Custom Exception in Sprin Boot

Question

I have written the below Custom Error Handler in SPRING BOOT

@RestControllerAdvice 
public class CustomGlobalExceptionHandler extends ResponseEntityExceptionHandler {

    @ExceptionHandler
   // @ResponseBody
    public ResponseEntity<CustomErrorResponse> customHandleNotFound(Exception ex, WebRequest request) {

        CustomErrorResponse errors = new CustomErrorResponse();
        errors.setTimestamp(LocalDateTime.now());
        errors.setError(ex.getMessage());
        errors.setStatus(HttpStatus.CONFLICT.value());
        errors.setErrorMsg(errors.getErrorMsg());

        return  ResponseEntity.ok(errors);

    }

Below is my code Controller method

@RestController
@RequestMapping(value="/api")
public class AppController {




   @Autowired
    private UserRepository userRepository;



      @RequestMapping(value="/home/{id1}" ,method=RequestMethod.PUT)
     @ResponseBody
      public String home(@PathVariable("id1") Long idValue,    @RequestBody @Valid Student s)
    {

         System.out.println( " idValue is  "  + idValue);

        System.out.println( " Student -->" + s.getName()  + " -- "  + s.getId());


      return    "job done";

    }



      @RequestMapping("/foos")
    //  @ResponseBody
      public String getFoos(@RequestParam(value="t1",required=true)  String id)  {

          int i =1/0;

          System.out.println(" id is " + i++);
            return "ID: " + id + "  status: Success";
      }

The exception handler is working fine for the method getFoos() when it encounters 1/0 I get the output in POSTMAN as which is as expected

{
    "timestamp": "2019-08-04 11:24:22",
    "status": 409,
    "error": "/ by zero",
    "errorMsg": "ERROR-msg"
}

But in my home() method I deliberately made Student object as invalid and I get no error message in POSTMAN but just in the eclipse console. Why?

I get this message.So how do I kick in CustomGlobalExceptionHandler when the Student object is invalid

2019-08-04 23:25:57.551 WARN 9652 --- [nio-8080-exec-6] .m.m.a.ExceptionHandlerExceptionResolver : Resolved [org.springframework.http.converter.HttpMessageNotReadableException: Required request body is missing: public java.lang.String com.example.hibernatemapping.controller.AppController.home(java.lang.Long,com.example.hibernatemapping.domain.Student)]

Add `@ExceptionHandler({HttpMessageNotReadableException.class, Exception.class})` — Jonathan JOhx, Aug 04 '19 at 18:42
Ambiguous @ExceptionHandler method mapped for [class org.springframework.http.converter.HttpMessageNotReadableException]: {public org.springframework.http.ResponseEntity com.example.hibernatemapping.exception.CustomGlobalExceptionHandler.customHandleNotFound(java.lang.Exception,org.springframework.web.context.request.WebRequest), public final org.springframework.http.ResponseEntity org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler.handleException(java.lang.Exception,org.springframework.web.context.request.WebRequest) — Raj R, Aug 04 '19 at 18:50
Okay if you create a new method for that handler on that exception? `@ExceptionHandler(HttpMessageNotReadableException.class)` looks like it is an exception in RunTime is not caught by the handlers, so please do that and let me how it goes. — Jonathan JOhx, Aug 04 '19 at 18:59
so you have @Valid Student s and the ExceptionHandler ? Wich should be triggered ? Try to remove the Valid Student s from your home() method — AchillesVan, Aug 04 '19 at 19:04

score 0 · Answer 1 · answered Aug 04 '19 at 18:10

Well, there are many things to say.

First, exception handlers take an exception class as parameter, which allow you to return other errors following the exception class you throw in a controller method.

The one you wrote catch all exceptions and return the same error model, which is not a right idea. The right way to do is to write an abstract class AbstractMyAppException that extends Exception, and then implement a new class that extends of it for every error case you have.

Then, add two @ExceptionHandler :

One bind on the AbstractMyAppException class that return all errors that your app generate
One bind on the Exception class that return all other errors that should not happen.

For your case, it seems that you are using Spring Validation (you are using @Valid annotation). So make sure that you have followed this tutorial.

Then, your question is about catching validation errors to show a custom message if a student is invalid. Then check this thread.

it doesn't answer my question.More over this answer confused me — Raj R, Aug 04 '19 at 18:17
Then sorry, but your question is not very clear ... Could you specify what do you want to know exactly ? — Jordan Lefébure, Aug 04 '19 at 18:19
I want the home() to return the error is the same format as ` { "timestamp": "2019-08-04 11:24:22", "status": 409, "error": "/ by zero", "errorMsg": "ERROR-msg" }` This is my CustomErrorResponse class fields — Raj R, Aug 04 '19 at 18:21

score 0 · Answer 2 · answered Aug 04 '19 at 19:06

I solved it by adding the below in my ControllerAdviceI will just change the code to map error to my custom Pojo class CustomErrorResponse

    @Override
    protected ResponseEntity<Object> handleMethodArgumentNotValid(MethodArgumentNotValidException ex,
                                                                  HttpHeaders headers,
                                                                  HttpStatus status, WebRequest request) {

        Map<String, Object> body = new LinkedHashMap<>();
        body.put("timestamp", new Date());
        body.put("status", status.value());

        //Get all errors
        List<String> errors = ex.getBindingResult()
                .getFieldErrors()
                .stream()
                .map(x -> x.getDefaultMessage())
                .collect(Collectors.toList());

        body.put("errors", errors);

         System.out.println( " erro here ");
        return new ResponseEntity<>(body, headers, status);


}

Custom Exception in Sprin Boot

2 Answers2