JDK8 LAMP表达式常用

List转为Map写法

List list01 = new ArrayList()<>;
Maplist01.stream().collect(Collectors.toMap(User::getId, Function.identity(), (key1, key2) -> key2));

List根据条件过滤筛选

List userListNew = userList.stream().filter(s-> s.getStatus()==3||s.getStatus()==4||s.getStatus()==5).collect(Collectors.toList());