How to make custom exception handlers working properly

Question

I want to use custom exception handlers for my application. But, it is not working properly.

Here is my code

AuthenticationFilter.java

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {

    if (!bAuthorize) {
        chain.doFilter(request, response);
        return;
    }

    HttpServletRequest req = (HttpServletRequest) request;

    String namespace = getPathParamFromRequest(req, NAMESPACE_PATH_PREFIX);
    String userId =  getPathParamFromRequest(req, USER_PATH_PREFIX);


    AuthContext auth = null;
    RequestPathContext rpc = pathsList.getMatchingContext(req.getRequestURI(), HttpMethod.valueOf(req.getMethod()));
    if (rpc != null)
        auth = rpc.getAuthContext();

    if (auth != null) {
        // Authentication process
    } else {
        throw new UnauthorizedException();
    }
}

ApplicationExceptionHandler.java

public class ApplicationExceptionHandler {
  @ExceptionHandler(UnauthorizedException.class)
  public ResponseEntity<ErrorEntity> applicationxception(final UnauthorizedException e) {
    ErrorEntity errorEntity = new ErrorEntity(e.getNumericErrorCode(), e.getErrorCode(), e.getErrorMessage());
    return new ResponseEntity<>(errorEntity, HttpStatus.valueOf(e.getHttpStatus()));
  }
}

AuthFilterRegistration.java

@Configuration
public class AuthFilterRegistration {

  @Autowired
  private ApplicationContext context;

  @Bean
  public FilterRegistrationBean<AuthenticationFilter> loggingFilter() {
    FilterRegistrationBean<AuthenticationFilter> registrationBean
            = new FilterRegistrationBean<>();

    registrationBean.setFilter(context.getBean(AuthenticationFilter.class));
    registrationBean.addUrlPatterns( "/public/*");

    return registrationBean;
  }

  @Bean
  public AuthenticationFilter getAuthFilter() {
    return new AuthenticationFilter();
  }

  @Bean
  public ApplicationExceptionHandler getErrorHandler() {
    return new ApplicationExceptionHandler();
  }

}

ErrorEntity.java

public class ErrorEntity extends BaseErrorEntity {

  String errorMessage;

  Map<String, String> messageVariables;

  public ErrorEntity() {
  }

  public ErrorEntity(int numericErrorCode, String errorCode, String errorMessage) {
    this(numericErrorCode, errorCode, errorMessage, null);
  }

  public ErrorEntity(int numericErrorCode, String errorCode, String errorMessage, Map<String, String> messageVariables) {
    this.numericErrorCode = numericErrorCode;
    this.errorCode = errorCode;
    this.errorMessage = errorMessage;
    this.messageVariables = messageVariables;
  }

}

Using those code, I want to have an exception error like this

{
  "numericErrorCode": 2001,
  "errorCode": "errors.net.myproject.platform.unauthorized",
  "errorMessage": "unauthorized"
}

which is the instance of ErrorEntity, but I got this output

{
  "timestamp": "2019-02-01T04:41:14.337+0000",
  "status": 500,
  "error": "Internal Server Error",
  "message": "unauthorized",
}

From the example it is clear that I cannot override the default Java exception completely. Only the message part that is altered successfully. Do I miss something here?

if I'm not mistaken, if you create your ExceptionHandlers with methods like that, they only work for the Exceptions thrown in the class in which they are defined — Stultuske, Feb 01 '19 at 07:04
@Stultuske So, do you mean that the exception should also be defined in `AuthenticationFilter` class? — Rafi Ramadhan, Feb 01 '19 at 07:10
No, I mean that if you want to implement an @ExceptionHandler the way you do, you should have it in the class where the Exception is thrown. But I don't see any methods that actually throw those Exceptions — Stultuske, Feb 01 '19 at 07:12
I think I throw an `UnauthorizedException` inside the else block in `AuthenticationFilter` class. Or am I doing it wrong? — Rafi Ramadhan, Feb 01 '19 at 07:18
@RafiRamadhan yet your method signature doesn't suggest your method can throw that Exception? — Stultuske, Feb 01 '19 at 07:19
@RafiRamadhan did you used `@ControllerAdvice` annotation on your class? and this `@ResponseBody` on your handler method????? — Muhammad Waqas, Feb 01 '19 at 07:23
@MuhammadWaqas Yes, I use `@ControllerAdvice`in `ApplicationExceptionHandler`class. And where should I put the `@ResponseBody` annotation? — Rafi Ramadhan, Feb 01 '19 at 07:26
@Stultuske Do you mean the signature should be like this? `public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws UnauthorizedException`? — Rafi Ramadhan, Feb 01 '19 at 07:30
Yes. And, as I said, that way of Error Handling only works for the Controller you've written the error handling method in. Check this link: https://www.baeldung.com/exception-handling-for-rest-with-spring — Stultuske, Feb 01 '19 at 07:45

Muhammad Waqas · Answer 1 · 2019-02-01T07:53:24.747


import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;

@ControllerAdvice
public class ApplicationExceptionHandler extends ResponseEntityExceptionHandler {

@ResponseBody
@ExceptionHandler(UnauthorizedException.class)
public ResponseEntity<ErrorEntity> applicationxception(final UnauthorizedException e) {
    ErrorEntity errorEntity = new ErrorEntity(e.getNumericErrorCode(), e.getErrorCode(), e.getErrorMessage());
    return new ResponseEntity<>(errorEntity, HttpStatus.valueOf(e.getHttpStatus()));
}

@ResponseBody
@ExceptionHandler(RetrievedProfileException.class)
public ResponseEntity<ErrorEntity> applicationexception(final RetrievedProfileException e) {
    ErrorEntity errorEntity = new ErrorEntity(e.getNumericErrorCode(), e.getErrorCode(), e.getErrorMessage());
    return new ResponseEntity<>(errorEntity, HttpStatus.valueOf(e.getHttpStatus()));
}

I just extend this class org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler because its pre- requsite

Secondly i used @ControllerAdvice

and lastly i used @ResponseBody

Use Exception Handler this way plus you should override the exception in this way.

I just extend this class `org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler` because its pre- requsite Secondly i used [`@ControllerAdvice`](https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/web/bind/annotation/ControllerAdvice.html) and lastly i used [@ResponseBody](https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/web/bind/annotation/ResponseBody.html) — Muhammad Waqas, Feb 01 '19 at 07:30
[Handle spring security authentication exceptions with @ExceptionHandler](https://stackoverflow.com/questions/19767267/handle-spring-security-authentication-exceptions-with-exceptionhandler) Check this post. Maybe this will help you. @RafiRamadhan — Muhammad Waqas, Feb 01 '19 at 07:42

How to make custom exception handlers working properly

1 Answers1