何时在 spring 中使用不同的请求方法

Question

I've been tasked with creating a simple REST API, where a single double is provided, and another one is derived from it according to some rules.

When creating a controller, I made the method for parsing said base double in two ways.

@GetMapping("calculate/{income:.+}")
public ResponseEntity<?> calculateEAT(@PathVariable double income){
  return ResponseEntity.ok(TaxDAO.addResult(income));
}

@PostMapping("calculate/{income:.+}")
public ResponseEntity<?> calculateEAT(@PathVariable double income){
  return ResponseEntity.ok(TaxDAO.addResult(income));
}

The only difference is the type of mapping used. The only difference I noticed was that I could type income in the browser address bar with GET mapping - and it worked. With post mapping, I could only get results using Postman.

I'm assuming it's possible to write an entire controller using GET mapping. I don't really feel like it's a good practice though. Are there any rules for using Request Methods in controllers?

Answer 1

GET and POST requests are different HTTP methods. The browser will do a GET request when you type something in the browser address bar, that is why you can only make it work in Postman (where you can select which HTTP method to use).

You should use GET when you want to retrieve something from the REST API. You should use POST when you want to submit something to the REST API, usually creating a resource or triggering some kind of process. You can read more about each HTTP method in the following online resources:

• https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods
• https://www.restapitutorial.com/lessons/httpmethods.html