cesium加载ArcGIS Server发布的地图服务（WMS)

 cesium加载代码如下：

var layer='0';
   for(i=1;i<2;i++)
   {
  layer+=','+i
   };
  // console.log(layer);

 var imageryProvider=new Cesium.WebMapServiceImageryProvider({
     url:'http://localhost:6080/arcgis/services/Example/yh/MapServer/WmsServer?',
      layers:layer,
      //crs:'EPSG:4326',
      parameters : {
     service : 'WMS',
      format: 'image/png',
     transparent:true
    },
  });
   viewer.imageryLayers.addImageryProvider(imageryProvider);