最近，前端开发把我恶心着了，为了甩锅，我写了个牛逼的日志切面！
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;
}
}
文章来源：https://c1n.cn/D5opM
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