🍀JavaSE：Stream流

list -> map

Map<Integer, T> webGisUserMap = list.stream().collect(Collectors.toMap(T::getFiled, v -> v, (k1, k2) -> k1));

list -> string

 String str = list.stream().map(T::getFiled).map(String::valueOf).collect(Collectors.joining(","));

string -> list

List<Integer> list = Arrays.stream(str.split(",")).map(Integer::valueOf).collect(Collectors.toList());

list对象 -> list对象

List<Integer> vehicleIdList = list.stream().map(T::getFiled).collect(Collectors.toList());

根据条件过滤

List<Integer> idSet = list.stream().filter(item -> !list2.contains(item)).collect(toList());