web-controller中返回体设置header中content-type

package com.example.demo.controller;

import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.bind.annotation.GetMapping;


import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;

@RestController
public class Test1Controller {
    @GetMapping("/test1")
    public ResponseEntity<String> get() {
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON); // 设置 Content-Type
        return ResponseEntity.ok()
            .headers(headers)
            .body("{"message": "Hello World"}");
    }
}