写个日志请求切面，前后端甩锅更方便

最近项目进入联调阶段，服务层的接口需要和协议层进行交互，协议层需要将入参[json字符串]组装成服务层所需的json字符串，组装的过程中很容易出错。入参出错导致接口调试失败问题在联调中出现很多次，因此就想写一个请求日志切面把入参信息打印一下，同时协议层调用服务层接口名称对不上也出现了几次，通过请求日志切面就可以知道上层是否有没有发起调用，方便前后端甩锅还能拿出证据

写在前面

本篇文章是实战性的，对于切面的原理不会讲解，只会简单介绍一下切面的知识点

切面介绍

面向切面编程是一种编程范式，它作为OOP面向对象编程的一种补充，用于处理系统中分布于各个模块的横切关注点，比如事务管理、权限控制、缓存控制、日志打印等等。
AOP把软件的功能模块分为两个部分：核心关注点和横切关注点。业务处理的主要功能为核心关注点，而非核心、需要拓展的功能为横切关注点。AOP的作用在于分离系统中的各种关注点，将核心关注点和横切关注点进行分离，使用切面有以下好处：

• 集中处理某一关注点/横切逻辑
• 可以很方便的添加/删除关注点
• 侵入性少，增强代码可读性及可维护性
  因此当想打印请求日志时很容易想到切面，对控制层代码0侵入

切面的使用【基于注解】

• @Aspect => 声明该类为一个注解类

切点注解：

• @Pointcut => 定义一个切点，可以简化代码

通知注解：

• @Before => 在切点之前执行代码
• @After => 在切点之后执行代码
• @AfterReturning => 切点返回内容后执行代码，可以对切点的返回值进行封装
• @AfterThrowing => 切点抛出异常后执行
• @Around => 环绕，在切点前后执行代码

动手写一个请求日志切面

• 使用@Pointcut定义切点

  @Pointcut("execution(* your_package.controller..*(..))")
  public void requestServer() {
  }
  

  @Pointcut定义了一个切点，因为是请求日志切边，因此切点定义的是Controller包下的所有类下的方法。定义切点以后在通知注解中直接使用requestServer方法名就可以了
• 使用@Before再切点前执行

  @Before("requestServer()")
  public void doBefore(JoinPoint joinPoint) {
      ServletRequestAttributes attributes = (ServletRequestAttributes) 
  RequestContextHolder.getRequestAttributes();
      HttpServletRequest request = attributes.getRequest();
  
      LOGGER.info("===============================Start========================");
      LOGGER.info("IP                 : {}", request.getRemoteAddr());
      LOGGER.info("URL                : {}", request.getRequestURL().toString());
      LOGGER.info("HTTP Method        : {}", request.getMethod());
      LOGGER.info("Class Method       : {}.{}", joinPoint.getSignature().getDeclaringTypeName(), joinPoint.getSignature().getName());
  }
  

  在进入Controller方法前，打印出调用方IP、请求URL、HTTP请求类型、调用的方法名
• 使用@Around打印进入控制层的入参

  @Around("requestServer()")
  public Object doAround(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
      long start = System.currentTimeMillis();
      Object result = proceedingJoinPoint.proceed();
      LOGGER.info("Request Params       : {}", getRequestParams(proceedingJoinPoint));
      LOGGER.info("Result               : {}", result);
      LOGGER.info("Time Cost            : {} ms", System.currentTimeMillis() - start);
  
      return result;
  }
  

  打印了入参、结果以及耗时
  • getRquestParams方法

    private Map getRequestParams(ProceedingJoinPoint proceedingJoinPoint) {
         Map requestParams = new HashMap<>();
    
          //参数名
         String[] paramNames = ((MethodSignature)proceedingJoinPoint.getSignature()).getParameterNames();
         //参数值
         Object[] paramValues = proceedingJoinPoint.getArgs();
    
         for (int i = 0; i < paramNames.length; i++) {
             Object value = paramValues[i];
    
             //如果是文件对象
             if (value instanceof MultipartFile) {
                 MultipartFile file = (MultipartFile) value;
                 value = file.getOriginalFilename();  //获取文件名
             }
    
             requestParams.put(paramNames[i], value);
         }
    
         return requestParams;
     }
    

    通过 @PathVariable以及@RequestParam注解传递的参数无法打印出参数名，因此需要手动拼接一下参数名，同时对文件对象进行了特殊处理，只需获取文件名即可
• @After方法调用后执行

  @After("requestServer()")
  public void doAfter(JoinPoint joinPoint) {
      LOGGER.info("===============================End========================");
  }
  

没有业务逻辑只是打印了End

• 完整切面代码

  @Component
  @Aspect
  public class RequestLogAspect {
      private final static Logger LOGGER = LoggerFactory.getLogger(RequestLogAspect.class);
  
