springmvc提供RestController方法接口返回json数据中文乱码

web应用使用@RestController @RequestMapping 注解提供http接口
项目中遇到被调用接口后返回的json数据中出现中文乱码的问题

@RequestMapping(method = RequestMethod.POST, value= "/sync")
    public String sync(@RequestBody JSonObject jsonObj) {
    	
    	String response = service.sync(jsonObj);
    	return response;
    }

调用方获取到返回response数据中中文乱码
"errorCode":"？？data"

@RequestMapping加上（produces = "application/json; charset=utf-8"）可以解决乱码问题

@RequestMapping(method = RequestMethod.POST, value= "/sync", produces = "application/json; charset=utf-8")
     public String sync(@RequestBody JSonObject jsonObj) {
    	
    	String response = service.sync(jsonObj);
    	return response;
    }

"errorCode":"设备data"