flex polygon 序列化为txt 文本

当我们要把一个地块导出为txt的时候，应该怎么写，这是比较有用的这样可以帮助我们存档之类的，这里是基于某个地方的独立坐标系，是基于自己发布地图，如果是用百度地图或者其他网上的地图可能不适用。

 package com.szpl.extension.util
 {
     import com.esri.ags.geometry.MapPoint;
     import com.esri.ags.geometry.Polygon;
     import com.esri.ags.layers.GraphicsLayer;
     import com.esri.ags.symbols.SimpleFillSymbol;
     import com.esri.ags.symbols.SimpleLineSymbol;
     import com.szpl.extension.util.shp.shp.ShpPolygon;

     import flash.geom.Point;

     public class PointPolygonExchange
     {
         public function PointPolygonExchange()
         {
         }

         private var _pointstr:String="";

         public function get pointstr():String
         {
             return _pointstr;
         }

         public function set pointstr(value:String):void
         {
             _pointstr = value;
         }

       //  "x,y x,y x,y*x,y x,y..."
       public function coordText_to_polygon(coordText:String):Polygon
       {
           var ringsText:Array = coordText.split("*");

           var polygon:Polygon = new Polygon();
           for each(var ringText:String in ringsText)
           {
               var ring:Array = coordText_to_Ring(ringText);
               if(ring==null)
                 continue;
               polygon.addRing(ring);
           }
           return polygon;
       }

       public var xyChange:String = "x";

       public function polygon_to_CoordText(polygon:*):String
       {
           var _polygon:Polygon = new Polygon();
           if (polygon is ShpPolygon)
           {
               _polygon = (polygon as ShpPolygon).toPolygon();
           }
           else
           {
               _polygon = polygon as Polygon
           }
           xyChange = "x";
           var polygonText:String="";
           for each(var ring:Array in _polygon.rings)
           {
               var ringText:String = ring_to_CoordText(ring);
               polygonText += ringText;
               polygonText += "*";
           }

           return polygonText.substr(0,polygonText.length -1);
       }

       public function polygon_to_CoordTextXY(polygon:*):String
       {
           xyChange = "y";
           var polygonText:String="";
           for each(var ring:Array in polygon.rings)
           {
               var ringText:String = ring_to_CoordText(ring);
               polygonText += ringText;
               polygonText += "*";
           }

           return polygonText.substr(0,polygonText.length -1);
       }

       private function ring_to_CoordText(points:Array):String
       {
           var ringText:String="";
           for each(var point:MapPoint in points)
           {
               var pointText:String = point_to_CoordText(point);
               ringText += pointText;
               ringText += " ";
           }
           return ringText.substr(0,ringText.length-1);
       }

       private function coordText_to_Ring(coordText:String):Array
       {
           if(coordText=="")
               return null;
           var pointsText:Array = coordText.split(" ");
           var ring:Array = new Array();
           for each(var pointText:String in pointsText)
           {
               if(pointText!="")
               {
                   var point:MapPoint = coordText_to_Point(pointText);
                   if (point != null)
                       ring.push(point);
               }

           }
           if (ring.length < 3)
               return null;
           ring.push(new MapPoint((ring[0] as MapPoint).x,(ring[0] as MapPoint).y));
           return ring;
       }

       private function point_to_CoordText(point:MapPoint):String
       {
          var x:String = point.x.toString();
          var y:String = point.y.toString();
          if(xyChange == "x")
              return x + "," + y;
          else
              return y + "," + x;
       }

       ///  "343.234,23423.534"
       private function coordText_to_Point(coordText:String):MapPoint{

           var coord:Array = coordText.split(",");
           if (coord.length != 2)
               return null;
           var x:Number = coord[1];
           var y:Number = coord[0];
           var point:MapPoint;
           if (x > y)
                point = new MapPoint(x, y, null);
           else
                point = new MapPoint(y, x, null);
           return point;
       }

       // "\r\n"  ====> " "
       public function txtFile_to_CoordText(txtFile:String):String
       {
           var regE:RegExp = new RegExp("\r\n", "g");
           var str:String = txtFile.replace(regE," ");
           return str;
       }

     }
 }