World Wind Java开发之十三——加载Geoserver发布的WMS服务（转）

这篇是转载的平常心博客，原地址见：http://www.v5cn.cn/?p=171

1、WMSTiledImageLayer类说明

一个WMSTiledImageLayer类对象只能对应一个WMS发布的服务图层，使用WMS服务时需要使用到WMS元数据描述类WMSCapabilities对象，我们使用WMSCapabilites类的静态方法retrieve来获得它的对象。WMSCapabilites对象可以包含WMS服务中所以的图层和图层样式，我们通过把需要显示的图层名称保存到AVList对象中，然后通过WMSCapabilites对象和AVList来创建WMSTiledImageLayer对象。我们可以通过一个请求地址来查看WMS服务所包含的元数据。例如：http://127.0.0.1:8080/geoserver/PostGIS/wms?request=GetGapabilities&Service=WMS 问号后面的地址是固定的，可以但看如下的XML:

<LayerqueryableLayerqueryable="1">
<Name>spearfish</Name>
<Title>spearfish</Title>
<Abstract>Layer-Group type layer: spearfish</Abstract>
<CRS>EPSG:26713</CRS>
<EX_GeographicBoundingBox>
<westBoundLongitude>-103.87791475407893</westBoundLongitude>
<eastBoundLongitude>-103.62278893469492</eastBoundLongitude>
<southBoundLatitude>44.37246687108142</southBoundLatitude>
<northBoundLatitude>44.50235105543566</northBoundLatitude>
</EX_GeographicBoundingBox>
<BoundingBoxCRSBoundingBoxCRS="EPSG:26713"minx="589425.9342365642"miny="4913959.224611808"maxx="609518.6719560538"maxy="4928082.949945881"/>
</Layer>
<LayerqueryableLayerqueryable="1">
<Name>tasmania</Name>
<Title>tasmania</Title>
<Abstract>Layer-Group type layer: tasmania</Abstract>
<CRS>EPSG:4326</CRS>
<EX_GeographicBoundingBox>
<westBoundLongitude>143.83482400000003</westBoundLongitude>
<eastBoundLongitude>148.47914100000003</eastBoundLongitude>
<southBoundLatitude>-43.648056</southBoundLatitude>
<northBoundLatitude>-39.573891</northBoundLatitude>
</EX_GeographicBoundingBox>
<BoundingBoxCRSBoundingBoxCRS="EPSG:4326"minx="-43.648056"miny="143.83482400000003"maxx="-39.573891"maxy="148.47914100000003"/>
</Layer>
<LayerqueryableLayerqueryable="1">
<Name>tiger-ny</Name>
<Title>tiger-ny</Title>
<Abstract>Layer-Group type layer: tiger-ny</Abstract>
<CRS>EPSG:4326</CRS>
<EX_GeographicBoundingBox>
<westBoundLongitude>-74.047185</westBoundLongitude>
<eastBoundLongitude>-73.907005</eastBoundLongitude>
<southBoundLatitude>40.679648</southBoundLatitude>
<northBoundLatitude>40.882078</northBoundLatitude>
</EX_GeographicBoundingBox>
<BoundingBoxCRSBoundingBoxCRS="EPSG:4326"minx="40.679648"miny="-74.047185"maxx="40.882078"maxy="-73.907005"/>
</Layer>
<LayerqueryableLayerqueryable="1">
<Name>省界_region</Name>
<Title>省界_region</Title>
<Abstract/>
<KeywordList>
<Keyword>features</Keyword>
<Keyword>省界_region</Keyword>
</KeywordList>
<CRS>EPSG:4326</CRS>
<CRS>CRS:84</CRS>
<EX_GeographicBoundingBox>
<westBoundLongitude>73.441277</westBoundLongitude>
<eastBoundLongitude>135.08693</eastBoundLongitude>
<southBoundLatitude>18.159829</southBoundLatitude>
<northBoundLatitude>53.561771</northBoundLatitude>
</EX_GeographicBoundingBox>
<BoundingBoxCRSBoundingBoxCRS="CRS:84"minx="73.441277"miny="18.159829"maxx="135.08693"maxy="53.561771"/>
<BoundingBoxCRSBoundingBoxCRS="EPSG:4326"minx="18.159829"miny="73.441277"maxx="53.561771"maxy="135.08693"/>
<Style>
<Name>polygon_x</Name>
<Title>Default Polygon</Title>
<Abstract>A sample style that draws a polygon</Abstract>
<LegendURLwidthLegendURLwidth="20"height="20">
<Format>image/png</Format>
<OnlineResourcexmlns:xlinkOnlineResourcexmlns:xlink="http://www.w3.org/1999/xlink"xlink:type="simple"xlink:href="http://localhost:8080/geoserver/cite/ows?service=WMS&request=GetLegendGraphic&format=image%2Fpng&width=20&height=20&layer=%3F%3F_region"/>
</LegendURL>
</Style>
</Layer>

里面的每一个Layer节点都是一个WMS图层。

2、例子

package gov.nasa.worldwindx.v5cn;

import gov.nasa.worldwind.avlist.AVKey;
import gov.nasa.worldwind.avlist.AVList;
import gov.nasa.worldwind.avlist.AVListImpl;
import gov.nasa.worldwind.ogc.wms.WMSCapabilities;
import gov.nasa.worldwind.wms.WMSTiledImageLayer;
import gov.nasa.worldwindx.examples.ApplicationTemplate;

import java.net.URI;
import java.net.URISyntaxException;

public class WMSLayerTest extends ApplicationTemplate {
    public static class AppFrame extends ApplicationTemplate.AppFrame{

        private static final long serialVersionUID = 1L;

        public AppFrame(){
            try {
                //请求地图的URL
                String uri = "http://127.0.0.1:8080/geoserver/PostGIS/wms";
                WMSCapabilities caps;
                URI serverURI = new URI(uri);

                //获得WMSCapabilities对象
                caps = WMSCapabilities.retrieve(serverURI);
                //解析WMSCapabilities数据
                caps.parse();

                AVList params = new AVListImpl();

                //图层的名称
                params.setValue(AVKey.LAYER_NAMES, "planet_osm_line");
                //地图服务的协议，这里是OGC:WMS
                params.setValue(AVKey.SERVICE_NAME, "OGC:WMS");
                //获得地图的uri，也就是上面定义的uri
                params.setValue(AVKey.GET_MAP_URL, uri);
                //在本地缓存文件的名称
                params.setValue(AVKey.DATA_CACHE_NAME, "planet_osm_line");
                params.setValue(AVKey.TILE_URL_BUILDER, new WMSTiledImageLayer.URLBuilder(params));

                WMSTiledImageLayer imageLayer = new WMSTiledImageLayer(caps,params);
                //图层名称
                imageLayer.setName("planet_osm_line");
                imageLayer.setEnabled(true);
                //图层的透明度
                imageLayer.setOpacity(1);
                //图层的最大显示高度
                imageLayer.setMaxActiveAltitude(33500000);
                getWwd().getModel().getLayers().add(imageLayer);
                getLayerPanel().update(getWwd());

            } catch (URISyntaxException e) {
                e.printStackTrace();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }

    }
public static void main(String[] args) {
        ApplicationTemplate.start("WMS图层", WMSLayerTest.AppFrame.class);
    }
}

请求的URL就是GeoServer中点击【OpenLayers】中的路径：

图层名称就是定义发布服务是的名称，可以在GeoServer中找到。