      @Pointcut("execution(* your_package.controller..*(..))")
      public void requestServer() {
      }
  
      @Before("requestServer()")
      public void doBefore(JoinPoint joinPoint) {
          ServletRequestAttributes attributes = (ServletRequestAttributes) 
  RequestContextHolder.getRequestAttributes();
          HttpServletRequest request = attributes.getRequest();
  
          LOGGER.info("===============================Start========================");
          LOGGER.info("IP                 : {}", request.getRemoteAddr());
          LOGGER.info("URL                : {}", request.getRequestURL().toString());
          LOGGER.info("HTTP Method        : {}", request.getMethod());
          LOGGER.info("Class Method       : {}.{}", joinPoint.getSignature().getDeclaringTypeName(), 
   joinPoint.getSignature().getName());
      }
  
  
      @Around("requestServer()")
      public Object doAround(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
          long start = System.currentTimeMillis();
          Object result = proceedingJoinPoint.proceed();
          LOGGER.info("Request Params     : {}", getRequestParams(proceedingJoinPoint));
          LOGGER.info("Result               : {}", result);
          LOGGER.info("Time Cost            : {} ms", System.currentTimeMillis() - start);
  
          return result;
      }
  
      @After("requestServer()")
      public void doAfter(JoinPoint joinPoint) {
          LOGGER.info("===============================End========================");
      }
  
      /**
       * 获取入参
       * @param proceedingJoinPoint
       *
       * @return
       * */
      private Map getRequestParams(ProceedingJoinPoint proceedingJoinPoint) {
          Map requestParams = new HashMap<>();
  
          //参数名
          String[] paramNames = 
  ((MethodSignature)proceedingJoinPoint.getSignature()).getParameterNames();
          //参数值
          Object[] paramValues = proceedingJoinPoint.getArgs();
  
          for (int i = 0; i < paramNames.length; i++) {
              Object value = paramValues[i];
  
              //如果是文件对象
              if (value instanceof MultipartFile) {
                  MultipartFile file = (MultipartFile) value;
                  value = file.getOriginalFilename();  //获取文件名
              }
  
              requestParams.put(paramNames[i], value);
          }
  
          return requestParams;
      }
  }
  

高并发下请求日志切面

写完以后对自己的代码很满意，但是想着可能还有完善的地方就和朋友交流了一下。emmmm

image

果然还有继续优化的地方
每个信息都打印一行，在高并发请求下确实会出现请求之间打印日志串行的问题，因为测试阶段请求数量较少没有出现串行的情况，果然生产环境才是第一发展力，能够遇到更多bug，写更健壮的代码
解决日志串行的问题只要将多行打印信息合并为一行就可以了，因此构造一个对象

• RequestInfo.java

  @Data
  public class RequestInfo {
      private String ip;
      private String url;
      private String httpMethod;
      private String classMethod;
      private Object requestParams;
      private Object result;
      private Long timeCost;
  }
  

• 环绕通知方法体

  @Around("requestServer()")
  public Object doAround(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
      long start = System.currentTimeMillis();
      ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
      HttpServletRequest request = attributes.getRequest();
      Object result = proceedingJoinPoint.proceed();
      RequestInfo requestInfo = new RequestInfo();
              requestInfo.setIp(request.getRemoteAddr());
      requestInfo.setUrl(request.getRequestURL().toString());
      requestInfo.setHttpMethod(request.getMethod());
      requestInfo.setClassMethod(String.format("%s.%s", proceedingJoinPoint.getSignature().getDeclaringTypeName(),
              proceedingJoinPoint.getSignature().getName()));
      requestInfo.setRequestParams(getRequestParamsByProceedingJoinPoint(proceedingJoinPoint));
      requestInfo.setResult(result);
      requestInfo.setTimeCost(System.currentTimeMillis() - start);
      LOGGER.info("Request Info      : {}", JSON.toJSONString(requestInfo));
  
      return result;
  }
  

  将url、http request这些信息组装成RequestInfo对象，再序列化打印对象
  打印序列化对象结果而不是直接打印对象是因为序列化有更直观、更清晰，同时可以借助在线解析工具对结果进行解析

image

是不是还不错
在解决高并发下请求串行问题的同时添加了对异常请求信息的打印，通过使用 @AfterThrowing注解对抛出异常的方法进行处理

• RequestErrorInfo.java

  @Data
  public class RequestErrorInfo {
      private String ip;
      private String url;
      private String httpMethod;
      private String classMethod;
      private Object requestParams;
      private RuntimeException exception;
  }
  

