iserver发布的shapefile服务，defaultstyle.json无法根据字段进行分值渲染，设置如下line_color的时候，图层服务报错
{ "layout": { "visibility": "visible", "line-cap": "round", "line-join": "round" }, "maxzoom": 18, "paint": { "line-width": 2.4, "line-color": [ "case", ["==", ["get", "line_code"], "st_15"], "#c8b38e", ["==", ["get", "line_code"], "st_18"], "#C09453" ] }, "id": "line_axises", "source": "2d_lines", "source-layer": "line_axises@line_axises", "type": "line", "minzoom": 0 },
