写个日志切面追踪，可以更直接查看项目执行的各种信息打印。

项目在进入联调阶段时，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

 

切面介绍

面向切面编程是一种编程范式，是作为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：

 

• 可以集中处理某一关注点/横切逻辑

• 可以很方便的添加或者删除关注点

• 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

1-1 首先使用@Pointcut定义一个切点，因为是请求日志切边，因此切点定义的是Controller包下的所有类下的所有方法，

定义以后就在通知注解中直接使用requestServer方法即可

//定义切点
@Pointcut("execution(* com.xxx.xxx.controller..*(..))")
public void requestServer() {
}

1.2 执行Controller的方法前打印调用方IP、请求URL、HTTP请求类型、调用的方法名

@Before("requestServer()")      //这里使用的注解里面的方法就是之前定义的切点
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());
}

1.3 使用@Around注解打印进入控制层(Controller)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;
}

 1.4 打印了入参、结果以及耗时 ---- getRequestParams 方法。

 通过@PathVariable以及@RequestParam注解传递的参数无法直接打印参数名，需要手动拼接参数名以及需要对文件对象进行特殊处理，仅获取文件名

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;
 }

1.5 @After：方法调用后执行，仅仅只是通知方法执行完毕的结尾

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

完整的切面类代码，包含上面所有定义的类，但是不建议放一起，避免耦合

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

    @Pointcut("execution(* xxx.xxx.xx.controller..*(..))")            //注意这里是你自己项目结构
    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];

            //判断是否为文件对象
            if (value instanceof MultipartFile) {
                MultipartFile file = (MultipartFile) value;
                value = file.getOriginalFilename();  //获取文件名
            }

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

        return requestParams;
    }
}

分析：如果按照上面的方式进行日志追踪，正常情况下是没有问题的，但是如果是在高并发的情况下使用则会出现日志打印串行的问题，所以接下来是高并发下的处理方案，如生产环境有高并发的情况则需要下面的一些补充和设置

 1、首先创建一个参数信息类(RequestInfo)，定义需要的参数

@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;
}

2.1、定义环绕方法通知体，将参数信息封装成RequestInfo对象，然后序列化打印对象，这样可以更加清晰直接查看打印信息，而且在解决串行问题的同时添加了对异常信息的打印，通过使用@AfterThrowing注解对抛出异常的方法进行处理

//这是封装RequestInfo对象信息类
@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;
}

2.2、异常类参数信息定义

//异常参数类定义
@Data
public class RequestErrorInfo {
    private String ip;
    private String url;
    private String httpMethod;
    private String classMethod;
    private Object requestParams;
    private RuntimeException exception;
}

2.3、出现异常时，打印耗时是没太大意义的，只需要获取异常信息即可

//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));
}

完整的日志切面代码，包含参数定义类、异常处理类所有代码，但是不建议放一起，避免耦合

@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;
    }
}