在OpenLayers中通过过滤器设置GeoJSON样式

var vectorSource = new ol.source.Vector({
  url: 'path/to/geojson.json',
  format: new ol.format.GeoJSON()
});

var vectorLayer = new ol.layer.Vector({
  source: vectorSource
});

function styleFunction(feature) {
  var category = feature.get('category');
  var style;
  if (category === 'A') {
    style = new ol.style.Style({
      fill: new ol.style.Fill({
        color: 'blue'
      }),
      stroke: new ol.style.Stroke({
        color: 'black',
        width: 2
      })
    });
  } else if (category === 'B') {
    style = new ol.style.Style({
      fill: new ol.style.Fill({
        color: 'green'
      }),
      stroke: new ol.style.Stroke({
        color: 'black',
        width: 2
      })
    });
  }
  return style;
}

vectorLayer.setStyle(styleFunction);