使用Spring的API接口实现AOP

引入AOP的依赖

<!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
<dependency>
    <groupId>org.aspectj</groupId>
    <artifactId>aspectjweaver</artifactId>
    <version>1.9.4</version>
</dependency>

Service接口

package com.ledao.service;

/**
 * @author LeDao
 * @company
 * @create 2022-02-17 20:29
 */
public interface StudentService {

    /**
     * 添加学生
     */
    void add();

    /**
     * 删除学生
     */
    void delete();

    /**
     * 修改学生
     */
    void update();

    /**
     * 根据id查找学生
     */
    void findById();
}

Service接口实现类

package com.ledao.service.impl;

import com.ledao.service.StudentService;

/**
 * @author LeDao
 * @company
 * @create 2022-02-17 20:30
 */
public class StudentServiceImpl implements StudentService {

    @Override
    public void add() {
        System.out.println("添加学生");
    }

    @Override
    public void delete() {
        System.out.println("删除学生");
    }

    @Override
    public void update() {
        System.out.println("修改学生");
    }

    @Override
    public void findById() {
        System.out.println("根据id查找学生");
    }
}

定义增强类

Log前置增强类

执行业务代码前先执行

package com.ledao.log;

import org.springframework.aop.MethodBeforeAdvice;

import java.lang.reflect.Method;

/**
 * @author LeDao
 * @company
 * @create 2022-02-17 21:10
 */
public class BeforeLog implements MethodBeforeAdvice {

    /**
     * 执行业务代码前先执行
     *
     * @param method 要执行的目标对象的方法
     * @param args   参数
     * @param target 目标对象
     * @throws Throwable
     */
    @Override
    public void before(Method method, Object[] args, Object target) throws Throwable {
        if (target != null) {
            System.out.println("[BeforeLog]" + target.getClass().getName() + "下的" + method.getName() + "方法被执行了");
        }
    }
}

Log后置增强类

执行业务代码后再执行

package com.ledao.log;

import org.springframework.aop.AfterReturningAdvice;

import java.lang.reflect.Method;

/**
 * @author LeDao
 * @company
 * @create 2022-02-17 21:14
 */
public class AfterLog implements AfterReturningAdvice {

    /**
     * 执行业务代码后再执行
     *
     * @param returnValue 返回值
     * @param method      要执行的目标对象的方法
     * @param args        参数
     * @param target      目标对象
     * @throws Throwable
     */
    @Override
    public void afterReturning(Object returnValue, Method method, Object[] args, Object target) throws Throwable {
        System.out.println("[AfterLog]执行了" + method.getName() + "方法,返回结果为:" + returnValue);
    }
}

配置文件ApplicationContext.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
        https://www.springframework.org/schema/aop/spring-aop.xsd">

    <!--注册bean-->
    <bean id="studentService" class="com.ledao.service.impl.StudentServiceImpl"/>
    <bean id="beforeLog" class="com.ledao.log.BeforeLog"/>
    <bean id="afterLog" class="com.ledao.log.AfterLog"/>

    <!--配置AOP-->
    <aop:config>
        <!--切入点：expression：表达式，execution(要执行的位置！* * * * *)-->
        <aop:pointcut id="pointcut" expression="execution(* com.ledao.service.impl.StudentServiceImpl.*(..))"/>
        <!--执行环绕增加！-->
        <aop:advisor advice-ref="beforeLog" pointcut-ref="pointcut"/>
        <aop:advisor advice-ref="afterLog" pointcut-ref="pointcut"/>
    </aop:config>
</beans>

测试

import com.ledao.service.StudentService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * @author LeDao
 * @company
 * @create 2022-02-12 15:56
 */
public class MyTest {

    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("ApplicationContext.xml");
        StudentService studentService = context.getBean("studentService", StudentService.class);
        studentService.add();
    }
}