Problems about comsuming request body for multiple times

I'm a new javaer. Recently I'm working on a new springboot project, and I want to print request body before it enter mvc controller. (To be exact, I want to print request body of post request with contentType:"application/json")

I use a requestWrapper as below.

public class MyRequestWrapper extends HttpServletRequestWrapper {
    private byte[] cachedBody = new byte[]{};
    private InputStream input = null;

    public MyRequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        if (request.getContentType() != null && (request.getContentType().contains("multipart/") ||
                request.getContentType().contains("/x-www-form-urlencoded"))) {
            cachedBody = new byte[]{};
            input = request.getInputStream();
        } else {
            cachedBody = StreamUtils.copyToByteArray(request.getInputStream());
            input = new ByteArrayInputStream(cachedBody);
        }
    }

    @Override
    public ServletInputStream getInputStream() {
        return new ServletInputStream() {
            @Override
            public int read() throws IOException {
                return input.read();
            }
        }
    }

    public String getBody() {
        return new String(cachedBody);
    }

Then, I use a filter to print the request content.

@WebFilter(filterName = "RequestResponseFilter", urlPatterns = "/*", asyncSupported = true)
public class RequestResponseFilter implements Filter {

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {

        MyRequestWrapper requestWrapper = (MyRequestWrapper) request;
        ......
        System.out.println(requestWrapper.getBody());
        ......
        chain.doFilter(requestWrapper, response);
    }
}

Below is my controller.

@PostMapping(value="/test")
public ResponseData<String> test(
        @RequestParam("id") String id,
        @RequestParam("value") String value) {
    ResponseData<String> result = new ResponseData<>();
    result.setData(id + value);
    result.setCode(Constants.CODE_SUCCESS);
    return result;
}

However, when I use postman to test my code, it didn't work well. If I use post method and pass param with content-type:"application/x-www-form-urlencoded", it throws "org.springframework.web.bind.MissingServletRequestParameterException".

What confuse me is that, if I pass param with content-type:"multipart/form-data", it work well.

Besides, I have tried CachedBodyHttpServletRequest which provided by spring. But it couldn't get request content until the request enter controller.

Why the mvc controller failed to get param with annotation @RequestParam? And how can I fix it?

u can get param & body like this

public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
    // param
    request.getParameterMap().forEach((k, v) -> System.out.println(k + " : " + v[0]));
    // body
    byte[] array = StreamUtils.copyToByteArray(request.getInputStream());
    System.out.println(new String(array, StandardCharsets.UTF_8));
}

but if u upload file with multipart/form-data then file content can't cast to String, u need tools to resolve it, something like this

if (contentType.startsWith("multipart/form-data")) {
    StandardServletMultipartResolver resolver = new StandardServletMultipartResolver();
    StandardMultipartHttpServletRequest req = (StandardMultipartHttpServletRequest)resolver.resolveMultipart((HttpServletRequest) request);
    System.out.println(req.getMultiFileMap());
    System.out.println(req.getParameterMap());
}

You can read article here: Link

But with multipart/form-data, change class to extend below:
public class CachedBodyHttpServletFormRequest extends StandardMultipartHttpServletRequest {}