Exception Handling in Spring Boot - How to do it right?

Ah, the realm of Exception Handling in Spring Boot! Prepare yourself for an enchanting journey filled with whimsical code and a touch of humor. As your jolly Java expert, I shall guide you through the magical land of proper Exception Handling in Spring Boot. So, let's embark on this delightful quest!

1. The Power of @ControllerAdvice: Imagine a magical spell that can handle exceptions across your entire Spring Boot application. With the help of @ControllerAdvice, you can create a global exception handler that gracefully deals with exceptions.

   import org.springframework.http.ResponseEntity;
   import org.springframework.web.bind.annotation.ControllerAdvice;
   import org.springframework.web.bind.annotation.ExceptionHandler;
   
   @ControllerAdvice
   public class GlobalExceptionHandler {
   
       @ExceptionHandler(Exception.class)
       public ResponseEntity<String> handleException(Exception ex) {
           // Handle the exception and provide an appropriate response
           return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR)
                   .body("Oops! Something went wrong. Please try again later.");
       }
   }
   

   In this whimsical example, we create a GlobalExceptionHandler using the @ControllerAdvice annotation. The @ExceptionHandler method handles any Exception thrown within the application. You can customize the logic inside the method to handle specific exceptions and provide meaningful responses to your users.

2. Custom Exception Classes: Imagine crafting your own magical exception spells, tailored to specific situations. By creating custom exception classes, you can encapsulate the specific details of each exception and handle them separately.

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

   In this whimsical example, we create a CustomException class that extends RuntimeException. You can add additional fields, methods, or constructors as needed to convey specific information about the exception.

3. Handling Custom Exceptions: Picture yourself casting spells to handle your custom exceptions. By annotating your exception classes with @ResponseStatus and defining corresponding exception handlers, you can gracefully handle these custom exceptions.

   import org.springframework.http.HttpStatus;
   import org.springframework.web.bind.annotation.ExceptionHandler;
   import org.springframework.web.bind.annotation.ResponseStatus;
   
   @ControllerAdvice
   public class CustomExceptionHandler {
   
       @ExceptionHandler(CustomException.class)
       @ResponseStatus(HttpStatus.BAD_REQUEST)
       public ResponseEntity<String> handleCustomException(CustomException ex) {
           // Handle the custom exception and provide an appropriate response
           return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(ex.getMessage());
       }
   }
   

   In this whimsical example, the CustomExceptionHandler class handles the CustomException specifically. The @ExceptionHandler annotation identifies the exception to handle, and the method provides the logic to handle the exception and generate an appropriate response.

4. Logging the Magic: Imagine keeping a magical journal of your exception encounters. By incorporating logging, you can capture valuable information about exceptions, aiding in troubleshooting and debugging.

   import org.slf4j.Logger;
   import org.slf4j.LoggerFactory;
   
   @ControllerAdvice
   public class GlobalExceptionHandler {
   
       private static final Logger LOGGER = LoggerFactory.getLogger(GlobalExceptionHandler.class);
   
       @ExceptionHandler(Exception.class)
       public ResponseEntity<String> handleException(Exception ex) {
           // Log the exception for future reference
           LOGGER.error("Exception occurred:", ex);
   
           // Handle the exception and provide an appropriate response
           return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR)
                   .body("Oops! Something went wrong. Please try again later.");
       }
   }
   

   In this whimsical example, we add logging using the SLF4J logging framework. By logging the exception, you create a breadcrumb trail of magical mishaps that can aid in diagnosing issues.

Now, my fellow wizards of Spring Boot, go forth and handle exceptions with grace and humor! May your spells of Exception Handling enchant your users and make debugging a joyous adventure!