public interface StudentService {

public void addStudent(String name);
}

运行结果显示：

类名:com.wishwzp.service.impl.StudentServiceImpl
方法名：addStudent
开始添加学生：张三
添加学生张三
类名:com.wishwzp.service.impl.StudentServiceImpl
方法名：addStudent
学生添加完成：张三

3，环绕通知；

T.java:

package com.wishwzp.test;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.wishwzp.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"?>
<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"> 
<!-- 注入bean，StudentServiceAspect -->
<bean id="studentServiceAspect" class="com.wishwzp.advice.StudentServiceAspect"></bean>

<!-- 注入bean，StudentServiceImpl -->
<bean id="studentService" class="com.wishwzp.service.impl.StudentServiceImpl"></bean>

<!-- 配置AOP -->
<aop:config>
<aop:aspect id="studentServiceAspect" ref="studentServiceAspect">
<!-- 配置执行切点路径和id -->
<aop:pointcut expression="execution(* com.wishwzp.service.*.*(..))" id="businessService"/>
<!-- 前置通知 -->
<aop:before method="doBefore" pointcut-ref="businessService"/>
<!-- 后置通知 -->
<aop:after method="doAfter" pointcut-ref="businessService"/>
<!-- 环绕通知 -->
<aop:around method="doAround" pointcut-ref="businessService"/>
</aop:aspect>
</aop:config>
</beans>

StudentServiceAspect.java:

package com.wishwzp.advice;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;

public class StudentServiceAspect {

//前置通知
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("学生添加完成："+jp.getArgs()[0]);
}

//环绕通知,这里添加了返回值
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;
}
}

StudentServiceImpl.java:

package com.wishwzp.service.impl;

import com.wishwzp.service.StudentService;

public class StudentServiceImpl implements StudentService{

@Override
public String addStudent(String name) {
// System.out.println("开始添加学生"+name);
System.out.println("添加学生"+name);
// System.out.println("完成学生"+name+"的添加");
return name;
}

}

StudentService.java:

package com.wishwzp.service;

public interface StudentService {

public String addStudent(String name);
}

运行结果显示：

类名:com.wishwzp.service.impl.StudentServiceImpl
方法名：addStudent
开始添加学生：张三
添加学生前
添加学生张三
张三
添加学生后
类名:com.wishwzp.service.impl.StudentServiceImpl
方法名：addStudent
学生添加完成：张三

4，返回通知；

T.java:

package com.wishwzp.test;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.wishwzp.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"?>
<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"> 
<!-- 注入bean，StudentServiceAspect -->
<bean id="studentServiceAspect" class="com.wishwzp.advice.StudentServiceAspect"></bean>

<!-- 注入bean，StudentServiceImpl -->
<bean id="studentService" class="com.wishwzp.service.impl.StudentServiceImpl"></bean>

<!-- 配置AOP -->
<aop:config>
<aop:aspect id="studentServiceAspect" ref="studentServiceAspect">
<!-- 配置执行切点路径和id -->
<aop:pointcut expression="execution(* com.wishwzp.service.*.*(..))" id="businessService"/>
<!-- 前置通知 -->
<aop:before method="doBefore" pointcut-ref="businessService"/>
<!-- 后置通知 -->
<aop:after method="doAfter" pointcut-ref="businessService"/>
<!-- 环绕通知 -->
<aop:around method="doAround" pointcut-ref="businessService"/>
<!-- 返回通知 -->
<aop:after-returning method="doAfterReturning" pointcut-ref="businessService"/>
</aop:aspect>
</aop:config>
</beans>

StudentServiceAspect.java:

package com.wishwzp.advice;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;

public class StudentServiceAspect {

//前置通知
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("学生添加完成："+jp.getArgs()[0]);
}

//环绕通知,这里添加了返回值
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;
}

//返回通知
public void doAfterReturning(JoinPoint jp){
System.out.println("返回通知");
}
}

StudentServiceImpl.java:

package com.wishwzp.service.impl;

import com.wishwzp.service.StudentService;

public class StudentServiceImpl implements StudentService{

@Override
public String addStudent(String name) {
// System.out.println("开始添加学生"+name);
System.out.println("添加学生"+name);
// System.out.println("完成学生"+name+"的添加");
return name;
}

}

StudentService.java:

package com.wishwzp.service;

public interface StudentService {

public String addStudent(String name);
}

运行结果显示：

类名:com.wishwzp.service.impl.StudentServiceImpl
方法名：addStudent
开始添加学生：张三
添加学生前
添加学生张三
返回通知
张三
添加学生后
类名:com.wishwzp.service.impl.StudentServiceImpl
方法名：addStudent
学生添加完成：张三

5，异常通知；

T.java:

package com.wishwzp.test;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.wishwzp.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"?>
<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"> 
<!-- 注入bean，StudentServiceAspect -->
<bean id="studentServiceAspect" class="com.wishwzp.advice.StudentServiceAspect"></bean>

<!-- 注入bean，StudentServiceImpl -->
<bean id="studentService" class="com.wishwzp.service.impl.StudentServiceImpl"></bean>

<!-- 配置AOP -->
<aop:config>
<aop:aspect id="studentServiceAspect" ref="studentServiceAspect">
<!-- 配置执行切点路径和id -->
<aop:pointcut expression="execution(* com.wishwzp.service.*.*(..))" id="businessService"/>
<!-- 前置通知 -->
<aop:before method="doBefore" pointcut-ref="businessService"/>
<!-- 后置通知 -->
<aop:after method="doAfter" pointcut-ref="businessService"/>
<!-- 环绕通知 -->
<aop:around method="doAround" pointcut-ref="businessService"/>
<!-- 返回通知 -->
<aop:after-returning method="doAfterReturning" pointcut-ref="businessService"/>
<!-- 异常通知 -->
<aop:after-throwing method="doAfterThrowing" pointcut-ref="businessService" throwing="ex"/>
</aop:aspect>
</aop:config>
</beans>

StudentServiceAspect.java:

package com.wishwzp.advice;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;

public class StudentServiceAspect {

//前置通知
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("学生添加完成："+jp.getArgs()[0]);
}

//环绕通知,这里添加了返回值
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;
}

//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());
}
}

StudentServiceImpl.java:

package com.wishwzp.service.impl;

import com.wishwzp.service.StudentService;

public class StudentServiceImpl implements StudentService{

@Override
public String addStudent(String name) {
// System.out.println("开始添加学生"+name);
System.out.println("添加学生"+name);
System.out.println(1/0);
// System.out.println("完成学生"+name+"的添加");
return name;
}

}

StudentService.java:

package com.wishwzp.service;

public interface StudentService {

public String addStudent(String name);
}

运行结果显示：