delete L.Icon.Default.prototype._getIconUrl
L.Icon.Default.mergeOptions({
iconUrl: require('leaflet/dist/images/marker-icon.png'),
iconRetinaUrl: require('leaflet/dist/images/marker-icon-2x.png'),
shadowUrl: require('leaflet/dist/images/marker-shadow.png')
})来源：https://github.com/Leaflet/Leaflet/issues/4968#issuecomment-269750768