習慣了用@ResponseBody來與移動端互動，忽然有個新的需求，如果移動端傳遞的引數是XX，則跳到一個頁面。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;
}