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

        

        
        
    }
}