基于OpenLayers 的WFS模糊查询优化

思路：先通过指定一个featureName字段，在全表查询时，返回的数据就会比较小，这样会提高一些速度。返回数据中，我们取出featureid的值，再通过url进行GML格式的解析，从而得到查询后返回的全字段GML信息。

实现代码：

var filter = new OpenLayers.Filter.Logical({
type: OpenLayers.Filter.Logical.AND,
filters: [
new OpenLayers.Filter.Spatial({
type: OpenLayers.Filter.Spatial.INTERSECTS, //INTERSECTS, //相交OK
value: gemetry,
projection: "EPSG:4326"
}),
new OpenLayers.Filter.Comparison({//比较操作符
type: OpenLayers.Filter.Comparison.LIKE,
property: "cite:TDZL",
value: "*"+str+"*"
})
]
});
var filter_1_0 = new OpenLayers.Format.Filter.v1_0_0();
var xml = new OpenLayers.Format.XML();
var xmlPara = "<?xml version='1.0' encoding='UTF-8'?>"
+ "<wfs:GetFeature service='WFS' version='1.0.0' "
+ "xmlns:wfs='http://www.opengis.net/wfs' "
+ "xmlns:gml='http://www.opengis.net/gml' "
+ "xmlns:ogc='http://www.opengis.net/ogc' "
+ "xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' "
+ "xsi:schemaLocation='http://www.opengis.net/wfs http://schemas.opengis.net/wfs/1.0.0/wfs.xsd'>" + "<wfs:Query typeName='cite:tz_zd_WGS84' srsName='EPSG:4326' >"
+"<wfs:PropertyName>cite:TDZL</wfs:PropertyName>"
+ xml.write(filter_1_0.write(filter))
+ "</wfs:Query>"
+ "</wfs:GetFeature>";

var request = OpenLayers.Request.POST( {
url : "http://localhost:8080/geoserver/wfs?",
data : xmlPara,
callback : handler
});

}
function handler(req){
var xmlDoc = req.responseXML;
str= text.value;
theNodes = xmlDoc.getElementsByTagName("cite:TDZL");
fid = xmlDoc.getElementsByTagName("cite:tz_zd_WGS84");
if(theNodes[0]==null){alert("未查到信息")}
for (i=0;i < theNodes.length; i++ ){
var fullName=theNodes[i].childNodes[0].nodeValue;
if (fullName.indexOf(str) > -1 ){
var x = fid[i].attributes;
var gml = "http://localhost:8080/geoserver/ows?service=WFS&version=1.0.0&request=GetFeature&typeName=cite:tz_zd_WGS84&featureid=" +x.getNamedItem("fid").nodeValue;
OpenLayers.loadURL(gml,'', this, caller);
selectArea = new OpenLayers.Layer.GML("GML",gml,{style:{fillColor: "green"}});
map.addLayer(selectArea);

}

}
}
function caller(data){
g =  new OpenLayers.Format.GML();
features = g.read(data.responseText);
var result;
result ="<br>"
result += "<ul><li><b>公司名: <\/b>"+features[0].attributes.QLR+"<\/li><\/ul>";
result +="<ul><li><b>地名: <\/b>"+features[0].attributes.TDZL+"<\/li><\/ul>";
result +="<ul><li><b>用地类型: <\/b>"+features[0].attributes.BZ+"<\/li><\/ul>";
result +="<ul><li><b>面积: <\/b>"+features[0].attributes.SHAPE_Area+"<\/li><\/ul>";;
document.getElementById("result").innerHTML =result;
point = features[0].geometry.getCentroid()
map.setCenter(new OpenLayers.LonLat(point.x, point.y),15);
}

这样，测试一个城市数据返回数据的时间控制在3秒内，符合实际需求。