Global Exception Handling in Spring Boot

By Atul Rai | Last Updated: October 27, 2023 Previous       Next

Global Exception Handling in Spring Boot is a mechanism that allows you to centrally manage and handle exceptions that occur throughout your application. It helps you define a consistent approach to deal with exceptions, making your application more robust and providing a better experience for users. This approach typically involves creating a centralized component or class that intercepts and handles exceptions that may occur during the execution of your Spring Boot application.

Here’s how global exception handling works in Spring Boot, along with its benefits and an example:

1. Benefits of Global Exception Handling

1. Consistency: It ensures a consistent and uniform way to handle exceptions across your entire application, reducing code duplication and promoting a single point of control.
2. Separation of Concerns: It separates the error-handling logic from the business logic, which makes your code more maintainable and cleaner.
3. Improved User Experience: It allows you to provide meaningful error messages and responses to the user, making the application more user-friendly.
4. Logging and Reporting: Centralized exception handling can provide logging and reporting mechanisms for monitoring and debugging purposes.

Related Post: Spring @RestControllerAdvice Annotation Example

2. Global Exception Handling in Spring Boot

2.1. Create a Custom Exception Class: First, create a custom exception class to represent application-specific exceptions. For example, you can create a CustomException class that extends RuntimeException:

public class CustomException extends RuntimeException {
    public CustomException(String message) {
        super(message);
    }
}

2.2. Create a Global Exception Handler Class: Next, create a global exception handler class that will handle exceptions across your application. Annotate this class with @ControllerAdvice:

@ControllerAdvice
public class GlobalExceptionHandler {

    @ExceptionHandler(CustomException.class)
    public ResponseEntity<String> handleCustomException(CustomException ex) {
        return new ResponseEntity<>("Custom Exception: " + ex.getMessage(), HttpStatus.BAD_REQUEST);
    }

    @ExceptionHandler(Exception.class)
    public ResponseEntity<String> handleGenericException(Exception ex) {
        return new ResponseEntity<>("An error occurred: " + ex.getMessage(), HttpStatus.INTERNAL_SERVER_ERROR);
    }
}

In the code above, @ControllerAdvice indicates that this class provides exception handling across the entire application. It defines two exception handlers, one for CustomException and another for generic Exception.

2.3. Throwing Custom Exceptions: In your application’s code, when an error or exception occurs, you can throw the custom exception you created earlier. For example:

@RestController
public class MyController {
    @GetMapping("/someEndpoint")
    public ResponseEntity<String> someEndpoint() {
        if (someCondition) {
            throw new CustomException("This is a custom exception.");
        }
        return ResponseEntity.ok("Operation was successful.");
    }
}

In this example, when the /someEndpoint is accessed and someCondition is met, a CustomException is thrown. The global exception handler intercepts this exception and returns a customized response.

3. References

1. Annotation Interface ControllerAdvice – SpringDoc
2. Spring Boot RESTful CRUD Example with MySQL Database