一、引入依赖

<!--引入AOP依赖-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-aop</artifactId>
</dependency>

:::warning 注意：在完成了引入AOP依赖包后，不需要去做其他配置。AOP的默认配置属性中，spring.aop.auto属性默认是开启的，也就是说只要引入了AOP依赖后，默认已经增加了@EnableAspectJAutoProxy，不需要在程序主类中增加@EnableAspectJAutoProxy来启用。 :::

二、定义切面

定义切面类：在类上添加@Aspect 和@Component 注解即可将一个类定义为切面类。
@Aspect 注解使之成为切面类
@Component 注解把切面类加载到到IOC容器中，Bean交给Spring容器管理

package com.king.aop.aspect;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import javax.servlet.http.HttpServletRequest;
import java.util.Arrays;
import java.util.Objects;
/**
 * 日志切面
 * @PackageName com.king.aop.aspect
 * @ClassName LogAspect
 * @Auther jgg
 * @Date 2021-7-5 10:16
 */
@Aspect
@Component
public class LogAspect {
    private static final Logger logger = LoggerFactory.getLogger(LogAspect.class);
    @Pointcut("execution(public * com.king.aop.controller.*.*(..))")
    public void webLog(){}
    /*前置通知*/
    @Before("webLog()")
    public void doBefore(JoinPoint joinPoint) throws Throwable{
        //接收到请求，记录请求信息
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        HttpServletRequest request= attributes.getRequest();
        //记录请求信息
        System.out.println("URL" + request.getRequestURL().toString());
        System.out.println("request.getMethod() = " + request.getMethod());
        System.out.println("IP:" + request.getRemoteHost());
        System.out.println("Class+Methord" + joinPoint.getSignature().getDeclaringTypeName() + "." + joinPoint.getSignature().getName());
        System.out.println("params" + Arrays.toString(joinPoint.getArgs()));
        logger.info("user ip: {}",request.getRemoteAddr());
   }
    //后置异常通知
    @AfterThrowing("webLog()")
    public void throwss(JoinPoint jp){
        System.out.println("方法异常时执行...");
    }
    //后置最终通知,final增强，不管是抛出异常或者正常退出都会执行
    @After("webLog()")
    public void after(JoinPoint jp){
        System.out.println("方法最后执行...");
    }
    @AfterReturning(returning = "obj",pointcut = "webLog()")
    public void doAfterReturing(Objects obj) throws Throwable{
        System.out.println("方法返回值为:"+obj);
        logger.info("方法返回值为: {}",obj);
    }
    /**
     * 环绕通知
     * @param point
     * @throws Throwable
     */
    @Around("webLog()")
    public void doAround(ProceedingJoinPoint point) throws Throwable{
        System.out.println("方法环绕Running...");
        try {
            Object proceed = point.proceed();
            System.out.println("方法环绕proceed，结果是 :" + proceed);
            logger.info("方法返回值:{}",proceed);
        } catch (Throwable throwable) {
            throw throwable;
        }
    }
}

采用自定义注解的形式实现 Spring AOP

自定义注解

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
 * @PackageName com.king.aop.aspect
 * @ClassName UserAspect
 * @Auther jgg
 * @Date 2021-7-6 9:31
 */
@Target({ElementType.METHOD,ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface UserAccess {
    String desc() default "No Data!";
}

定义切面

package com.king.aop.aspect;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.*;
import org.springframework.stereotype.Component;
import java.util.Date;
/**
 * @PackageName com.king.aop.aspect
 * @ClassName UserAccessAspect
 * @Auther jgg
 * @Date 2021-7-6 9:35
 */
@Component
@Aspect
public class UserAccessAspect {
    @Pointcut(value ="@annotation(com.king.aop.aspect.UserAccess)")
    public void access(){
    }
    @Before("access()")
    public void doBefore(JoinPoint point){
        System.out.println("-aop 日志记录启动-" + new Date());
    }
    /*环绕通知*/
    @Around("@annotation(userAccess)")
    public Object around(ProceedingJoinPoint pjp, UserAccess userAccess) {
        //获取注解里的值
        System.out.println("second around:" + userAccess.desc());
        try {
            return pjp.proceed();
        } catch (Throwable throwable) {
            throwable.printStackTrace();
            return null;
        }
    }
    //进来切点这，最后经过的一个站，也是方法正常运行结束后
    @After("access()")
    public void after(JoinPoint joinPoint) {
        System.out.println("-aop 日志记录结束-" + new Date());
    }
}

三、知识补充

切点表达式

https://www.cnblogs.com/javazhiyin/p/9993299.html
原文链接：https://blog.csdn.net/qq_35387940/article/details/85261279
https://www.cnblogs.com/zhangxufeng/p/9160869.html

学习文档

SpringBoot--aop