为什么我无法发送正确的服务器状态作为响应，而是在我点击端点时得到“无响应”？

Question

I was testing an endpoint that is supposed to return a JSON.

Works great. But when there is an exception (like a forbidden) it should return a proper error code and message.

Right now im doing it like this:

@ResponseBody
@GetMapping(produces = APPLICATION_JSON_UTF8_VALUE)
public ResponseEntity getInfo() {
    try{
        //..do something
    }catch(Exception e){

        return new ResponseEntity<>("Error calculating the required information", null, HttpStatus.INTERNAL_SERVER_ERROR);
    }
}

Instead when I curl the url or with swagger I get this:

Request URL
http://localhost:8081/info
Request Headers
{
  "Accept": "application/json;charset=UTF-8"
}
Response Body
no content
Response Code
0
Response Headers
{
  "error": "no response from server"
}

And yes, I am hitting the endpoint (I debugged it).

Any idea why this response is returning? Thanks.

Answer 1

You need change method sign

public ResponseEntity<Void> getInfo() {

and also change return type with

return new ResponseEntity<Void>(HttpStatus.INTERNAL_SERVER_ERROR);

If you want return a specific message you need to create custom exception class.

You can find an example the following project link on github : https://github.com/in28minutes/spring-microservices/tree/master/02.restful-web-services/src/main/java/com/in28minutes/rest/webservices/restfulwebservices

Answer 2

You can change your code like this

@ResponseBody
@GetMapping(produces = APPLICATION_JSON_UTF8_VALUE)
public ResponseEntity<String> getInfo() {
    try {
        //..do something
    } catch(Exception e) {

        return new ResponseEntity<>("Error calculating the required information", null, HttpStatus.INTERNAL_SERVER_ERROR);
    }
}

Definition of ResponseEntity code is like this.

public ResponseEntity(T body, MultiValueMap<String, String> headers, HttpStatus status) 

You have to match generic type.

One thing interesting is I made same code you attached, and it worked well. (returned 500 error with response body)