How to get the request body data inside ExceptionHandler class in springboot(REST)

Question

I have a class annotated with @ControllerAdvice and methods annotated with @ExceptionHandler to handle exceptions thrown by the service code. When handling these exceptions, I would like to get the @RequestBody that was part of the request POST operations.

I tried by creating POJO class for the request sent and tried to retrieve inside exception handler class but it returns null.

Followed the same solution given in this query~ How to get the @RequestBody in an @ExceptionHandler (Spring REST)

It doesn't work.

I also tried with httpServertRequest, even that return null for the request data.

I want to get the request body of the api inside ExceptionHandler method. Based on the request body data I have to return the error response.

I also want the query param data to be used inside ExceptionHandler method.

Please provide with a solution. Thank you.

Answer 1

The Stream of Request Body only read once, so you can't retrieve it for the second time inside ControllerAdvice, thus cache the request body with ContentCachingRequestWrapper first. Create a new Spring component like this:

@Component
public class FilterConfig extends GenericFilterBean{
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException{
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        ContentCachingRequestWrapper wrapper = new ContentCachingRequestWrapper(request);
        filterChain.doFilter(wrapper, servletResponse);
    }
}

then in @ControllerAdvice make your @ExceptionHandler accept ContentCachingRequestWrapper as parameter.

    @ExceptionHandler(Exception.class)
    public ResponseEntity<Object> handleDefaultException(Exception ex, ContentCachingRequestWrapper request){
        String reqBody = "your request body is " + new String(request.getContentAsByteArray(), StandardCharsets.UTF_8);
        // then do another thing you wanted for exception handling
    }