List＜Map＜String,Object＞＞ 转 Map＜String,String＞ 某一列值得转换，分组

List<Map<String,Object>> 类型转换map，分组

List<Map<String,Object>> list = cameraService.findCamerByType(“1”);
Map<String,List<Map<String,Object>>> maps = list.stream().collect(Collectors.groupingBy(map->map.get(“position”).toString()));