Spring学习——Spring AOP和AspectJ

AOP实现

Spring AOP

与之前一篇一样的接口和实现类

1. 接口

package cn.edu.zucc.blog;

/**
 * 定义一个用户接口
 * @author xyj
 */
public interface UserDao {
    public void addUser();
    public void removeUser();
}

2. 实现类

package cn.edu.zucc.blog;

/**
 * userDao接口的实现类
 * @author xyj
 */
public class UserDaoImpl implements UserDao{
    @Override
    public void addUser() {
        System.out.println("this is addUser");
    }

    @Override
    public void removeUser() {
        System.out.println("this is removeUser");
    }
}

3.切面类

package cn.edu.zucc.blog.SpringAspect;

import org.aspectj.lang.ProceedingJoinPoint;

/**
 * 切面类
 * @author xyj
 */
public class SpringProxy {

    /**
     * 切面方法 arroud
     * 还有befor，after等其他可选方法
     */
    public Object myArround(ProceedingJoinPoint joinPoint) throws Throwable {
        //前置操作
        System.out.println("before method");
        //通过反射调用原有方法
        Object obj = joinPoint.proceed();
        //后置操作
        System.out.println("after method");
        return obj;
    }
}

4. aop.xml
   关于expression的公式可以参考https://blog.youkuaiyun.com/w605283073/article/details/82999927

<?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">

    <!--被代理的类-->
    <bean id="userdaoimpl" class="cn.edu.zucc.blog.UserDaoImpl"/>

    <!--切面类-->
    <bean id="springproxy" class="cn.edu.zucc.blog.SpringAspect.SpringProxy"/>

    <aop:config>
        <!--关联到切面方法-->
        <aop:aspect ref="springproxy">
            <!--设置切入点-->
            <aop:pointcut id="myPointcut" expression="execution(* cn.edu.zucc.blog.UserDao.*(..))"/>
            <!--设置切面方法这里的方法名要与切面类中定义的方法名一致-->
            <aop:around method="myArround" pointcut-ref="myPointcut"/>
        </aop:aspect>
    </aop:config>
</beans>

6. Test测试类

package cn.edu.zucc.blog.SpringAspect;

import cn.edu.zucc.blog.UserDao;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Test {
    public static void main(String[] args) {
        //导入xml配置文件
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("aop.xml");
        //通过Ioc获取代理对象
        UserDao user = (UserDao) applicationContext.getBean("userdaoimpl");
        //调用方法
        user.addUser();
        user.removeUser();
    }
}

注解写入

1. 接口与实现类不变
2. 切面类加入注解

package cn.edu.zucc.blog.SpringAspect;

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;

/**
 * 切面类
 * @author xyj
 */
@Aspect
public class SpringProxy2 {

    /**
     * 切面方法 arroud
     * 还有befor，after等其他可选方法
     */
    @Around("execution(* cn.edu.zucc.blog.UserDao.*(..))")
    public Object myArround(ProceedingJoinPoint joinPoint) throws Throwable {
        //前置操作
        System.out.println("before method");
        //通过反射调用原有方法
        Object obj = joinPoint.proceed();
        //后置操作
        System.out.println("after method");
        return obj;
    }
}

3. 配置文件删除重复配置

<?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.xsd">
    <!--被代理的类-->
    <bean id="userdaoimpl" class="cn.edu.zucc.blog.UserDaoImpl"/>

    <!--切面类-->
    <bean id="springproxy2" class="cn.edu.zucc.blog.SpringAspect.SpringProxy2"/>
    
    <aop:aspectj-autoproxy></aop:aspectj-autoproxy>
</beans>

4. Test测试

package cn.edu.zucc.blog.SpringAspect;

import cn.edu.zucc.blog.UserDao;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Test2 {
    public static void main(String[] args) {
        //导入xml配置文件
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("aop2.xml");
        //通过Ioc获取代理对象
        UserDao user = (UserDao) applicationContext.getBean("userdaoimpl");
        //调用方法
        user.addUser();
        user.removeUser();
    }
}

还是通过注解最简单啊！在这里只实现了around，其他的before，after等大同小异，可自行了解