cesium 加载geoserver wms服务

代码如下

//加载geoserverwms
    var wmslayer = new Cesium.WebMapServiceImageryProvider({
      url:"http://localhost:8880/geoserver/postgis/wms",
      layers:'postgis:ceshi0606',
      parameters: {
        transparent: true,
        format: "image/png",
        srs: "EPSG:4490",
        // 非必填
        styles: "",
      },
    });
    imageryLayers.addImageryProvider(wmslayer);