stream 分组
2022/1/8 23:04:48
本文主要是介绍stream 分组,对大家解决编程问题具有一定的参考价值,需要的程序猿们随着小编来一起学习吧!
@Data public class MiddleFloorDto { private Long middleId; private Long floorId; private Long landingpageId; }
public class Main { public static void main(String[] args) { ArrayList<MiddleFloorDto> list = new ArrayList<>(); MiddleFloorDto dto1 = new MiddleFloorDto(); dto1.setFloorId(1l); dto1.setLandingpageId(1l); MiddleFloorDto dto2 = new MiddleFloorDto(); dto2.setFloorId(12l); dto2.setLandingpageId(2l); MiddleFloorDto dto3 = new MiddleFloorDto(); dto3.setFloorId(8l); dto3.setLandingpageId(2l); MiddleFloorDto dto4 = new MiddleFloorDto(); dto4.setMiddleId(2l); dto4.setLandingpageId(3l); MiddleFloorDto dto5 = new MiddleFloorDto(); dto5.setFloorId(2l); dto5.setLandingpageId(4l); MiddleFloorDto dto6 = new MiddleFloorDto(); dto6.setFloorId(4l); dto6.setLandingpageId(2l); MiddleFloorDto dto7 = new MiddleFloorDto(); dto7.setFloorId(6l); dto7.setLandingpageId(2l); list.add(dto7); list.add(dto6); list.add(dto5); list.add(dto4); list.add(dto3); list.add(dto2); list.add(dto1); Map<Long, List<MiddleFloorDto>> collect = list.stream().collect(Collectors.groupingBy(MiddleFloorDto::getLandingpageId)); System.out.println(collect.get(1l)); System.out.println(collect.get(2l)); System.out.println(collect.get(3l)); System.out.println(collect.get(4l)); System.out.println(collect.get(5l)); System.out.println(collect.get(6l)); }
/* [MiddleFloorDto{middleId=null, floorId=1, landingpageId=1}] [MiddleFloorDto{middleId=null, floorId=6, landingpageId=2}, MiddleFloorDto{middleId=null, floorId=4, landingpageId=2}, MiddleFloorDto{middleId=null, floorId=8, landingpageId=2}, MiddleFloorDto{middleId=null, floorId=12, landingpageId=2}] [MiddleFloorDto{middleId=2, floorId=null, landingpageId=3}] [MiddleFloorDto{middleId=null, floorId=2, landingpageId=4}] null null*/ 测试结果符合预期。
这篇关于stream 分组的文章就介绍到这儿,希望我们推荐的文章对大家有所帮助,也希望大家多多支持为之网!
- 2024-10-01基于Python+Vue开发的医院门诊预约挂号系统
- 2024-10-01基于Python+Vue开发的旅游景区管理系统
- 2024-10-01RestfulAPI入门指南:打造简单易懂的API接口
- 2024-10-01初学者指南:了解和使用Server Action
- 2024-10-01Server Component入门指南:搭建与配置详解
- 2024-10-01React 中使用 useRequest 实现数据请求
- 2024-10-01使用 golang 将ETH账户的资产平均分散到其他账户
- 2024-10-01JWT用户校验课程:从入门到实践
- 2024-10-01Server Component课程入门指南
- 2024-09-30Dnd-Kit学习:新手快速入门指南