Dalam praktiknya, sering kali perlu menangani pengecualian secara terpusat di dalam pengontrol atau bahkan seluruh aplikasi. Pada artikel ini, kami akan menganalisis fitur-fitur utama yang disediakan Spring Framework untuk menyelesaikan masalah ini dan, dengan menggunakan contoh sederhana, mari kita lihat bagaimana semuanya bekerja. Siapa yang tertarik dengan topik ini - selamat datang di bawah cut!
Awalnya, sebelum musim semi 3.2, cara utama untuk menangani pengecualian dalam aplikasi yang HandlerExceptionResolver dan @ExceptionHandler penjelasan . Kami akan menganalisisnya lebih detail di bawah, tetapi mereka memiliki kekurangan tertentu. Dimulai dengan versi 3.2, anotasi @ControllerAdvice muncul , yang menghilangkan batasan dari solusi sebelumnya. Dan di Musim Semi 5, kelas ResponseStatusException baru telah ditambahkan yang sangat berguna untuk menangani kesalahan dasar untuk REST API .
Dan sekarang, hal pertama yang pertama, ayo pergi!
Penanganan Pengecualian Pengontrol - @ExceptionHandler
@ExceptionHandler . , , .
:
@RestController
public class Example1Controller {
@GetMapping(value = "/testExceptionHandler", produces = APPLICATION_JSON_VALUE)
public Response testExceptionHandler(@RequestParam(required = false, defaultValue = "false") boolean exception)
throws BusinessException {
if (exception) {
throw new BusinessException("BusinessException in testExceptionHandler");
}
return new Response("OK");
}
@ExceptionHandler(BusinessException.class)
public Response handleException(BusinessException e) {
return new Response(e.getMessage());
}
}testExceptionHandler, BusinessException, — . , , .
handleException . @ExceptionHandler(BusinessException.class), BusinessException. @ExceptionHandler , : @ExceptionHandler({BusinessException.class, ServiceException.class}).
— 200 JSON . , @ResponseStatus, @ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR).
:
:
@ExceptionHandler , . @ExceptionHandler , , , .
HandlerExceptionResolver
HandlerExceptionResolver Spring. HandlerExceptionResolver. , , Spring . :
ExceptionHandlerExceptionResolver — @ExceptionHandler, .
DefaultHandlerExceptionResolver — Spring , :
| Exception | HTTP Status Code |
|---|---|
| BindException | 400 (Bad Request) |
| ConversionNotSupportedException | 500 (Internal Server Error) |
| HttpMediaTypeNotAcceptableException | 406 (Not Acceptable) |
| HttpMediaTypeNotSupportedException | 415 (Unsupported Media Type) |
| HttpMessageNotReadableException | 400 (Bad Request) |
| HttpMessageNotWritableException | 500 (Internal Server Error) |
| HttpRequestMethodNotSupportedException | 405 (Method Not Allowed) |
| MethodArgumentNotValidException | 400 (Bad Request) |
| MissingServletRequestParameterException | 400 (Bad Request) |
| MissingServletRequestPartException | 400 (Bad Request) |
| NoSuchRequestHandlingMethodException | 404 (Not Found) |
| TypeMismatchException | 400 (Bad Request) |
, REST API . . ModelAndView, , .
ResponseStatusExceptionResolver — @ResponseStatus.
ServiceException:
@ResponseStatus(value = HttpStatus.INTERNAL_SERVER_ERROR)
public class ServiceException extends Exception {
public ServiceException(String message) {
super(message);
}
}ServiceException @ResponseStatus value INTERNAL_SERVER_ERROR, - 500.
:
@RestController
public class Example2Controller {
@GetMapping(value = "/testResponseStatusExceptionResolver", produces = APPLICATION_JSON_VALUE)
public Response testResponseStatusExceptionResolver(@RequestParam(required = false, defaultValue = "false") boolean exception)
throws ServiceException {
if (exception) {
throw new ServiceException("ServiceException in testResponseStatusExceptionResolver");
}
return new Response("OK");
}
}GET- exception=true, 500- :
— . , @ResponseStatus .
HandlerExceptionResolver , - JSON XML . , .
:
@Component
public class CustomExceptionResolver extends AbstractHandlerExceptionResolver {
@Override
protected ModelAndView doResolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
ModelAndView modelAndView = new ModelAndView(new MappingJackson2JsonView());
if (ex instanceof CustomException) {
modelAndView.setStatus(HttpStatus.BAD_REQUEST);
modelAndView.addObject("message", "CustomException was handled");
return modelAndView;
}
modelAndView.setStatus(HttpStatus.INTERNAL_SERVER_ERROR);
modelAndView.addObject("message", "Another exception was handled");
return modelAndView;
}
}, . , : , ModelAndView. JSON, .
