为了甩锅，我写了个牛逼的日志切面！

架构师修炼

发布于 2022-05-17 12:36:43

4450

发布于 2022-05-17 12:36:43

文章被收录于专栏：架构师修炼架构师修炼

背景
切面介绍
切面的使用【基于注解】
动手写一个请求日志切面
高并发下请求日志切面

背景

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。

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
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<String, Object> getRequestParams(ProceedingJoinPoint proceedingJoinPoint) {
     Map<String, Object> 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<String, Object> getRequestParams(ProceedingJoinPoint proceedingJoinPoint) {
        Map<String, Object> 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。

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。

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<String, Object> 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<String, Object> 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<String, Object> buildRequestParam(String[] paramNames, Object[] paramValues) {
        Map<String, Object> 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。

地藏 Kelvin 的评论：关于 traceId 跟踪定位，可以根据 traceId 跟踪整条调用链，以 log4j2 为例介绍如何加入 traceId。

添加拦截器：

public class LogInterceptor implements HandlerInterceptor {
    private final static String TRACE_ID = "traceId";

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        String traceId = java.util.UUID.randomUUID().toString().replaceAll("-", "").toUpperCase();
        ThreadContext.put("traceId", traceId);

        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView)
            throws Exception {
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
            throws Exception {        
        ThreadContext. remove(TRACE_ID);
    }
}

在调用前通过 ThreadContext 加入 traceId，调用完成后移除。

修改日志配置文件：在原来的日志格式中添加 traceId 的占位符：

<property name="pattern">[TRACEID:%X{traceId}] %d{HH:mm:ss.SSS} %-5level %class{-1}.%M()/%L - %msg%xEx%n</property>

执行效果：

日志跟踪更方便，DMC 是配置 logback 和 log4j 使用的，使用方式和 ThreadContext 差不多，将 ThreadContext.put 替换为 MDC.put 即可，同时修改日志配置文件。

推荐使用 log4j2，log4j2 也是可以配合 MDC 一起使用的：

MDC 是 slf4j 包下的，其具体使用哪个日志框架与我们的依赖有关。

热心网友评论：if（value instanceof MultipartFile）这种流处理方式？但是如果参数碰到 List files 呢？这种处理方式好像就不行了哈。

确实代码有欠缺考虑的地方，解决方案如下：

//如果是批量文件上传
if (value instanceof List) {
     try {
        List<MultipartFile> multipartFiles = castList(value, MultipartFile.class);
        if (multipartFiles!= null) {
            List<String> fileNames = new ArrayList<>();
            for (MultipartFile file : multipartFiles) {
                fileNames.add(file.getOriginalFilename());
            }

            requestParams.put(paramNames[i], fileNames);
            break;
        }
    } catch (ClassCastException e) {
    //忽略不是文件类型的List
    }
}

对 List 的类型做一个判断，如果是文件 List，就进行遍历获取文件名。

其中 castList 方法为：

public static <T> List<T> castList(Object obj, Class<T> clazz) {
    List<T> result = new ArrayList<T>();
    if (obj instanceof List<?>) {
        for (Object o : (List<?>) obj) {
                result.add(clazz.cast(o));
        }
        return result;
    }
    return null;
}

修改后完整的代码为：

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

    @Pointcut("execution(* com.hikvision.trainplatform.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<String, Object> 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<String, Object> 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<String, Object> buildRequestParam(String[] paramNames, Object[] paramValues) {
        Map<String, Object> 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
            }

            //如果是批量文件上传
            if (value instanceof List) {
                System.out.println("Yes...");
                try {
                    List<MultipartFile> multipartFiles = castList(value, MultipartFile.class);
                    if (multipartFiles!= null) {
                        List<String> fileNames = new ArrayList<>();
                        for (MultipartFile file : multipartFiles) {
                            fileNames.add(file.getOriginalFilename());
                        }

                        requestParams.put(paramNames[i], fileNames);
                        break;
                    }
                } catch (ClassCastException e) {
                    //忽略不是文件类型的List
                }
            }

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

        return requestParams;
    }
    public static <T> List<T> castList(Object obj, Class<T> clazz) {
        List<T> result = new ArrayList<T>();
        if (obj instanceof List<?>) {
            for (Object o : (List<?>) obj) {
                result.add(clazz.cast(o));
            }
            return result;
        }
        return null;
    }

    @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;
    }
}

本文参与腾讯云自媒体分享计划，分享自微信公众号。

原始发表：2022-04-14 10:35:32，如有侵权请联系 cloudcommunity@tencent.com 删除

javascript