Vector Wfs

<!--
  示例：OpenLayers WFS 边界框加载
  要点：VectorSource 的 url 函数按 bbox 返回 data: 地址，GeoJSON 即时解析入库
  依赖：OpenLayers 10.3.1 · jsDelivr CDN
-->
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta name="robots" content="noindex,follow">
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>WFS 边界框加载</title>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/ol@10.3.1/ol.css">
<style>
  html,body{height:100%;margin:0}
  body{display:flex;flex-direction:column;overflow:hidden;
       font:13px/1.6 -apple-system,"Segoe UI","PingFang SC",sans-serif}
  .bar{flex:0 0 auto;padding:8px 12px;background:#f6f7f9;border-bottom:1px solid #e3e6ea;
       display:flex;gap:10px;align-items:center;flex-wrap:wrap;font-size:12px;color:#58606e}
  .bar label{display:flex;gap:5px;align-items:center;cursor:pointer}
  .bar select,.bar input[type=range]{font-size:12px}
  .bar .val{font-family:ui-monospace,Consolas,monospace;color:#1f5fd0;min-width:44px}
  .bar .sep{width:1px;height:16px;background:#d8dce2}
  #map{flex:1 1 auto;min-height:0;background:#eef0f3}
</style>
</head>
<body>
<div class="bar">
  <span>WFS bbox 请求（页面内应答）</span>
  <span class="sep"></span>
  <span id="info">要素 0</span>
</div>
<div id="map"></div>
<script src="https://cdn.jsdelivr.net/npm/ol@10.3.1/dist/ol.js"></script>
<script>
(function () {
  'use strict';

  if (typeof ol === 'undefined') {
    document.getElementById('map').textContent = 'OpenLayers 加载失败，请检查能否访问 cdn.jsdelivr.net';
    return;
  }


  var lakes = [
    {name: '昆明湖', ring: [[116.255, 39.985], [116.285, 39.985], [116.285, 40.005], [116.255, 40.005]]},
    {name: '玉渊潭', ring: [[116.305, 39.915], [116.330, 39.915], [116.330, 39.930], [116.305, 39.930]]},
    {name: '北海', ring: [[116.375, 39.922], [116.392, 39.922], [116.392, 39.935], [116.375, 39.935]]},
    {name: '朝阳公园湖', ring: [[116.470, 39.935], [116.490, 39.935], [116.490, 39.948], [116.470, 39.948]]},
    {name: '南海子', ring: [[116.420, 39.760], [116.455, 39.760], [116.455, 39.785], [116.420, 39.785]]}
  ];

  var vectorSource = new ol.source.Vector({
    format: new ol.format.GeoJSON(),
    strategy: ol.loadingstrategy.bbox,
    url: function (extent) {
      var geographic = ol.proj.transformExtent(extent, 'EPSG:3857', 'EPSG:4326');
      var features = lakes.filter(function (lake) {
        var b = lake.ring;
        return !(b[0][0] > geographic[2] || b[1][0] < geographic[0] ||
          b[0][1] > geographic[3] || b[2][1] < geographic[1]);
      }).map(function (lake) {
        var ring = lake.ring.concat([lake.ring[0]]);
        return {
          type: 'Feature',
          properties: {name: lake.name, layer: 'demo:water'},
          geometry: {type: 'Polygon', coordinates: [ring]}
        };
      });
      return 'data:application/json;charset=utf-8,' + encodeURIComponent(
        JSON.stringify({type: 'FeatureCollection', features: features})
      );
    }
  });

  var vector = new ol.layer.Vector({
    source: vectorSource,
    style: new ol.style.Style({
      fill: new ol.style.Fill({color: 'rgba(64, 140, 210, 0.35)'}),
      stroke: new ol.style.Stroke({color: 'rgba(20, 90, 160, 0.9)', width: 2}),
      text: new ol.style.Text({
        text: '',
        font: '11px sans-serif'
      })
    })
  });

  vector.setStyle(function (feature) {
    return new ol.style.Style({
      fill: new ol.style.Fill({color: 'rgba(64, 140, 210, 0.35)'}),
      stroke: new ol.style.Stroke({color: 'rgba(20, 90, 160, 0.9)', width: 2}),
      text: new ol.style.Text({
        text: feature.get('name'),
        font: '500 11px sans-serif',
        fill: new ol.style.Fill({color: '#0b3d68'}),
        stroke: new ol.style.Stroke({color: '#ffffff', width: 3})
      })
    });
  });

  var map = new ol.Map({
    target: 'map',
    layers: [
      new ol.layer.Tile({source: new ol.source.XYZ({url: 'https://server.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer/tile/{z}/{y}/{x}', attributions: 'Tiles © Esri'}), opacity: 0.7}),
      vector
    ],
    view: new ol.View({
      center: ol.proj.fromLonLat([116.370, 39.910]),
      zoom: 11
    })
  });

  function updateCount() {
    document.getElementById('info').textContent =
      '要素 ' + vectorSource.getFeatures().length;
  }

  vectorSource.on('featuresloadend', updateCount);
  vectorSource.on('changefeature', updateCount);
  updateCount();

})();
</script>
</body>
</html>