form表单数据封装成json格式并提交给服务器的实现方法

<form action="#" id="costform">
<input type="hidden" id="userid" name="userid"/>
<div id="cost">
 <img src='<%=path %>/cvc/center/images/close.png' class="close" style="width:34px;position:absolute;right:0px;top:0px;"></img>
 <h2 style="font-weight: bolder;font-size: 14px;">更改该注册订单的收费状态</h2>
 <ul>
 <li>
  <label for="report">
   　是否已报到：
  </label>
  <input type="radio" id="baodao1" name="baodao" value="1"/>是
  <input type="radio" id="baodao0" name="baodao" value="0"/>否
 </li>
 <li>
  <label for="name">
   　　姓　　名：
  </label>
  <span id="costname"></span>
 </li>
 <li>
  <label for="type">
   　　注册类型：
  </label>
  <span id="costtype"></span>
 </li>
 <li>
  <label for="sure_fee">
   　在线支付手续费：
  </label>
  <span id="costtype">0</span>
 </li>
 <li>
  <label for="sure_fee">
   　 应收费金额：
  </label>
  <span id="price"></span>
 </li>
 <li>
  <label for="already_fee">
   　 已收费金额：
  </label>
  <input type="text" id="pay_" name="pay"/>
 </li>
 <li>
  <label for="owe">
   　　欠　　款：
  </label>
  <span id="qianpay"></span>
 </li>
 <li>
  <label for="fee_type">
   　　付款方式：
  </label>
  <input type="radio" id="paytype1" name="paytype" value="3"/>银行
  <input type="radio" id="paytype2" name="paytype" value="4"/>邮局
  <input type="radio" id="paytype3" name="paytype" value="5"/>现金
  <input type="radio" id="paytype4" name="paytype" value="2"/>在线支付
 </li>
 <li>
  <label for="fee_evidence">
     是否收到汇款凭证：
  </label>
  <input type="radio" id="isreceiveproof1" name="isreceiveproof" value="1"/>是
  <input type="radio" id="isreceiveproof0" name="isreceiveproof" value="0"/>否
 </li>
 <li>
  <label for="fa_piao">
   　　发票抬头：
  </label>
  <span id="billtitle"></span>
 </li>
 
  <li>
  <label for="fa_piao">
   　　发票编号：
  </label>
   <input type="text" id="billcode" name="billcode"/>
 </li>
 <li>
  <label for="check_evidence">
   是否已开发票：
  </label>
  <input type="radio" id="isbill1" name="isbill" value="1"/>是
  <input type="radio" id="isbill0" name="isbill" value="0"/>否
 </li>
 <li>
  <label for="get_evidence">
   是否已领发票：
  </label>
  <input type="radio" id="isdrawbill1" name="isdrawbill" value="1"/>是
  <input type="radio" id="isdrawbill0" name="isdrawbill" value="0"/>否
 </li>
 <li>
 
  <label for="date">
   已发确认日期：
  </label>
  <span id="confirmdate"></span>
  <!-- <input type="text" id="confirmdate" name="confirmdate"/> --> 
  <!-- <input id="confirmdate" name="confirmdate" class="text" type="text" onclick="wdatepicker()"/> -->
 </li>
 <li>
  <label for="check_letter">是否已发确认函：</label>
  <span id="isconfirminvitation"></span>
 </li>
  <li>
  <label for="fa_piao">在线支付状态：</label>
  <span id="paystring"></span>
 </li>
 </ul>
 <div class="fee_opr">
  <button type="button" class="fee_sure" style="border: none;background: #003260;color: #ffffff;padding: 3px 30px;margin-left: 10px;border-radius: 0px;">确定</button>
  <button type="button" class="fee_cancel" style="border: none;background: #003260;color: #ffffff;padding: 3px 30px;margin-left: 10px;border-radius: 0px;">关闭</button>
 </div>
</div>
</form>

$(".fee_sure").click(function () {
  var dataobj = $("#costform").serialize();
  var paytype = $('input[name="paytype"]:checked').val();
  if(paytype == undefined){
   alert("请选择付款类型");
   return ;
  }else{
   $.ajax({
    url:"/webcenter.do?method=saveusermessage",
    type: "post", 
    datatype:"json",
    data:dataobj,
    cache:false,
    ifmodified:true,
    success:function(json){
      if(json.flag == 1){
       alert("1234");
      }
    }
   })
  }
 })

@requestmapping(params ="method=saveusermessage",method=requestmethod.post)  //导入发言
     public void saveusermessage(int userid,httpservletrequest request,httpservletresponse response){
      try {
       httpsession session = this.getsession(request);
       adminuser adminuser = session.getattribute("centeradminuser") == null?null:(adminuser) session.getattribute("centeradminuser");
       if(adminuser == null){
        try {
         response.sendredirect(request.getcontextpath()+"/center/index.jsp");
        } catch (exception e) {
         e.printstacktrace();
        }
       }else{
        string billnumber = request.getparameter("billcode")==null?"":request.getparameter("billcode");
        string isbaodao = request.getparameter("baodao")==null?"0":request.getparameter("baodao");
        string haspay = request.getparameter("pay")==null?"0":request.getparameter("pay");
        string paytype = request.getparameter("paytype")==null?"0":request.getparameter("paytype");
        string isfkpz = request.getparameter("isreceiveproof")==null?"0":request.getparameter("isreceiveproof");
        string isykfp = request.getparameter("isbill")==null?"0":request.getparameter("isbill");
        string isylfp = request.getparameter("isdrawbill")==null?"0":request.getparameter("isdrawbill");
        jsonobject jsonobject = new jsonobject();
        //adminuserconferences adminuserconferences = webservice.getadminuserconferences(adminuser.getadminuserid());
        userinfo userinfo = webservice.getuserinfobyid(userid);
        if(userinfo!=null)
        {
         jsonobject.accumulate("flag",1);
         chcreguser chcreguser = webservice.getchcreguser(userid);
         if(chcreguser!=null)
         {
          chcreguser.sethaspay(integer.parseint(haspay));
          chcreguser.setpaytype(integer.parseint(paytype));
          if(chcreguser.gethaspay()-chcreguser.getpay()==0)
          {
           chcreguser.setstatetype(1);
          }
          webservice.saveobject(chcreguser);
          userinfo.setisbaodao(integer.parseint(isbaodao));
          userinfo.setisfkpz(integer.parseint(isfkpz));
          userinfo.setbillnumber(billnumber);
          userinfo.setisylfp(integer.parseint(isylfp));
          userinfo.setisykfp(integer.parseint(isykfp));
          webservice.saveobject(userinfo);
          jsonobject.accumulate("pay", chcreguser.getpay());
          jsonobject.accumulate("haspay", chcreguser.gethaspay());
         }
        }else {
         jsonobject.accumulate("flag",0);
        }
        writejson(response, jsonobject.tostring());
       }
      } catch (exception e) {
       e.printstacktrace();
      }
     }