SpringBoot實戰 之 接口日誌篇
阿新 • • 發佈：2018-01-24
empty 工具 argument contains art utm ioe strong exception
在本篇文章中不會詳細介紹日誌如何配置、如果切換另外一種日誌工具之類的內容，只用於記錄作者本人在工作過程中對日誌的幾種處理方式。
1. Debug 日誌管理
在開發的過程中，總會遇到各種莫名其妙的問題，而這些問題的定位一般會使用到兩種方式，第一種是通過手工 Debug 代碼，第二種則是直接查看日誌輸出。Debug 代碼這種方式只能在 IDE 下使用，一旦程序移交部署，就只能通過日誌來跟蹤定位了。
在測試環境下，我們無法使用 Debug 代碼來定位問題，所以這時候需要記錄所有請求的參數及對應的響應報文。而在 數據交互篇 中，我們將請求及響應的格式都定義成了Json，而且傳輸的數據還是存放在請求體裏面。而請求體對應在 HttpServletRequest 裏面又只是一個輸入流，這樣的話，就無法在過濾器或者攔截器裏面去做日誌記錄了，而必須要等待輸入流轉換成請求模型後（響應對象轉換成輸出流前）做數據日誌輸出。
有目標那就好辦了，只需要找到轉換發生的地方就可以植入我們的日誌了。通過源碼的閱讀，終於在 AbstractMessageConverterMethodArgumentResolver 個類中發現了我們的期望的那個地方，對於請求模型的轉換，實現代碼如下：
@SuppressWarnings("unchecked")
protected <T> Object readWithMessageConverters(HttpInputMessage inputMessage, MethodParameter parameter,
Type targetType) throws IOException, HttpMediaTypeNotSupportedException, HttpMessageNotReadableException {
MediaType contentType;
boolean noContentType = false;
try {
contentType = inputMessage.getHeaders().getContentType();
}
catch (InvalidMediaTypeException ex) {
throw new HttpMediaTypeNotSupportedException(ex.getMessage());
}
if (contentType == null) {
noContentType = true;
contentType = MediaType.APPLICATION_OCTET_STREAM;
}
Class<?> contextClass = (parameter != null ? parameter.getContainingClass() : null);
Class<T> targetClass = (targetType instanceof Class ? (Class<T>) targetType : null);
if (targetClass == null) {
ResolvableType resolvableType = (parameter != null ?
ResolvableType.forMethodParameter(parameter) : ResolvableType.forType(targetType));
targetClass = (Class<T>) resolvableType.resolve();
}
HttpMethod httpMethod = ((HttpRequest) inputMessage).getMethod();
Object body = NO_VALUE;
try {
inputMessage = new EmptyBodyCheckingHttpInputMessage(inputMessage);
for (HttpMessageConverter<?> converter : this.messageConverters) {
Class<HttpMessageConverter<?>> converterType = (Class<HttpMessageConverter<?>>) converter.getClass();
if (converter instanceof GenericHttpMessageConverter) {
GenericHttpMessageConverter<?> genericConverter = (GenericHttpMessageConverter<?>) converter;
if (genericConverter.canRead(targetType, contextClass, contentType)) {
if (logger.isDebugEnabled()) {
logger.debug("Read [" + targetType + "] as \"" + contentType + "\" with [" + converter + "]");
}
if (inputMessage.getBody() != null) {
inputMessage = getAdvice().beforeBodyRead(inputMessage, parameter, targetType, converterType);
body = genericConverter.read(targetType, contextClass, inputMessage);
body = getAdvice().afterBodyRead(body, inputMessage, parameter, targetType, converterType);
}
else {
body = getAdvice().handleEmptyBody(null, inputMessage, parameter, targetType, converterType);
}
break;
}
}
else if (targetClass != null) {
if (converter.canRead(targetClass, contentType)) {
if (logger.isDebugEnabled()) {
logger.debug("Read [" + targetType + "] as \"" + contentType + "\" with [" + converter + "]");
}
if (inputMessage.getBody() != null) {
inputMessage = getAdvice().beforeBodyRead(inputMessage, parameter, targetType, converterType);
body = ((HttpMessageConverter<T>) converter).read(targetClass, inputMessage);
body = getAdvice().afterBodyRead(body, inputMessage, parameter, targetType, converterType);
}
else {
body = getAdvice().handleEmptyBody(null, inputMessage, parameter, targetType, converterType);
}
break;
}
}
}
}
catch (IOException ex) {
throw new HttpMessageNotReadableException("Could not read document: " + ex.getMessage(), ex);
}
if (body == NO_VALUE) {
if (httpMethod == null || !SUPPORTED_METHODS.contains(httpMethod) ||
(noContentType && inputMessage.getBody() == null)) {
return null;
}
throw new HttpMediaTypeNotSupportedException(contentType, this.allSupportedMediaTypes);
}
return body;
}
上面的代碼中有一處非常重要的地方，那就在在數據轉換前後都存在 Advice 相關的方法調用，顯然，只需要在 Advice 裏面完成日誌記錄就可以了，下面開始實現自定義 Advice。
首先，請求體日誌切面 LogRequestBodyAdvice 實現如下：
@ControllerAdvice
public class LogRequestBodyAdvice implements RequestBodyAdvice {
private Logger logger = LoggerFactory.getLogger(LogRequestBodyAdvice.class);
@Override
public boolean supports(MethodParameter methodParameter, Type targetType,
Class<? extends HttpMessageConverter<?>> converterType) {
