Spring框架AOP使用扩展

一、什么是AOP

　　1、将复杂的需求分解出不同的方面，将散布在系统汇中的公共功能集中解决；

　　2、采用代理机制组装起来运行，再不改变原程序的基础上对代码段进行增强处理，增加新的功能；

　　3、默认采取的是JDK动态代理，面向接口编程的动态代理。

二、案例

　　接下来我们通过具体案例对AOP进一步了解

　　　　1、创建UserInfo实体类　

package com.spring.entity;

public class UserInfo {
    private Integer u_id;
    private String u_name;

    public Integer getU_id() {
        return u_id;
    }

    public void setU_id(Integer u_id) {
        this.u_id = u_id;
    }

    public String getU_name() {
        return u_name;
    }

    public void setU_name(String u_name) {
        this.u_name = u_name;
    }
}

　　2、创建IUserMapper接口，定义一个添加方法

package com.spring.mapper;

import com.spring.entity.UserInfo;

/**
 * Dao层接口
 */
public interface IUserMapper {
    //添加用户
    public int addUser(UserInfo info);
}

　　　创建IUserMapperImpl实现层

package com.spring.mapper.impl;

import com.spring.entity.UserInfo;
import com.spring.mapper.IUserMapper;

public class IUserMapperImpl implements IUserMapper {
    @Override
    public int addUser(UserInfo info) {
        System.out.println("add success");
        return 0;
    }
}

　　3、创建相对应的IUserMapperService接口，创建相同的方法

package com.spring.service;

import com.spring.entity.UserInfo;

public interface IUserMapperService {
    //添加用户
    public int addUser(UserInfo info);
}

　　4、创建Service的实现类IUserMapperServiceImpl类

package com.spring.service.impl;

import com.spring.entity.UserInfo;
import com.spring.mapper.IUserMapper;
import com.spring.service.IUserMapperService;

public class IUserMapperServiceImpl implements IUserMapperService {
   //注入Dao层对象
    private IUserMapper iUserMapper;

    public IUserMapper getiUserMapper() {
        return iUserMapper;
    }

    public void setiUserMapper(IUserMapper iUserMapper) {
        this.iUserMapper = iUserMapper;
    }

    @Override
    public int addUser(UserInfo info) {
        int count = iUserMapper.addUser(info);
        return count;
    }
}

　　5、在pom.xml中注入实现AOP的依赖

<dependency>
   <groupId>org.aspectj</groupId>
   <artifactId>aspectjweaver</artifactId>
   <version>1.7.0</version>
</dependency>

　　6、创建advice增强类MyBeforeAdvice

　　　　//MethodBeforeAdvice表示前置增强，在执行逻辑代码之前执行的操作
　　　　//AfterReturningAdvice表示后置增强，在逻辑代码执行完毕之后进行的操作

package com.spring.advice;

import org.springframework.aop.AfterReturningAdvice;
import org.springframework.aop.MethodBeforeAdvice;

import java.lang.reflect.Method;

public class MyBeforeAdvice implements MethodBeforeAdvice, AfterReturningAdvice {
    
    @Override
    public void before(Method method, Object[] objects, Object o) throws Throwable {
        System.out.println("==============前置增强，日志处理等操作===============");
    }

    @Override
    public void afterReturning(Object o, Method method, Object[] objects, Object o1) throws Throwable {
        System.out.println("==============后置操作，事务处理等操作================");
    }
}

　　7、配置applicationContextUser.xml文件

<?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"
       xmlns:p="http://www.springframework.org/schema/p"

       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">

   <!--声明DaoBean  bean的注入的都是实现类-->
    <bean id="iUserMapper" class="com.spring.mapper.impl.IUserMapperImpl"></bean>
    <!--声明Service      class:对应的是你的Service实现类-->
    <bean id="iUserMapperService" class="com.spring.service.impl.IUserMapperServiceImpl">
        <!--setter方法怎么注入：找到Name属性值，将属性值的开头改为大写，然后前缀加上setIUserMapper-->
        <property name="iUserMapper" ref="iUserMapper"></property>
     </bean>

    <!--切面：对应增强类-->
    <bean id="myBeforeAdvice" class="com.spring.advice.MyBeforeAdvice"></bean>
    
    <!--增强处理-->
    <aop:config>
        <!--切点：你要对哪一个方法进行增强     -->
        <aop:pointcut id="pointcut" expression="execution(* *..service.*.*(..))"/>

        <!--织入：将增强处理和切点表达式符合的方法关联到一起-->
        <aop:advisor advice-ref="myBeforeAdvice" pointcut-ref="pointcut"></aop:advisor>
    </aop:config>
</beans>

　　8、Test测试类　

package com.spring.Aop;

import com.spring.entity.Student;
import com.spring.entity.UserInfo;
import com.spring.service.IUserMapperService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class UserTest {
    public static void main(String[] args) {
        //加载applicationContext.xml文件
        ApplicationContext cxt=new ClassPathXmlApplicationContext("applicationContextUser.xml");
        IUserMapperService user = (IUserMapperService)cxt.getBean("iUserMapperService");
        user.addUser(new UserInfo());
    }
}

　　9、执行结果如下