Spring MVC: How to Manage Multiple Content Negotiation Strategies for Different Endpoints?
I'm trying to figure out I'm building a feature where I'm maintaining legacy code that I've been banging my head against this for hours... I'm relatively new to this, so bear with me. I'm working on a personal project and I'm currently working on a Spring MVC application (version 5.3.12) where I need to handle different content negotiation strategies for various endpoints. Specifically, I want to serve JSON responses for a REST API and HTML responses for a web interface. However, I'm running into an issue where the content negotiation seems to be conflicting, leading to unexpected responses. For instance, when I access the `/api/data` endpoint (which should return JSON), I sometimes get HTML instead, especially when I include the `Accept: text/html` header in my request. Here’s a snippet of my configuration: ```java @Configuration @EnableWebMvc public class WebConfig implements WebMvcConfigurer { @Override public void configureContentNegotiation(ContentNegotiationConfigurer configurer) { configurer.favorPathExtension(false) .ignoreAcceptHeader(false) .defaultContentType(MediaType.APPLICATION_JSON) .mediaType("json", MediaType.APPLICATION_JSON) .mediaType("html", MediaType.TEXT_HTML); } } ``` In my controller, I have: ```java @Controller public class DataController { @GetMapping(value = "/api/data", produces = MediaType.APPLICATION_JSON_VALUE) @ResponseBody public ResponseEntity<Data> getData() { return ResponseEntity.ok(new Data("some data")); } @GetMapping(value = "/web/data", produces = MediaType.TEXT_HTML_VALUE) public String getWebData(Model model) { model.addAttribute("data", "some data"); return "dataView"; // refers to a Thymeleaf template } } ``` I have tried adjusting the `ContentNegotiationConfigurer` settings by adding `.defaultContentType(MediaType.APPLICATION_JSON)` to ensure the API always defaults to JSON. However, it hasn't resolved the issue. Additionally, I've confirmed that the correct endpoint is being hit based on the URL, but the response type still varies unexpectedly. Has anyone faced a similar issue or can offer insights into how to properly configure Spring MVC to handle multiple content negotiation strategies for different endpoints without conflicts? Any advice on best practices or configurations would be greatly appreciated. My development environment is macOS. Any help would be greatly appreciated! How would you solve this? This is for a REST API running on CentOS. I'd love to hear your thoughts on this. I've been using Java for about a year now. Has anyone else encountered this? My development environment is Windows 10. Is there a better approach?