-, . . , . , — :
@RestController
public class Example3Controller {
@GetMapping(value = "/testCustomExceptionResolver", produces = APPLICATION_JSON_VALUE)
public Response testCustomExceptionResolver(@RequestParam(required = false, defaultValue = "false") boolean exception)
throws CustomException {
if (exception) {
throw new CustomException("CustomException in testCustomExceptionResolver");
}
return new Response("OK");
}
}:
200 JSON .
@ControllerAdvice
— . Spring 3.2 @ControllerAdvice.
:
@ControllerAdvice
public class DefaultAdvice {
@ExceptionHandler(BusinessException.class)
public ResponseEntity<Response> handleException(BusinessException e) {
Response response = new Response(e.getMessage());
return new ResponseEntity<>(response, HttpStatus.OK);
}
} , @ControllerAdvice , .
DefaultAdvice handleException. handleException @ExceptionHandler, , , . BusinessException.
: @ExceptionHandler({BusinessException.class, ServiceException.class}). @ExceptionHandler .
, handleException ResponseEntity Response:
public class Response {
private String message;
public Response() {
}
public Response(String message) {
this.message = message;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
}
, JSON . message HttpStatus.OK, 200.
:
@RestController
public class Example4Controller {
@GetMapping(value = "/testDefaultControllerAdvice", produces = APPLICATION_JSON_VALUE)
public Response testDefaultControllerAdvice(@RequestParam(required = false, defaultValue = "false") boolean exception)
throws BusinessException {
if (exception) {
throw new BusinessException("BusinessException in testDefaultControllerAdvice");
}
return new Response("OK");
}
}, , JSON 200:
?
! :
@ControllerAdvice(annotations = CustomExceptionHandler.class)
public class CustomAdvice {
@ExceptionHandler(BusinessException.class)
public ResponseEntity<Response> handleException(BusinessException e) {
String message = String.format("%s %s", LocalDateTime.now(), e.getMessage());
Response response = new Response(message);
return new ResponseEntity<>(response, HttpStatus.OK);
}
}@ControllerAdvice(annotations = CustomExceptionHandler.class). CustomAdvice , @CustomExceptionHandler.
@CustomExceptionHandler :
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface CustomExceptionHandler {
}:
@RestController
@CustomExceptionHandler
public class Example5Controller {
@GetMapping(value = "/testCustomControllerAdvice", produces = APPLICATION_JSON_VALUE)
public Response testCustomControllerAdvice(@RequestParam(required = false, defaultValue = "false") boolean exception)
throws BusinessException {
if (exception) {
throw new BusinessException("BusinessException in testCustomControllerAdvice");
}
return new Response("OK");
}
}Example5Controller @CustomExceptionHandler, Example4Controller . BusinessException CustomAdvice, DefaultAdvice, .
CustomAdvice — :
. @ControllerAdvice, . .
ResponseStatusException.
ResponseStatusException:
@RestController
public class Example6Controller {
@GetMapping(value = "/testResponseStatusException", produces = APPLICATION_JSON_VALUE)
public Response testResponseStatusException(@RequestParam(required = false, defaultValue = "false") boolean exception) {
if (exception) {
throw new ResponseStatusException(HttpStatus.INTERNAL_SERVER_ERROR, "ResponseStatusException in testResponseStatusException");
}
return new Response("OK");
}
}ResponseStatusException , , . @ResponseStatus — -. , .
:
Ringkasan : kita telah melihat berbagai cara menangani pengecualian, yang masing-masing memiliki karakteristiknya sendiri. Dalam aplikasi besar, Anda dapat menemukan beberapa pendekatan sekaligus, tetapi Anda harus sangat berhati-hati dan mencoba untuk tidak membuat logika penanganan kesalahan menjadi terlalu rumit. Jika tidak, ternyata beberapa pengecualian akan ditangani di penangan yang salah dan responsnya akan berbeda dari yang diharapkan. Misalnya, jika aplikasi memiliki beberapa penasihat, maka saat membuat yang baru, Anda perlu memastikan bahwa itu tidak merusak urutan penanganan pengecualian yang ada dari pengontrol lama.
Jadi berhati-hatilah dan semuanya akan bekerja dengan baik!