（二一）ArcGIS JS QueryTask查询图层所有数据

系统管理员 2021-09-17 07:56 798阅读 0赞

### 前言 ###

之前写过一次不通过查询、通过featureLayer来获取图层中所有数据，详见 [https://blog.csdn.net/idomyway/article/details/84591687，][https_blog.csdn.net_idomyway_article_details_84591687]  
    不过，经过实践，通过featureLayer来获取图层中所有数据有以下局限性：

1.  发现只能在map地图中的update-end事件完成后才可以获取到要素
2.  无法获取完整的field信息

我们也可以通过queryTask完成获取图层中完整数据，获取的数据结构如下：  
![在这里插入图片描述][20181210185102657.png]

**注意**：server服务器查询默认返回的最大数是`1000`，在超过1000的时候我们需要手动调节：  
    [https://blog.csdn.net/idomyway/article/details/78630646][https_blog.csdn.net_idomyway_article_details_78630646]

### 实现代码 ###

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
        <link rel="stylesheet" href="https://js.arcgis.com/3.26/esri/css/esri.css">
        <script src="https://js.arcgis.com/3.26/"></script>
        <style>
            html,
            body,
            #map {
                height: 100%;
                width: 100%;
                margin: 0;
                padding: 0;
            }
        </style>
    </head>
    <body>
        <div id="map"></div>
        <script>
            require([
                "esri/map",
                "esri/layers/ArcGISDynamicMapServiceLayer",
                "esri/tasks/QueryTask",
                "esri/tasks/query",
                "dojo/domReady!"
            ], function (
                Map,
                ArcGISDynamicMapServiceLayer,
                QueryTask,
                Query
            ) {
                var map = new Map("map");
                var layer = new ArcGISDynamicMapServiceLayer("http://localhost:6080/arcgis/rest/services/wfMap/cgstreetDZTiled/MapServer");
                map.addLayer(layer);
    
                var query=new Query();
                query.outFields = ["*"];
                query.where = "1=1";
                query.returnGeometry = true;
                //实例化查询对象
                var queryTask = new QueryTask("http://localhost:6080/arcgis/rest/services/wfMap/cgstreetDZTiled/MapServer/0");
                //进行查询
                queryTask.execute(query,showFindResult);
                function showFindResult(result) {
                    console.log(result);
                }
            });
        </script>
    </body>
    </html>

[https_blog.csdn.net_idomyway_article_details_84591687]: https://blog.csdn.net/idomyway/article/details/84591687%EF%BC%8C
[20181210185102657.png]: /images/20210726/bc5caf8c2cc64be2b9d2c0a12d0688a7.png
[https_blog.csdn.net_idomyway_article_details_78630646]: https://blog.csdn.net/idomyway/article/details/78630646