贴一个自己写的json转xml 的HTTPServiceUtils对象

if (!this.HTTPServiceUtils) {
    HTTPServiceUtils = {    
    };
}
(function () {    
        var XMLHttpReq ={
        _objPool: [],//xmlhttp建立连接池      
        _getInstance:function (){
            for (var i = 0; i < this._objPool.length; i ++){
                if (this._objPool[i].readyState == 0 || this._objPool[i].readyState == 4){
                    return this._objPool[i];
                }
            }
            // IE5中不支持push方法
            this._objPool[this._objPool.length] = this._createObj();
            return this._objPool[this._objPool.length - 1];
        },
        _createObj: function (){
            if (window.XMLHttpRequest){
                var objXMLHttp = new XMLHttpRequest();
            }else{
                var MSXML = ['MSXML2.XMLHTTP.5.0', 'MSXML2.XMLHTTP.4.0', 'MSXML2.XMLHTTP.3.0', 'MSXML2.XMLHTTP', 'Microsoft.XMLHTTP'];
                for(var n=0; n<MSXML.length; n++){
                    try{
                        var objXMLHttp = new ActiveXObject(MSXML[n]);
                        break;
                    }catch(e){}
                }
            }          
            // mozilla某些版本没有readyState属性
            if (objXMLHttp.readyState == null){
                objXMLHttp.readyState = 0;
                objXMLHttp.addEventListener("load", function (){
                    objXMLHttp.readyState = 4;
                    if(typeof objXMLHttp.onreadystatechange == "function"){objXMLHttp.onreadystatechange();}
                },  false);
            }
            return objXMLHttp;
        },
        // 发送请求(方法[post,get], 地址, 数据, 回调函数,数据模板)
        sendReq: function (method, url, data, callback,dataset){
            var objXMLHttp = this._getInstance();
            with(objXMLHttp){
                try{
                    open(method, url, true);
                    // 设定请求编码方式
                    setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
                    send(data);
                    onreadystatechange = function (){
                        if (objXMLHttp.readyState == 4 && (objXMLHttp.status == 200 || objXMLHttp.status == 304)){
                            callback(objXMLHttp,dataset);
                        }
                    }
                }catch(e){alert(e);}
            }
        }
      };  
      var DynamicFields;//MAP格式 DynamicFields.keys()所有的键 DynamicFields.values()所有的值
      var Datasetname;
      var Dataset;
      var _xml;
    //设置map字段
    function setMap(_dynamicfields){
            var map = new Map();//创建map对象
            var fields  = new Array();                   
            fields = fields.str2arr(_dynamicfields);
            for(var i in fields) {
                if(!isNaN(i)){
                    var xx = new  Array();
                    xx = fields[i].split(":");
                    map.put(xx[0],xx[1]);
                 }
             } 
            DynamicFields = map;
    }
    //数组对象的扩展增加一个字串转数组的方法
    Array.prototype.str2arr=function(string){
    var s;
    if(string.indexOf(";")!=-1) s=string.split(";");
    if(string.indexOf("^")!=-1) s=string.split("^");
    arr=this;
    for(i=0;i<s.length;i++){
        arr = arr.concat(s[i]);
      }
       return arr;
    }
    //清除数组内容
    Array.prototype.clear=function(){
    this.splice(0,this.length);
    }   
    // 回调函数jsonResponse
       function jsonResponse(originalRequest,_dataset) {
         var fields  = new Array();  
         fields = _dataset._fields.keys(); 
         var name = _dataset._name;
            var myobj = eval("(" + originalRequest.responseText + ")");
            _xml = JsonToXml(myobj,name,fields)    
            InitialDataset(_xml,_dataset);
        } 
      //json 到 xml 的转换  
        function JsonToXml(_jsonobj,_datasetname,_fields){
          var xml = "<xml id=\"__"+_datasetname+"\" style=\"display: none\">";  
              xml = xml +"<records  possibleCount=\"1\" pageCount=\"1\" loadedPages=\"1\">";
          var recNum=0;
          var itemCount = _jsonobj.itemCount;
          var fieldsCount = _fields.length;
          while(itemCount>0)
          {
              xml=xml+"<record id=\""+(recNum+1)+"\" pageIndex=\"1\" state=\"none\"><new>";
              xml=xml+"s";//选择框占位符 true 表示勾选框勾住
              for(var i=0;i<fieldsCount;i++){
                xml=xml+"^"+_jsonobj.list[recNum][_fields[i]];
              }
           xml= xml+"</new></record>";
           recNum++;
           itemCount--;
          }  
         xml = xml +"</records>";
         xml = xml +"</xml>";
         return xml;
    }  
    //初始化数据集
        function InitialDataset(_xml,_dataset)
        {
              var XMLDoc; 
              _dataset.clearData();  
           XMLDoc = new ActiveXObject("Msxml2.DOMDocument");
           XMLDoc.async = false;
           if (XMLDoc.loadXML(_xml))
           {
            $cq=XMLDoc.getElementsByTagName("xml/records")[0];
            _dataset.$8p($cq,true,null,null);
            return _dataset;
              }
           else
           {
            alert("初始化数据集错误！");
           }
        }                                  
    if(typeof HTTPServiceUtils.httpGet !== 'function'){
              HTTPServiceUtils.httpGet = function(url,dataset){
                     XMLHttpReq.sendReq("get",url,null,jsonResponse,dataset);      
              }
    }  
    if(typeof HTTPServiceUtils.httpPost !== 'function'){
              HTTPServiceUtils.httpPost = function(url,parameters,dataset){
                     XMLHttpReq.sendReq("post",url,parameters,jsonResponse,dataset);         
              }
    }
    //初始化表格
    if(typeof HTTPServiceUtils.initDataTable !== 'function'){
              HTTPServiceUtils.initDataTable = function(_datatable,_dataset){
                 _datatable.addColumn("select");
                 for(var i=0;i<_dataset._fields.size();i++){
                    var _f  = _datatable.addColumn(_dataset._fields.element(i).key);
                        _f.setField(_dataset._fields.element(i).key)
                        _f.setLabel(_dataset._fields.element(i).value)                
                 }// DynamicFields.keys()所有的键 DynamicFields.values()所有的值
              }
    }
    //通过模板取得一个数据集实例
    if(typeof HTTPServiceUtils.initDataset !== 'function'){
              HTTPServiceUtils.initDataset = function(_dynamicfields,_datasetname,_keyname){
                    Datasetname = _datasetname;
                    Dataset = BX.create("Dataset",null,_datasetname,"");                 
                    setMap(_dynamicfields);
                    Dataset._name = Datasetname;
                    Dataset._fields = DynamicFields;
                    Dataset._keyname = _keyname;
                    Dataset.addField("select","string");
                    for(var i=0;i<DynamicFields.size();i++){
                       var _f = Dataset.addField(DynamicFields.element(i).key,"string");
                       _f.setLabel(DynamicFields.element(i).value);
                       if(DynamicFields.elements[i].key == "key")
                       _f.setToolTip(DynamicFields.element(i).value);
                    }
                    return Dataset;                          
          }
    }       
})();