Multipart File Upload:Size exceed exception in spring boot return JSON error message

Question

As I have set maximum file upload limit,I am getting

org.apache.tomcat.util.http.fileupload.FileUploadBase$FileSizeLimitExceededException: The field file exceeds its maximum permitted size of 2097152 bytes 

error while uploading file.It is giving 500 error to my api,I should I handle this error and return response in JSON format not an errorpage as provided in ErrorController

I want to catch that exception and give JSON response not ErrorPage.

@RequestMapping(value="/save",method=RequestMethod.POST)
    public ResponseDTO<String> save(@ModelAttribute @Valid FileUploadSingleDTO fileUploadSingleDTO,BindingResult bindingResult)throws MaxUploadSizeExceededException
    {
        ResponseDTO<String> result=documentDetailsService.saveDocumentSyn(fileUploadSingleDTO, bindingResult);

        return result;

    }

DTO that accepts document as follows

public class FileUploadSingleDTO {
@NotNull
    private Integer documentName;

    private Integer documentVersion;

    @NotNull
    private MultipartFile file;
}

Solution 1

As par I know you can handle the multipart file exception by using this.

@ControllerAdvice
public class MyErrorController extends ResponseEntityExceptionHandler {

Logger logger = org.slf4j.LoggerFactory.getLogger(getClass());

@ExceptionHandler(MultipartException.class)
@ResponseBody
String handleFileException(HttpServletRequest request, Throwable ex) {
    //return your json insted this string.
    return "File upload error";
  }
}

Solution 2

Add a special exception handler into your Controller:

@ExceptionHandler(FileSizeLimitExceededException.class)
public YourReturnType uploadedAFileTooLarge(FileSizeLimitExceededException e) {
    /*...*/
}

(If this does not work, you have to enable exception handling in your configuration. Normally Spring does this by default.)

Comments

[Srinivas Rampelli]

After digging into source code, I found that CommonsMultipartResolver is handling the FileSizeLimitExceededException exception and throwing throw new MultipartException("Could not parse multipart servlet request", ex); here ex is the FileSizeLimitExceededException, which is actually thrown by commons.fileupload.FileuploadBase class. So you cannot handle the FileSizeLimitExceededException. Use generic implementation file upload errors using MultipartException.

[quintin]

@RampelliSrinivas it will be very help full if you can explain the comment you wrote above a bit.