//通过使用工具类RequestContextHolder拿到ServletRequestAttributes
ServletRequestAttributes requestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
//通过该实例方法获取到request对象
HttpServletRequest request = requestAttributes.getRequest();

<!--  web启动器：包含sping、springmvc、tomcat以及相关web集成工具、日志等  -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    <version>2.4.5</version>
</dependency>
<!--  若想使用AOP，需要引入该jar包进行切面  -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aspects</artifactId>
    <version>5.3.2</version>
</dependency>

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class SmartparkingApplication {
    public static void main(String[] args) {
        SpringApplication.run(com.SmartparkingApplication.class, args);
    }
}

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
/**
 * @ClassName HelloController
 * @Author ChangLu
 * @Date 2021/4/24 11:13
 * @Description TODO
 */
@Controller
public class HelloController {
    @RequestMapping("/hello")
    public String hello(){
        return "hello";  //跳转到template目录下的hello.html，方便快速测试我们可以不使用thymeleaf以及html文件，能够达到日志切面效果即可
    }
}

@Component
@Aspect
public class LogAspect {
    //对控制器包下的所有类方法进行切面
    @Pointcut("execution(* com.controller.*.*(..))")
    public void point(){}
    //前置通知
    @Before("point()")
    public void before(JoinPoint joinPoint){
        ServletRequestAttributes requestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();//通过工具类来获取到
        HttpServletRequest request = requestAttributes.getRequest();
        System.out.println(request.getSession());//session对象
        System.out.println(request.getMethod());//方法名
        System.out.println(request.getRequestURI());//请求路径(仅仅是被代理方法上的uri)
        System.out.println(request.getRequestURL());//完整请求路径
        System.out.println(request.getRemoteAddr());//可看做URI。返回发送请求的客户端或最后一个代理的Internet协议（IP）地址。 对于HTTP Servlet，与CGI变量REMOTE_ADDR的值相同
        System.out.println(request.getRemoteHost());//可看做URL。返回客户端或发送请求的最后一个代理的标准名称。 如果引擎无法或选择不解析主机名（以提高性能），则此方法返回IP地址的点分字符串形式。 对于HTTP Servlet，与CGI变量REMOTE_HOST的值相同。
        System.out.println(request.getRemotePort());//发送客户端的端口号
        System.out.println(request.getRemoteUser());//主机用户
        System.out.println(request.getContextPath());//上下文路径
    }
}

//首先通过RequestContextHolder请求上下文执行者拿到ServletRequestAttributes
//你可将ServletRequestAttributes看做是HttpServletRequest的容器，通过该容器存储
ServletRequestAttributes requestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
HttpServletRequest request = requestAttributes.getRequest();//获取请求对象
HttpServletResponse response = requestAttributes.getResponse();//获取相应对象

getRequestAttributes()=》ServletRequestAttributes
查看下RequestContextHolder的getRequestAttributes()方法：
public abstract class RequestContextHolder  {
  private static final boolean jsfPresent =
    ClassUtils.isPresent("javax.faces.context.FacesContext", RequestContextHolder.class.getClassLoader());
    //有两个ThreadLocal存储的就是请求对象
  private static final ThreadLocal<RequestAttributes> requestAttributesHolder =
    new NamedThreadLocal<>("Request attributes");
  private static final ThreadLocal<RequestAttributes> inheritableRequestAttributesHolder =
    new NamedInheritableThreadLocal<>("Request context");
    //调用方法获取到ThreadLocal中的RequestAttributes
    @Nullable
    public static RequestAttributes getRequestAttributes() {
       RequestAttributes attributes = requestAttributesHolder.get();
       if (attributes == null) {
          attributes = inheritableRequestAttributesHolder.get();
       }
       return attributes;
    }
}