java - SpringBoot doesn't handle org.hibernate.exception.ConstraintViolationException

Question

I have defined a pattern for validating email in my Entity class. In my validation exception handler class, I have added handler for ConstraintViolationException. My application utilize SpringBoot 1.4.5.

Profile.java

@Entity
@EntityListeners(AuditingEntityListener.class)
@Table(name = "profile")
public class Profile extends AuditableEntity {

  private static final long serialVersionUID = 8744243251433626827L;

  @Column(name = "email", nullable = true, length = 250)
  @NotNull
  @Pattern(regexp = "^([^ @])+@([^ \.@]+\.)+([^ \.@])+$")
  @Size(max = 250)
  private String email;
....
}

ValidationExceptionHandler.java

@ControllerAdvice
public class ValidationExceptionHandler extends ResponseEntityExceptionHandler {

  private MessageSource messageSource;

  @Autowired
  public ValidationExceptionHandler(MessageSource messageSource) {
    this.messageSource = messageSource;
  }

  @ExceptionHandler(ConstraintViolationException.class)
  public ResponseEntity<Object> handleConstraintViolation(ConstraintViolationException ex,
  WebRequest request) {
    List<String> errors = new ArrayList<String>();
    ....
    }
} 

When I run my code and pass invalid email address, I get the following exception. The code in handleConstraintViolation is never executed. The http status returned in the exception is 500, but I want to return 400. Any idea how I can achieve that?

2017-07-12 22:15:07.078 ERROR 55627 --- [nio-9000-exec-2] o.h.c.s.u.c.UserProfileController        : Validation failed for classes [org.xxxx.common.service.user.domain.Profile] during persist time for groups [javax.validation.groups.Default, ]
List of constraint violations:[
ConstraintViolationImpl{interpolatedMessage='must match "^([^ @])+@([^ .@]+.)+([^ .@])+$"', propertyPath=email, rootBeanClass=class org.xxxx.common.service.user.domain.Profile, messageTemplate='{javax.validation.constraints.Pattern.message}'}]

javax.validation.ConstraintViolationException: Validation failed for classes [org.xxxx.common.service.user.domain.Profile] during persist time for groups [javax.validation.groups.Default, ]
List of constraint violations:[
ConstraintViolationImpl{interpolatedMessage='must match "^([^ @])+@([^ .@]+.)+([^ .@])+$"', propertyPath=email, rootBeanClass=class org.xxxx.common.service.user.domain.Profile, messageTemplate='{javax.validation.constraints.Pattern.message}'}]

at  org.hibernate.cfg.beanvalidation.BeanValidationEventListener.validate(BeanValidationEventListener.java:138)

at org.hibernate.cfg.beanvalidation.BeanValidationEventListener.onPreInsert(BeanValidationEventListener.java:78)    

Answer 1

You cannot catch ConstraintViolationException.class because it's not propagated to that layer of your code, it's caught by the lower layers, wrapped and rethrown under another type. So that the exception that hits your web layer is not a ConstraintViolationException.

In my case, it's a TransactionSystemException. I'm using @Transactional annotations from Spring with the JpaTransactionManager. The EntityManager throws a rollback exception when somethings goes wrong in the transaction, which is converted to a TransactionSystemException by the JpaTransactionManager.

So you could do something like this:

@ExceptionHandler({ TransactionSystemException.class })
public ResponseEntity<RestResponseErrorMessage> handleConstraintViolation(Exception ex, WebRequest request) {
    Throwable cause = ((TransactionSystemException) ex).getRootCause();
    if (cause instanceof ConstraintViolationException) {
        Set<ConstraintViolation<?>> constraintViolations = ((ConstraintViolationException) cause).getConstraintViolations();
        // do something here
    }
}