在 Spring 中为 MethodArgumentNotValidException 添加参数到 @ExceptionHandler

Question

I have a Spring controller that validates incoming requests with hibernate validator.

When the request is invalid, MethodArgumentNotValidException is thrown by the validator. Would it be possible to add additional class as an argument to handler method for the exception?

This is what i have:

@RequestMapping(value = "/...", method = RequestMethod.POST)
@ResponseBody
public Response handleCustomObject(@Valid @RequestBody CustomObject obj) {
  //..
}


@ExceptionHandler(MethodArgumentNotValidException.class)
@ResponseBody
public Response handleInvalidRequest(MethodArgumentNotValidException e) {

    return getMissingMandatoryParametersResponse(e);

    }
}

And i would need something like example bellow, however this doesn't work:

@ExceptionHandler(MethodArgumentNotValidException.class)
@ResponseBody
public Response handleInvalidRequest(MethodArgumentNotValidException e, CustomObject obj) {

 // do something with CustomObject
}

Answer 1

If you want to do something with the object which failed the validation in the exception handler, you can retrieve it from BindingResult like so:

@ExceptionHandler(MethodArgumentNotValidException.class)
@ResponseBody
public Response handleInvalidRequest(MethodArgumentNotValidException e) {
    CustomObject ce = (CustomObject) e.getBindingResult().getTarget();
    // do something with CustomObject
}

You can also take a look at Spring JavaDoc for @ExceptionHandler annotation to see the list of supported exception handler method argument types:

Handler methods which are annotated with this annotation are allowed to have very flexible signatures. They may have arguments of the following types, in arbitrary order:

• An exception argument: declared as a general Exception or as a more specific exception. This also serves as a mapping hint if the annotation itself does not narrow the exception types through its value().
• Request and/or response objects (Servlet API or Portlet API). You may choose any specific request/response type, eg ServletRequest / HttpServletRequest or PortletRequest / ActionRequest / RenderRequest. Note that in the Portlet case, an explicitly declared action/render argument is also used for mapping specific request types onto a handler method (in case of no other information given that differentiates between action and render requests).
• Session object (Servlet API or Portlet API): either HttpSession or PortletSession. An argument of this type will enforce the presence of a corresponding session. As a consequence, such an argument will never be null. Note that session access may not be thread-safe, in particular in a Servlet environment: Consider switching the "synchronizeOnSession" flag to "true" if multiple requests are allowed to access a session concurrently.
• WebRequest or NativeWebRequest. Allows for generic request parameter access as well as request/session attribute access, without ties to the native Servlet/Portlet API.
• Locale for the current request locale (determined by the most specific locale resolver available, ie the configured LocaleResolver in a Servlet environment and the portal locale in a Portlet environment).
• InputStream / Reader for access to the request's content. This will be the raw InputStream/Reader as exposed by the Servlet/Portlet API.
• OutputStream / Writer for generating the response's content. This will be the raw OutputStream/Writer as exposed by the Servlet/Portlet API.