• 异常通知环绕体

  @AfterThrowing(pointcut = "requestServer()", throwing = "e")
  public void doAfterThrow(JoinPoint joinPoint, RuntimeException e) {
      ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
      HttpServletRequest request = attributes.getRequest();
      RequestErrorInfo requestErrorInfo = new RequestErrorInfo();
      requestErrorInfo.setIp(request.getRemoteAddr());
      requestErrorInfo.setUrl(request.getRequestURL().toString());
      requestErrorInfo.setHttpMethod(request.getMethod());
      requestErrorInfo.setClassMethod(String.format("%s.%s", joinPoint.getSignature().getDeclaringTypeName(),
              joinPoint.getSignature().getName()));
      requestErrorInfo.setRequestParams(getRequestParamsByJoinPoint(joinPoint));
      requestErrorInfo.setException(e);
      LOGGER.info("Error Request Info      : {}", JSON.toJSONString(requestErrorInfo));
  }
  

  对于异常，耗时是没有意义的，因此不统计耗时，而是添加了异常的打印

最后放一下完整日志请求切面代码：

@Component
@Aspect
public class RequestLogAspect {
    private final static Logger LOGGER = LoggerFactory.getLogger(RequestLogAspect.class);

    @Pointcut("execution(* your_package.controller..*(..))")
    public void requestServer() {
    }

    @Around("requestServer()")
    public Object doAround(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
        long start = System.currentTimeMillis();
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = attributes.getRequest();
        Object result = proceedingJoinPoint.proceed();
        RequestInfo requestInfo = new RequestInfo();
                requestInfo.setIp(request.getRemoteAddr());
        requestInfo.setUrl(request.getRequestURL().toString());
        requestInfo.setHttpMethod(request.getMethod());
        requestInfo.setClassMethod(String.format("%s.%s", proceedingJoinPoint.getSignature().getDeclaringTypeName(),
                proceedingJoinPoint.getSignature().getName()));
        requestInfo.setRequestParams(getRequestParamsByProceedingJoinPoint(proceedingJoinPoint));
        requestInfo.setResult(result);
        requestInfo.setTimeCost(System.currentTimeMillis() - start);
        LOGGER.info("Request Info      : {}", JSON.toJSONString(requestInfo));

        return result;
    }


    @AfterThrowing(pointcut = "requestServer()", throwing = "e")
    public void doAfterThrow(JoinPoint joinPoint, RuntimeException e) {
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = attributes.getRequest();
        RequestErrorInfo requestErrorInfo = new RequestErrorInfo();
        requestErrorInfo.setIp(request.getRemoteAddr());
        requestErrorInfo.setUrl(request.getRequestURL().toString());
        requestErrorInfo.setHttpMethod(request.getMethod());
        requestErrorInfo.setClassMethod(String.format("%s.%s", joinPoint.getSignature().getDeclaringTypeName(),
                joinPoint.getSignature().getName()));
        requestErrorInfo.setRequestParams(getRequestParamsByJoinPoint(joinPoint));
        requestErrorInfo.setException(e);
        LOGGER.info("Error Request Info      : {}", JSON.toJSONString(requestErrorInfo));
    }

    /**
     * 获取入参
     * @param proceedingJoinPoint
     *
     * @return
     * */
    private Map getRequestParamsByProceedingJoinPoint(ProceedingJoinPoint proceedingJoinPoint) {
        //参数名
        String[] paramNames = ((MethodSignature)proceedingJoinPoint.getSignature()).getParameterNames();
        //参数值
        Object[] paramValues = proceedingJoinPoint.getArgs();

        return buildRequestParam(paramNames, paramValues);
    }

    private Map getRequestParamsByJoinPoint(JoinPoint joinPoint) {
        //参数名
        String[] paramNames = ((MethodSignature)joinPoint.getSignature()).getParameterNames();
        //参数值
        Object[] paramValues = joinPoint.getArgs();

        return buildRequestParam(paramNames, paramValues);
    }

    private Map buildRequestParam(String[] paramNames, Object[] paramValues) {
        Map requestParams = new HashMap<>();
        for (int i = 0; i < paramNames.length; i++) {
            Object value = paramValues[i];

            //如果是文件对象
            if (value instanceof MultipartFile) {
                MultipartFile file = (MultipartFile) value;
                value = file.getOriginalFilename();  //获取文件名
            }

            requestParams.put(paramNames[i], value);
        }

        return requestParams;
    }

    @Data
    public class RequestInfo {
        private String ip;
        private String url;
        private String httpMethod;
        private String classMethod;
        private Object requestParams;
        private Object result;
        private Long timeCost;
    }

    @Data
    public class RequestErrorInfo {
        private String ip;
        private String url;
        private String httpMethod;
        private String classMethod;
        private Object requestParams;
        private RuntimeException exception;
    }
}

赶紧给你们的应用加上吧【如果没加的话】，没有日志的话，总怀疑上层出错，但是却拿不出证据