return true;
}
@Override
public Object handleEmptyBody(Object body, HttpInputMessage inputMessage,
MethodParameter parameter, Type targetType,
Class<? extends HttpMessageConverter<?>> converterType) {
return body;
}
@Override
public HttpInputMessage beforeBodyRead(HttpInputMessage inputMessage,
MethodParameter parameter, Type targetType,
Class<? extends HttpMessageConverter<?>> converterType) throws IOException {
return inputMessage;
}
@Override
public Object afterBodyRead(Object body, HttpInputMessage inputMessage,
MethodParameter parameter, Type targetType,
Class<? extends HttpMessageConverter<?>> converterType) {
Method method = parameter.getMethod();
String classMappingUri = getClassMappingUri(method.getDeclaringClass());
String methodMappingUri = getMethodMappingUri(method);
if (!methodMappingUri.startsWith("/")) {
methodMappingUri = "/" + methodMappingUri;
}
logger.debug("uri={} | requestBody={}", classMappingUri + methodMappingUri, JSON.toJSONString(body));
return body;
}
private String getMethodMappingUri(Method method) {
RequestMapping methodDeclaredAnnotation = method.getDeclaredAnnotation(RequestMapping.class);
return methodDeclaredAnnotation == null ? "" : getMaxLength(methodDeclaredAnnotation.value());
}
private String getClassMappingUri(Class<?> declaringClass) {
RequestMapping classDeclaredAnnotation = declaringClass.getDeclaredAnnotation(RequestMapping.class);
return classDeclaredAnnotation == null ? "" : getMaxLength(classDeclaredAnnotation.value());
}
private String getMaxLength(String[] strings) {
String methodMappingUri = "";
for (String string : strings) {
if (string.length() > methodMappingUri.length()) {
methodMappingUri = string;
}
}
return methodMappingUri;
}
}
得到日誌記錄如下：
2017-05-02 22:48:15.435 DEBUG 888 --- [nio-8080-exec-1] c.q.funda.advice.LogRequestBodyAdvice : uri=/sys/user/login |
requestBody={"password":"123","username":"123"}
對應的，響應體日誌切面 LogResponseBodyAdvice 實現如下：
@ControllerAdvice
public class LogResponseBodyAdvice implements ResponseBodyAdvice {
private Logger logger = LoggerFactory.getLogger(LogResponseBodyAdvice.class);
@Override
public boolean supports(MethodParameter returnType, Class converterType) {
return true;
}
@Override
public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType, Class selectedConverterType, ServerHttpRequest request, ServerHttpResponse response) {
logger.debug("uri={} | responseBody={}", request.getURI().getPath(), JSON.toJSONString(body));
return body;
}
}
得到日誌記錄如下：
2017-05-02 22:48:15.520 DEBUG 888 --- [nio-8080-exec-1] c.q.funda.advice.LogResponseBodyAdvice : uri=/sys/user/login |
responseBody={"code":10101,"msg":"手機號格式不合法"}
2. 異常日誌管理
Debug 日誌只適用於開發及測試階段，一般應用部署生產，鑒於日誌裏面的敏感信息過多，往往只會在程序出現異常時輸出明細的日誌信息，在 ExceptionHandler 標註的方法裏面輸入異常日誌無疑是最好的，但擺在面前的一個問題是，如何將 @RequestBody 綁定的 Model 傳遞給異常處理方法？我想到的是通過 ThreadLocal 這個線程本地變量來存儲每一次請求的 Model，這樣就可以貫穿整個請求處理流程，下面使用 ThreadLocal 來協助完成異常日誌的記錄。
在綁定時，將綁定 Model 有存放到 ThreadLocal：
@RestController
@RequestMapping("/sys/user")
public class UserController {
public static final ThreadLocal<Object> MODEL_HOLDER = new ThreadLocal<>();
@InitBinder
public void initBinder(WebDataBinder webDataBinder) {
MODEL_HOLDER.set(webDataBinder.getTarget());
}
}
異常處理時，從 ThreadLocal 中取出變量，並做相應的日誌輸出：
@ControllerAdvice
@ResponseBody
public class ExceptionHandlerAdvice {
private Logger logger = LoggerFactory.getLogger(ExceptionHandlerAdvice.class);
@ExceptionHandler(Exception.class)
public Result handleException(Exception e, HttpServletRequest request) {
logger.error("uri={} | requestBody={}", request.getRequestURI(),
JSON.toJSONString(UserController.MODEL_HOLDER.get()));
return new Result(ResultCode.WEAK_NET_WORK);
}
}
當異常產生時，輸出日誌如下：
2017-05-03 21:46:07.177 ERROR 633 --- [nio-8080-exec-1] c.q.funda.advice.ExceptionHandlerAdvice : uri=/sys/user/login |
requestBody={"password":"123","username":"13632672222"}
註意：當 Mapping 方法中帶有多個參數時，需要將 @RequestBody 綁定的變量當作方法的最後一個參數，否則 ThreadLocal 中的值將會被其它值所替換。如果需要輸出 Mapping 方法中所有參數，可以在 ThreadLocal 裏面存放一個 Map 集合。
項目的 github 地址：https://github.com/qchery/funda
原文地址：http://blog.csdn.net/chinrui/article/details/71056847
SpringBoot實戰 之 接口日誌篇