缺少请求正文的 Spring Boot POST 请求？

Question

I have a very simple HTML form page (which is a part of Spring Boot web application in src/main/resources/public/web.html) to post a String from a textarea to a Spring Boot web application version 1.5.2.

<form action="" method="post">
<textarea cols="128" rows="40" name="query"></textarea>
<input value="Send" type="submit">
</form>

And the SpringBoot class to handle the POST request:

@RestController
public class QueryController {
    @RequestMapping(value = "/handle", method = RequestMethod.POST)
    protected void handlePost(@RequestBody String postBody) throws Exception {
       // Get query from postBody here
    }
}

It works with small String from textarea in client. However, when the String is big (eg: with HTTP request header: Content-Length:3789333 (3 MB)). Spring Boot throws an exception like this:

org.springframework.http.converter.HttpMessageNotReadableException: Required request body is missing: protected void QueryController.handlePost(java.lang.String) throws java.lang.Exception
at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.readWithMessageConverters(RequestResponseBodyMethodProcessor.java:154)
at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.resolveArgument(RequestResponseBodyMethodProcessor.java:128)
at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:121)

I'm not sure what causes this problem, I'm running the web application with embedded Tomcat from Spring Boot.

Answer 1

我不确定，但这可能是由于缺少内容编码造成的吗？

Answer 2

The problem is @RequestBody cannot get value for the big query. However, get request body from HttpServletRequest it can get value

 protected void handlePost(HttpServletRequest httpServletRequest) throws Exception {
    String postBody = this.getPOSTRequestBody(httpServletRequest); 

 }

Answer 3

Update your contoller to following:

@RestController
public class QueryController {
    @RequestMapping(value = "/handle", method = RequestMethod.POST)
    protected void handlePost(@RequestParam(value="query",required=false) String query) throws Exception {
       // Your code goes here
    }
}

If you do not pass paramater you will get org.springframework.web.bind.MissingServletRequestParameterException: Required String parameter 'query' is not present . If paramater not required you can add required=false to RequestParam . By default required=true for RequestParam.

It depends to your server. I hope your are using Tomcat . By default server has maxPostSize . The following is for Tomcat

<Connector port="8080" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8443"
               maxPostSize="6291456" />

maxPostSize is 6MB in my preceding code.