JQuery异步获取返回值中文乱码的解决方法

用jqgrid异步获取列表值，遇到个问题，服务器端从数据库取到的数据没有出现中文乱码问题（日志打出来是没有乱码的），但是异步传到客户的时候却出现了乱码。 服务器端已经编码过了（UTF-8编码）。开始一直怀疑是客户端的问题，比如客户端和服务器端编码不一致啊，也怀疑是不是jqGrid工具函数中少配了 contentType: "application/x-www-form-urlencoded; charset=utf-8",   等等问题。

结果都不是，纠结了几个小时，后来经过大牛的提醒发现，原来代码还是出在服务器端，疏忽了。

@RequestMapping(value = "/searchUserList.form")
  @ResponseBody
  public void searchUserList(int page, int rows, HttpServletRequest request, HttpServletResponse response) throws IOException{
    System.out.println("idcard="+idCard+"\n page="+page+"\n rows="+rows);
 
    List<User> list = userService.findByIDCard(idCard);
     
    int totalRecord = list.size();
    int totalPage = totalRecord%rows == 0 ? totalRecord/rows : (totalRecord/rows+1);
     
    int index = (page-1)*rows;
    int pageSize = rows;
     
    String json = "{\"total\": \""+totalPage+"\", \"page\": \""+page+"\", \"records\": \""+totalRecord+"\", \"rows\": ["; 
    for (int i = index; i < pageSize + index && i<totalRecord; i++) { 
      User u = list.get(i);
      json += "{\"id\":\"" + u.getUserId() + "\",\"userName\":\""+u.getUserName()+"\",\"idCard\":\""+
      u.getIdCard() +"\",\"userTel\":\""+u.getUserTel()+"\",\"userSex\":\""+u.getUserSex()+
      "\",\"bankCard\":\""+u.getBankCard()+"\",\"cardStatus\":\""+u.getCardSatus()+"\",\"createTime\":\""+
      u.getCreateTime()+"\"}";
      if (i != pageSize + index - 1 && i != totalRecord - 1) { 
        json += ","; 
      } 
    } 
    json += "]}";
    request.setCharacterEncoding("utf-8"); //这里不设置编码会有乱码
    response.setContentType("text/html;charset=utf-8");
    response.setHeader("Cache-Control", "no-cache"); 
    PrintWriter out = response.getWriter(); //输出中文，这一句一定要放到response.setContentType("text/html;charset=utf-8"), response.setHeader("Cache-Control", "no-cache")后面，否则中文返回到页面是乱码 
    out.print(json.toString());
    out.flush();
    out.close();
  }