ArcGIS Server测距

public void measureDistance(MapEvent event){
    WebMap webMap = webContext.getWebMap();
    WebGeometry webGeometry=event.getWebGeometry().toMapGeometry(webMap);
    WebPolyline webPolyline = (WebPolyline)webGeometry;
    WebSpatialReference webSpatialReference=webGeometry.getSpatialReference();
   
    lenth=MeasureUtil.getDistance(webPolyline,webSpatialReference);
    System.out.println("lenth:"+lenth);
//    webContext.refresh();
}