ArcGIS API for JS 中，三种查询方式

1、QueryTask：这种查询方式只能针对一个图层进行空间或属性查询。返回结果是一个FeatureSet，其中FeatureSet.features[i]加入图层显示。（QueryTask进行查询的地图服务并不必项加载到Map中进行显示。）

QueryTask in 3.22api、Query in 3.22api

例如：

var queryTask = new QueryTask("http://localhost/ArcGIS/rest/services/XX/ZhouShi/MapServer/0");//实例化QueryTask
var query = new Query();//定义Query
//设置Query参数
query.returnGeometry = true;//是否返回几何
query.outFields=["*"],//要查询的字段
query.where = "name = '李'"; //查询条件
queryTask.execute(query, showResults);//回调
function showResults (results) {
var resultCount = results.features.length;
var features = results.features;
for (var i = 0; i < resultCount; i++) {//输出对象编译形式
}
map.centerAndZoom(features[0].geometry,11);
}

2、FindTask：对一个地图服务的多个图层对象（全部或指定几个ID索引）做属性查询。返回的是一个FindResults数组，其中FindResults[i].feature加入图层显示。
FindTask in 3.22api、FindParameters
in 3.22api

例如：
var find = new FindTask("http://localhost/ArcGIS/rest/services/XX/ZhouShi/MapServer");//实例化FindTask
var params = new FindParameters();//定义FindParameters
params.layerIds = [2,3];//设置查询的图层id
params.searchFields = ["STATE_NAME","STATE_FIPS"];//设置查询字段
params.searchText = dom.byId("searchText").value;//设置字段值
find.execute(params, showResults);//回调
function showResults(results) {
var result, attribs;
var s = ["<table border=\"1\"><thead><tr style=\"background-color:#ccc;\"><td>State Name</td><td>FIPS</td><td>Population (1990)</td><td>Population (1999)</td></tr></thead><tbody id=\"states\">"];
dojo.forEach(results,function(result){
attribs = result.feature.attributes;
s.push("<tr><td>" + attribs.STATE_NAME + "</td><td>" + attribs.STATE_FIPS + "</td><td>" + attribs.POP1990 + "</td><td>" + attribs.POP1999 + "</td></tr>");
});
s.push("</tbody></table>");
dojo.byId("tbl").innerHTML = s.join("");
}

3、IdentifyTask：对一个地图服务的多个图层对象（全部或指定几个ID索引）做空间查询。返回一个identifyResults数组，其中identifyResults[i].feature加入图层显示。
IdentifyTask in 3.22api、IdentifyParameters
in 3.22api

例如：

identifyTask = new IdentifyTask(dynamicLayerUrl);//查询
identifyParams = new IdentifyParameters();//查询参数
identifyParams.tolerance = 10;//容差范围
identifyParams.returnGeometry = true;//是否返回图形
identifyParams.layerIds = [ 0 ];//查询图层
identifyParams.layerOption = IdentifyParameters.LAYER_OPTION_VISIBLE;//设置查询的图层
//查询范围
identifyParams.width = map.width;
identifyParams.height = map.height;
identifyParams.geometry = event.mapPoint;
identifyParams.mapExtent = map.extent;
identifyTask.execute(identifyParams,showResults);
function showResults (results) {
var feature;
var sGeometry;
if (results.length > 0) {
for ( var i = 0; i < results.length; i++) {
feature = results[i].feature;
map.infoWindow.set
97df
Title("标注信息");
map.infoWindow.setContent("<span>地区:</span>"
+ feature.attributes.NAME_
+ "<br>"
+ "<span>机构:</span>"
+ feature.attributes.TYPENAME_
+ "<br>"
+ "<span>站点:</span>"
+ feature.attributes.NOTES_
+ "<br>"
+ "<span>地址:</span>"
+ feature.attributes.LOCATION_);
map.infoWindow.show(feature.geometry,map.getInfoWindowAnchor(feature.geometry));
map.infoWindow.show();
}
}
}