spring 无法读取 HTTP 消息：org.springframework.http.converter.HttpMessageNotReadableException：缺少所需的请求正文
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Failed to read HTTP message: org.springframework.http.converter.HttpMessageNotReadableException: Required request body is missing
提问by Hadi Rasouli
I have and Interceptor and for some reasons i have to read POSTED date included in HttpServletRequestlike this:
我有拦截器，出于某些原因，我必须HttpServletRequest像这样阅读 POSTED 日期：
InputStream inputStream = request.getInputStream();
if (inputStream != null) {
bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
char[] charBuffer = new char[128];
int bytesRead = -1;
while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
stringBuilder.append(charBuffer, 0, bytesRead);
}
} else {
stringBuilder.append("");
}
after this action i get 400 bad request for ajax
Failed to read HTTP message: org.springframework.http.converter.HttpMessageNotReadableException: Required request body is missing
执行此操作后，我收到 400 个对 ajax 的错误请求，无法读取 HTTP 消息： org.springframework.http.converter.HttpMessageNotReadableException: Required request body is missing
回答by Hadi Rasouli
Spring provides a class called ContentCachingRequestWrapperwhich extends HttpServletRequestWrapper. This class caches all content read from
the getInputStream()and getReader()and allows this content to be retrieved via a getContentAsByteArray(). So we can retrieve InputStreammultiple times for this purpose. This ability provided by method blow in ContentCachingRequestWrapper:
Spring 提供了一个名为ContentCachingRequestWrapperextends的类HttpServletRequestWrapper。此类缓存从getInputStream()和读取的所有内容，getReader()并允许通过getContentAsByteArray(). 因此，我们可以InputStream为此目的多次检索。这种能力由方法吹入提供ContentCachingRequestWrapper：
@Override
public ServletInputStream getInputStream() throws IOException {
if (this.inputStream == null) {
this.inputStream = new ContentCachingInputStream(getRequest().getInputStream());
}
return this.inputStream;
}
This class fix character encoding issues for UTF-8with method below:
此类UTF-8使用以下方法修复字符编码问题：
@Override
public String getCharacterEncoding() {
String enc = super.getCharacterEncoding();
return (enc != null ? enc : WebUtils.DEFAULT_CHARACTER_ENCODING);
}
Hereis full detail in ContentCachingRequestWrapper.
这里是完整的细节ContentCachingRequestWrapper。
回答by Ali Dehghani
I guess you have a method handler like following:
我猜你有一个像下面这样的方法处理程序：
@RequestMapping(value = "/somewhere", method = POST)
public SomeResponse someHandler(@RequestBody String body, ...) { ... }
And you read the HttpServletRequest's InputStreamin your interceptor. Since you can read the InputStreamonly once, when spring tries to read the InputStreamin order to populate the @RequestBodymethod parameter, it fails and complains with HttpMessageNotReadableException.
并且您在拦截器中读取了HttpServletRequest's InputStream。由于您只能读取InputStream一次，因此当 spring 尝试读取InputStream以填充@RequestBody方法参数时，它会失败并以HttpMessageNotReadableException.
If you seriously need to read the request body multiple times, you should add a filter and decorate the HttpServletRequestin order to add a Multiple Readfeature. For more information you can read this answer.
如果你真的需要多次读取请求体，你应该添加一个过滤器并装饰HttpServletRequest以添加一个Multiple Read特性。有关更多信息，您可以阅读此答案。
