定义接口

package service;

public interface UserService {

    void add();
    void delete();
    void update();
    void select();
}

接口实现类

package service;


public class UserServiceImpl implements UserService {
    public void add() {
        System.out.println("添加了一个用户");
    }

    public void delete() {
        System.out.println("删除了一个用户");
    }

    public void update() {
        System.out.println("更新了一个用户");
    }

    public void select() {
        System.out.println("查找了一个用户");
    }
}

1.通过原生Spring API接口实现

定义方法执行前通知

package Log;

import org.springframework.aop.MethodBeforeAdvice;

import java.lang.reflect.Method;

public class Log implements MethodBeforeAdvice {
    public void before(Method method, Object[] objects, Object o) throws Throwable {
        System.out.println(o.getClass().getName()+"的"+method.getName()+"方法被执行了");
    }
}

定义方法执行后通知

package Log;

import org.springframework.aop.AfterReturningAdvice;

import java.lang.reflect.Method;

public class MethodAfterAdvice implements AfterReturningAdvice {

    public void afterReturning(Object returnValue, Method method, Object[] args, Object target) throws Throwable {
        System.out.println(method.getName()+"被执行了，返回结果为"+returnValue);
    }
}

配置xml文件

<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
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/aop
        https://www.springframework.org/schema/aop/spring-aop.xsd">

    <bean id="userService" class="service.UserServiceImpl"/>
    <bean id="log" class="Log.Log"/>
    <bean id="after" class="Log.MethodAfterAdvice"/>
<!--    方式1使用原生Spring API接口-->
    <aop:config>
<!--        切入点：expression：表达式，execution（要执行的位置 * * * * *）-->
        <aop:pointcut id="pointcut" expression="execution(* service.UserServiceImpl.*(..))"/>

<!--        增加执行环绕-->
        <aop:advisor advice-ref="log" pointcut-ref="pointcut"/>
        <aop:advisor advice-ref="after" pointcut-ref="pointcut"/>


    </aop:config>
</beans>

2.通过自定义类

自定义类实现方法前调用函数和方法后调用函数

package diy;

public class DiyClass {

    //方法执行前调用函数
    public void before(){
        System.out.println("=====before======");
    }

    
    //方法执行后调用函数
    public void after(){
        System.out.println("=====after======");
    }
}

配置xml文件

<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
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/aop
        https://www.springframework.org/schema/aop/spring-aop.xsd">

    <bean id="userService" class="service.UserServiceImpl"/>

<!--    方式二自定义类-->
    <bean id="div" class="diy.DiyClass"/>

    <aop:config>
<!--        定义切入面-->
        <aop:aspect ref="div">
<!--            定义切入点-->
            <aop:pointcut id="point" expression="execution(* service.UserServiceImpl.*(..))"/>
<!--            定义通知-->
            <aop:before method="before" pointcut-ref="point"/>
            <aop:after method="after" pointcut-ref="point"/>
        </aop:aspect>
    </aop:config>
</beans>

通过注解实现

定义切面

package annotationAspect;

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.Signature;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;

@Aspect
public class AnnotationAspect {

    @Before("execution(* service.UserServiceImpl.*(..))")
    public void before(){
        System.out.println("=======before before=====");
    }

    @After("execution(* service.UserServiceImpl.*(..))")
    public void After(){
        System.out.println("=======After After=====");
    }

    @Around("execution(* service.UserServiceImpl.*(..))")
    public void around(ProceedingJoinPoint pj) throws Throwable {
        System.out.println("环绕前");
        Signature signature = pj.getSignature();
        System.out.println(signature);


        Object proceed = pj.proceed();//执行方法
        System.out.println("环绕后");

        System.out.println(proceed);
    }
}

配置文件

<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
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/aop
        https://www.springframework.org/schema/aop/spring-aop.xsd">

    <bean id="userService" class="service.UserServiceImpl"/>

<!--    方式三，通过注解实现aop-->
    <bean id="annotationAspect" class="annotationAspect.AnnotationAspect"/>
<!--    开启注解支持-->
    <aop:aspectj-autoproxy/>
</beans>

统一测试文件

import org.junit.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import service.UserService;
import service.UserServiceImpl;

public class Test1 {

    @Test
    public void test1(){
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");

        UserService service = (UserService) context.getBean("userService");
        System.out.println(service.hashCode());
        service.add();
        System.out.println(service.hashCode());
    }
}