How to get error text in controller from BindingResult

Question

I have an controller that returns JSON. It takes a form, which validates itself via spring annotations. I can get FieldError list from BindingResult, but they don't contain the text that a JSP would display in the tag. How can I get the error text to send back in JSON?

@RequestMapping(method = RequestMethod.POST) public @ResponseBody JSONResponse submit(@Valid AnswerForm answerForm, BindingResult result, Model model, HttpServletRequest request, HttpServletResponse response) {      if (result.hasErrors()) {         response.setStatus(HttpServletResponse.SC_BAD_REQUEST);         JSONResponse r = new JSONResponse();         r.setStatus(JSONResponseStatus.ERROR);         //HOW DO I GET ERROR MESSAGES OUT OF BindingResult???      } else {         JSONResponse r = new JSONResponse();         r.setStatus(JSONResponseStatus.OK);         return r;     }  } 

JSONREsponse class is just a POJO

public class JSONResponse implements Serializable {     private JSONResponseStatus status;     private String error;     private Map<String,String> errors;     private Map<String,Object> data;  ...getters and setters... } 

Calling BindingResult.getAllErrors() returns an array of FieldError objects, but it doesn't have the actual errors.

Answer 1

Disclaimer: I still do not use Spring-MVC 3.0

But i think the same approach used by Spring 2.5 can fullfil your needs

for (Object object : bindingResult.getAllErrors()) {     if(object instanceof FieldError) {         FieldError fieldError = (FieldError) object;          System.out.println(fieldError.getCode());     }      if(object instanceof ObjectError) {         ObjectError objectError = (ObjectError) object;          System.out.println(objectError.getCode());     } } 

I hope it can be useful to you

UPDATE

If you want to get the message provided by your resource bundle, you need a registered messageSource instance (It must be called messageSource)

<bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource">     <property name="basenames" value="ValidationMessages"/> </bean> 

Inject your MessageSource instance inside your View

@Autowired private MessageSource messageSource; 

And to get your message, do as follows

for (Object object : bindingResult.getAllErrors()) {     if(object instanceof FieldError) {         FieldError fieldError = (FieldError) object;          /**           * Use null as second parameter if you do not use i18n (internationalization)           */          String message = messageSource.getMessage(fieldError, null);     } } 

Your Validator should looks like

/**   * Use null as fourth parameter if you do not want a default message   */ errors.rejectValue("<FIELD_NAME_GOES_HERE>", "answerform.questionId.invalid", new Object [] {"123"}, null); 

Answer 2

I met this problem recently, and found an easier way (maybe it's the support of Spring 3)

    List<FieldError> errors = bindingResult.getFieldErrors();     for (FieldError error : errors ) {         System.out.println (error.getObjectName() + " - " + error.getDefaultMessage());     } 

There's no need to change/add the message source.