Exception Handling in Spring Boot

Introduction

In this article, I will try to explain exception handling in the spring boot framework in easy-to-understand words so that beginners can easily understand the concept and start implementing it.

When you're developing an application with Spring Boot, it's important to handle errors that might occur. These errors can be divided into- runtime errors that happen when your code is running and checked errors caught by the compiler before your code is executed. Sometimes, you may also want to create custom errors for specific situations in your application.

To handle these errors, Spring Boot provides a way to catch and handle them. You can use the @ExceptionHandler annotation to write code that handles specific errors. This code can be written in a centralized location and executed whenever the specified error occurs.

For example, if you want to handle an error that occurs when a user enters an invalid input, you can create a method that handles this error like so,

@ExceptionHandler(InvalidInputException.class)
public ResponseEntity<String> handleInvalidInputException(InvalidInputException ex) {
    return ResponseEntity.badRequest().body("Invalid input: " + ex.getMessage());
}

In this example, the @ExceptionHandler annotation specifies that this method should be executed when an InvalidInputException is thrown. The method takes an InvalidInputException as a parameter and returns a ResponseEntity with a bad request status code and a message that includes the error message.

You can customize the response that is sent back to the user when an error occurs by using the ResponseEntity class. This allows you to provide the user with more detailed information about the error.

For example, you can create a method that handles all exceptions and returns a custom error response like so,

@ControllerAdvice
public class GlobalExceptionHandler {

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

In this example, the @ControllerAdvice annotation specifies that this class should handle all exceptions in the application. The handleException method takes an Exception as a parameter and returns a ResponseEntity with an internal server error status code and a message that includes the error message.

Summary

Handling exceptions in a Spring Boot application is important to ensure that your application runs smoothly and provides a good user experience. Using the features provided by Spring Boot, you can write reliable and easy to maintain code.

I hope I was able to keep the concept very simple. Once you understand the basics, you can always deep dive into the framework's documentation to learn more.