SpringMVC 方法里返回json或跳到一个页面

习惯了用@ResponseBody来与移动端交互，忽然有个新的需求，如果移动端传递的参数是XX，则跳到一个页面。所以@ResponseBody不能用了，用回最原始的out.write();

@RequestMapping("/xxxxxx")public String getUrl(HttpServletRequest request, @RequestParam( "url") String url,                HttpServletResponse response, PrintWriter out) {    ResponseData responseData;    if(null != url) {        return "redirect:" + url;    }    response.setContentType("text/html;charset=utf-8");    response.setHeader("pragma", "no-cache");    response.setHeader("cache-control", "no-cache");    out.write("{\"xxx\":"\xxxx\"}");    return null;}