Spring Boot REST API: Handling multiple request headers for different versions of endpoints
I'm performance testing and I'm currently developing a Spring Boot REST API where I need to support multiple versions of the same endpoint. Specifically, I have an endpoint that returns user data. I want to be able to handle different versions based on a custom request header, say `X-API-Version`. However, I am working with issues where the controller sometimes defaults to the latest version, even when an older version is specified. Here's a snippet of what I've tried: ```java @RestController @RequestMapping("/api/users") public class UserController { @GetMapping public ResponseEntity<User> getUser(@RequestHeader(value = "X-API-Version", defaultValue = "1.0") String apiVersion) { if (apiVersion.equals("1.0")) { return ResponseEntity.ok(getUserV1()); } else if (apiVersion.equals("2.0")) { return ResponseEntity.ok(getUserV2()); } else { return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(null); } } private User getUserV1() { return new User("John", "Doe"); // Simplified response for version 1 } private User getUserV2() { return new User("John", "Doe", "john.doe@example.com"); // Enhanced response for version 2 } } ``` I've tested it using Postman, sending requests with different `X-API-Version` headers, but I keep getting the version 2 response, even when I specify version 1. The logs show that the header is being read correctly, but the method isn't branching as expected. I'm using Spring Boot 2.6.4 and Jackson 2.13.1. I've also tried putting a breakpoint in the controller to debug the flow, and it seems the `apiVersion` is being received correctly, yet it falls through to the version 2 logic. I've cleared my Postman cache and even tested it in incognito mode to rule out any caching issues. How can I ensure that the different API versions are properly handled based on the request header? Any insights or solutions would be greatly appreciated! The project is a desktop app built with Java.