geoserver+openlayers实例
geowebcache为开源地图Title发布，在线服务．geowebcache会根据你的配置信息，把相应的地图图层切好图，存放在磁盘中，然后在使用openlayer加载地图服务的时候，把地图服务的地址指向geowebcache，geowebcache接收到这些请求后，会根据请求的位置和比例尺在切片目录中找到对应的瓦片，然后返回给你，省去了动态生成地图的过程，速度大幅度提高，而且由于请求的图片资源是事先生成好的，浏览器加载这些图片之后，下一次再去请求同样的图片，就会从浏览器的缓存中拉去，速度进一步提高！
下面说一下geowebcache的配置使用。首先下载war包，在tomcat中解压后，会在WEB-INF目录下找到一系列配置文件，先找到web.xml，然后在web-app根元素下添加：
<context-param> <param-name>GEOWEBCACHE_CACHE_DIR</param-name> <param-value>D:/data/cache</param-value> </context-param>
param-value的值就是你要存放geowebcache瓦片的位置，配置好这里，重启tomcat，你会发现在你的瓦片目录下生成了一些文件，其中就有geowebcache.xml，这个文件是geowebcache配置的关键所在，以下是这个文件的配置信息：
<?xml version="1.0" encoding="utf-8"?> <gwcConfiguration xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://geowebcache.org/schema/1.5.3" xsi:schemaLocation="http://geowebcache.org/schema/1.5.3 http://geowebcache.org/schema/1.5.3/geowebcache.xsd"> <version>1.5.3</version> <backendTimeout>120</backendTimeout> <serviceInformation> <title>GeoWebCache</title> <description>GeoWebCache is an advanced tile cache for WMS servers.It supports a large variety of protocols and formats, including WMS-C, WMTS, KML, Google Maps and Virtual Earth.</description> <keywords> <string>WFS</string> <string>WMS</string> <string>WMTS</string> <string>GEOWEBCACHE</string> </keywords> <serviceProvider> <providerName>xx</providerName> <providerSite>http://blog.csdn.net/xx</providerSite> <serviceContact> <individualName>xx</individualName> <positionName></positionName> <addressType></addressType> <addressStreet>xx</addressStreet> <addressCity>xx</addressCity> <addressAdministrativeArea>xx</addressAdministrativeArea> <addressPostalCode>010010</addressPostalCode> <addressCountry>中国,China</addressCountry> <phoneNumber></phoneNumber> <faxNumber></faxNumber> <addressEmail></addressEmail> </serviceContact> </serviceProvider> <fees>NONE</fees> <accessConstraints>NONE</accessConstraints> </serviceInformation> <gridSets> <!-- Grid Set Example, by default EPSG:900913 and EPSG:4326 are defined --> <gridSet> <!-- This does not have to be an EPSG code, you can also have multiple gridSet elements per SRS --> <name>EPSG:4326</name> <srs> <number>4326</number> </srs> <extent> <coords> <double>73.45100463600005</double> <double>18.16324718800007</double> <double>134.976797647</double> <double>53.53194315200005</double> </coords> </extent> <scaleDenominators> <double>25000000</double> <double>1000000</double> <double>100000</double> <double>25000</double> </scaleDenominators> <tileHeight>256</tileHeight> <tileWidth>256</tileWidth> </gridSet> </gridSets> <layers> <wmsLayer> <name>china</name> <mimeFormats> <string>image/gif</string> <string>image/jpeg</string> <string>image/png</string> <string>image/png8</string> </mimeFormats> <wmsUrl> <string>http://200.200.200.220:8888/geoserver/wms</string> </wmsUrl> <wmsLayers>geoserver:china</wmsLayers> </wmsLayer> </layers> </gwcConfiguration>
配置好上面的信息之后，进入：
http://localhost:8080/geowebcache/demo ，点击” Reload Configuration
“重新读取配置信息,如下所示：
如果配置信息没错，你会发现，你所配置的图层信息已经显示在这个页面上了，点击 “Seed this layer”，然后你需要输入下面这些信息：
设置好，点submit就开始切图了。在资源管理器中打开，如下图：
配置完成以后，就是如何在地图中显示了，下面是显示的源代码：
<pre name="code" class="html"><html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>china EPSG:4326 image/png</title> <link rel="stylesheet" type="text/css" href="http://200.200.200.220/OpenLayers-2.12/theme/default/style.css"/> <style type="text/css"> body { font-family: sans-serif; font-weight: bold; font-size: .8em; } body { border: 0px; margin: 0px; padding: 0px; } #map { width: 100%; height: 100%; border: 0px; padding: 0px; } </style> <script type="text/javascript" src="http://200.200.200.220/OpenLayers-2.12/OpenLayers.js"></script> <script type="text/javascript" src="http://200.200.200.220/OpenLayers-2.12/lib/OpenLayers/Lang/zh-CN.js"></script> <script type="text/javascript"> var map, demolayer; OpenLayers.DOTS_PER_INCH = 90.71428571428572; OpenLayers.Util.onImageLoadErrorColor = 'transparent'; function init(){ var mapOptions = { resolutions: [0.703125, 0.3515625, 0.17578125, 0.087890625, 0.0439453125, 0.02197265625, 0.010986328125, 0.0054931640625, 0.00274658203125, 0.001373291015625, 6.866455078125E-4, 3.4332275390625E-4, 1.71661376953125E-4, 8.58306884765625E-5, 4.291534423828125E-5, 2.1457672119140625E-5, 1.0728836059570312E-5, 5.364418029785156E-6, 2.682209014892578E-6, 1.341104507446289E-6, 6.705522537231445E-7, 3.3527612686157227E-7 ], projection: new OpenLayers.Projection('EPSG:4326'), maxExtent: new OpenLayers.Bounds(-180.0,-90.0,180.0,90.0), units: "degrees", controls: [] }; map = new OpenLayers.Map('map', mapOptions ); map.addControl(new OpenLayers.Control.PanZoomBar({ position: new OpenLayers.Pixel(2, 15) })); map.addControl(new OpenLayers.Control.Navigation()); map.addControl(new OpenLayers.Control.Scale($('scale'))); map.addControl(new OpenLayers.Control.MousePosition({element: $('location')})); demolayer = new OpenLayers.Layer.WMS( "china","http://200.200.200.220:8080/geowebcache/service/wms", {layers: 'china', format: 'image/png' }, { tileSize: new OpenLayers.Size(256,256)} ); map.addLayer(demolayer); map.zoomToExtent(new OpenLayers.Bounds(73.45100463600005, 18.16324718800007, 134.976797647, 53.53194315200005) ); } </script> </head> <body onLoad="init()"> <div id="map"></div> </body> </html>
显示的结果如下：
转载自：https://blog.csdn.net/leesmn/article/details/48519277
