Скачать или смотреть Solving the Not Found Error for Spring Boot GET and POST Requests Using CrudRepository

Learn how to troubleshoot and fix the common `404 Not Found` errors in your Spring Boot REST API application, specifically when using `CrudRepository`.
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This video is based on the question https://stackoverflow.com/q/63822555/ asked by the user 'antonio0991' ( https://stackoverflow.com/u/9848960/ ) and on the answer https://stackoverflow.com/a/63824926/ provided by the user 'Surya Gaikwad' ( https://stackoverflow.com/u/6517224/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Troubleshooting 404 Not Found Errors in Spring Boot

Building a REST API can be tricky, especially when encountering errors that halt your progress. If you're getting a 404 Not Found error while trying to access your endpoint, you're not alone. Many developers run into this issue, particularly with Spring Boot applications that utilize CrudRepository.

In this guide, we'll troubleshoot a common symptom of improperly configured REST endpoints and offer you step-by-step guidance to resolve this issue.

The Problem

Imagine you're working on a REST API for a game store using Spring Boot. Everything seems to be set up as intended, yet upon accessing the URL localhost:8080/game, you are greeted with a perplexing 404 Not Found error. This error occurs without any apparent mistakes in your console logs, making it all the more frustrating.

Dissecting the Game Store Application

Let’s take a brief look at the primary components of the application, especially the controller where the REST endpoints are defined. Below are the relevant snippets of your code.

GameStoreApplication.java

[[See Video to Reveal this Text or Code Snippet]]

GameController.java

Here is where the main logic of the REST API lies:

[[See Video to Reveal this Text or Code Snippet]]

By reviewing this code, we can identify potential issues.

Understanding the Causes of the 404 Not Found

1. Endpoint Misconfiguration

One common reason for 404 Not Found errors in Spring Boot is endpoint misconfiguration, specifically the way you define your request mappings.

2. Missing GET and POST Annotations

Make sure that your @ GetMapping and @ PostMapping annotations do not have any extra parentheses. In the provided code, you had them specified incorrectly:

[[See Video to Reveal this Text or Code Snippet]]

They should be defined as:

[[See Video to Reveal this Text or Code Snippet]]

Proposed Solution

To fix the 404 Not Found error, ensure that your endpoint methods are correctly annotated without parentheses. Here's how they should look:

[[See Video to Reveal this Text or Code Snippet]]

Summary

The 404 Not Found error can be disruptive when building your game store API in Spring Boot. By ensuring your endpoint mappings are correctly set without extraneous parentheses, you can eliminate these frustrating errors and get your API running smoothly.

Key Takeaways:

Check for proper usage of @ GetMapping and @ PostMapping annotations.

Review your URL patterns and ensure they match your requests.

If issues persist, debug further to ensure your controller is registered correctly.

By following these guidelines, you should now be equipped to resolve the 404 Not Found issues in your REST API. Happy coding!