项目后续-日常应用代码记录

Posted 2021-02-21 xxxhstar

一、代码实现

1.数组转换成List

String[] deviceIdAy = buildingDto.getChannelId().split(Symbol.COMMA);
//设备id
List<String> deviceIdList = Arrays.asList(deviceIdAy);

2.List转换成数组

List<String> gatemateIdList = buildingDao.listBuildingDeviceId(buildingDeviceCond);
String[] deviceIdAy = gatemateIdList.toArray(new String[gatemateIdList.size()]);

3.List数组拼接到另外一个List后面（channelDtoListTo放到channelDtoList后面）

List<ChannelDTO> channelDtoListTo = buildingDao.listChannel(channelCondTo);
channelDtoListTo.stream().sequential().collect(Collectors.toCollection(() -> channelDtoList));

3.List的stream的用法

1.map 用来对list中的单独对象进行全体修改然后返回一个list回来

Set<String> roleList = roles.stream().map(role -> "ROLE_" + role.toUpperCase()).collect(Collectors.toSet());

1.filter 用来过滤符合条件的数据，然后返回一个list

selfStudyClassroomDtoList = selfStudyClassroomDtoList.stream().filter(s -> s.getWeekDay().equals(w)).collect(Collectors.toList());