同一RestEndpoint映射两个不同方法：如何根据produces匹配调用？

Absolutely! This is exactly what the produces attribute is designed to handle in Spring MVC (which your code is using). Let me break down how this works clearly:

Core Idea #

Spring MVC uses the Accept HTTP request header sent by the client to match against the produces value of your controller methods. That's the key mechanism here.

Using your example:

• The getUser() method is set to produce application/json (via MediaType.APPLICATION_JSON_VALUE)
• The getBinUser() method produces application/octet-stream (via MediaType.APPLICATION_OCTET_STREAM_VALUE)

How Clients Trigger Each Method #

Here's how different client requests will route to the right method:

• When the client sends Accept: application/json: Spring will call getUser(), since its produces value matches the requested media type.
• When the client sends Accept: application/octet-stream: The request will go to getBinUser() instead.
• If no Accept header is sent: Spring usually defaults to the first matching method it finds (but it's better to always specify the Accept header to avoid ambiguity).

Test with curl #

You can easily test this with curl commands:

• Call getUser():

  curl -H "Accept: application/json" http://your-server-address/v1/v2/123
  

• Call getBinUser():

  curl -H "Accept: application/octet-stream" http://your-server-address/v1/v2/123
  

Edge Cases to Keep in Mind #

• Multiple Accept values: If the client sends something like Accept: application/json, application/octet-stream;q=0.8, Spring uses content negotiation rules to pick the highest-priority match (the q value is the quality factor, higher means more preferred).
• No matching media type: If the client requests a type neither method supports (like text/plain), Spring will return a 406 Not Acceptable error.

Quick Summary #

Yes, the produces attribute directly determines which method is called, and the client needs to send the corresponding Accept header to target the right one. This is a standard REST pattern for serving different representations of the same resource.

内容的提问来源于stack exchange，提问作者CuriousMind