spring请求参数绑定错误

Question

@RequestMapping("/query")
@ResponseBody
public ResponseEntity<Content> getByQuery(HttpServletRequest request, ContentQuery query) {
    // Handle request.
}

This code is going to function as an http wrapper of the ContentQuery object so that i can query content with http-requests from javascript. The automatic binding in Spring binds request parameters to the ContentQuery object.

The problem is that if someone puts an unknown parameter key in the request, the ContentQuery object is stil instantiated, and i don't know how to check if i get unexpected params.

Is there any way to handle this?

Answer 1

then write your own validator and run it in your controller - docs.spring.io/spring/docs/current/spring-framework-reference/… . Then you can return ResponseEntity with any status you want – freakman

Thank you for the hint. Haven't used the Validator interface before, but it looks like a clean solution.

Controller:

@Autowired
private ContentQueryValidator validator;

@RequestMapping("/query")
@ResponseBody
public ResponseEntity<List<Content>> getByQuery(
        HttpServletRequest request, ContentQuery query, BindingResult result) {
    validator.validate(query, result);
    if(result.hasErrors()){
        return new ResponseEntity<>(HttpStatus.BAD_REQUEST);
    }

    // No errors. Fetch content from service using query object.
}

And the validator:

@Component
public class ContentQueryValidator implements Validator{
    @Override
    public boolean supports(Class<?> aClass) {
        return ContentQuery.class.equals(aClass);
    }

    @Override
    public void validate(Object obj, Errors errors) {
        ContentQuery query = (ContentQuery) obj;

        List<Integer> contentTemplate = query.getContentTemplate();
        List<Integer> displayTemplate = query.getDisplayTemplate();

        if(contentTemplate == null && displayTemplate == null){
            errors.reject("No query provided");
        }
        // More validation here..
    }
}