private DeferredResult<String> deferredResult = new DeferredResult<String>();
		
	@ResponseBody
    @GetMapping("/receive")
    public DeferredResult<String> receive() throws Exception {
        return deferredResult;
    }

    @ResponseBody
    @GetMapping("/send")
    public void send() throws Exception {
        deferredResult.setResult("Helloworld!!!");
    }
		
		

		
	private final List<DeferredResult<String>> deferredResultList = new ArrayList<DeferredResult<String>>();
	
    @ResponseBody
    @GetMapping("/receive")
    public DeferredResult<String> receive() throws Exception {
        DeferredResult<String> deferredResult = new DeferredResult<>();

        //先存起来，等待触发
        deferredResultList.add(deferredResult);
        return deferredResult;
    }

    @ResponseBody
    @GetMapping("/send")
    public void send() throws Exception {
        // 让所有hold住的请求给与响应
        deferredResultList.forEach(d -> d.setResult("say hello to all"));
    }		
		
		

DeferredResult 与 Callback 配合使用，用来获取 Callback 返回值

		
    @GetMapping("/tts")
    @Operation(summary = "音频合成")
    @ResponseBody
    public DeferredResult<ResponseJson> test(@RequestParam("text") String text, @RequestParam("filename") String filename) {
        DeferredResult<ResponseJson> deferredResult = new DeferredResult<ResponseJson>();
        speechSynthesizerService.tts(text, new XfyunCallback() {
            @Override
            public void onCallback(String sid, String text) {
                String audio = aliyunService.uploadMp3FromBase64(text, filename.concat(".mp3"));
                ResponseJson response = new ResponseJson(true, ResponseJson.Code.SUCCESS, "", audio);
                deferredResult.setResult(response);
            }
        });
        return deferredResult;
    }