Developers face many different types of errors when building applications. These errors can be caused by user input, by problems with the code, or by issues with the server or database.
In this article, we'll take a look at how to handle errors in Spring Boot. We'll start with a brief overview of the different types of errors that can occur, and then we'll discuss how to handle them using the @ControllerAdvice annotation.
There are three main types of errors that can occur when building a Spring Boot application:
Validation errors: These occur when the user input does not match the expected format. For example, if a user tries to submit a form with an invalid email address, a validation error will occur.
Binding errors: These occur when the data binding process fails. This can happen if the user input is in the wrong format, or if there is a type mismatch between the input and the target object.
Other errors: These include all other types of errors, such as database errors, server errors, and so on.
In Spring Boot, errors can be handled using the @ControllerAdvice annotation. This annotation can be used to define a global error handler for all controllers.
The @ControllerAdvice annotation can be used to handle both validation and binding errors. To handle other types of errors, you can use the @ExceptionHandler annotation.
Validation errors can be handled using the @ControllerAdvice annotation. In the following example, we're using the @ControllerAdvice annotation to handle validation errors:
@ControllerAdvice
public class ValidationErrorHandler {
@InitBinder
public void initBinder(WebDataBinder binder) {
binder.addValidators(new UserValidator());
}
@ExceptionHandler(MethodArgumentNotValidException.class)
public ResponseEntity<?> handleValidationErrors(MethodArgumentNotValidException ex) {
// ...
}
}
In the example above, we're using the @InitBinder annotation to register a validator for the User class. We're also using the @ExceptionHandler annotation to handle validation errors.
Binding errors can be handled using the @ControllerAdvice annotation. In the following example, we're using the @ControllerAdvice annotation to handle binding errors:
@ControllerAdvice
public class BindingErrorHandler {
@ExceptionHandler(BindException.class)
public ResponseEntity<?> handleBindingErrors(BindException ex) {
// ...
}
}
In the example above, we're using the @ExceptionHandler annotation to handle binding errors.
Other types of errors can be handled using the @ExceptionHandler annotation. In the following example, we're using the @ExceptionHandler annotation to handle database errors:
@ControllerAdvice
public class DatabaseErrorHandler {
@ExceptionHandler(DataAccessException.class)
public ResponseEntity<?> handleDatabaseErrors(DataAccessException ex) {
// ...
}
}
In the example above, we're using the @ExceptionHandler annotation to handle database errors.
In this article, we've looked at how to handle errors in Spring Boot. We've started with a brief overview of the different types of errors that can occur, and then we've discussed how to handle them using the @ControllerAdvice annotation.