1 public static void main(String[] args) { 2 EmployDO zhangsan = new EmployDO.Builder().name("張三").sex("男").position("職員").status("在職").age("20").build(); 3 EmployDO lisi = new EmployDO.Builder().name("李四").sex("男").position("職員").status("在職").age("24").build(); 4 EmployDO wangwu = new EmployDO.Builder().name("王五").sex("男").position("職員").status("離職").age("21").build(); 5 EmployDO yangliu = new EmployDO.Builder().name("楊六").sex("男").position("職員").status("在職").age("25").build(); 6 EmployDO lihua = new EmployDO.Builder().name("李華").sex("女").position("領導").status("在職").age("20").build(); 7 EmployDO xiaohua = new EmployDO.Builder().name("小花").sex("女").position("職員").status("離職").age("23").build(); 8 EmployDO xiaofeng = new EmployDO.Builder().name("小鳳").sex("女").position("領導").status("在職").age("25").build(); 9 List<EmployDO> employDOS = Arrays.asList(zhangsan, lisi, wangwu, yangliu, lihua, xiaohua, xiaofeng); 10 // 根據sex分組 11 Map<String, List<EmployDO>> map = employDOS.stream().collect(Collectors.groupingBy(EmployDO::getSex)); 12 System.out.println(JSON.toJSONString(map)); 13 // 根據sex分組,計算出每個小組的人數 14 Map<String, Long> countMap = employDOS.stream().collect(Collectors.groupingBy(employ -> employ.getSex(), Collectors.counting())); 15 System.out.println(JSON.toJSONString(countMap)); 16 }
輸出 :
map輸出:
{"女":[{"age":"20","name":"李華","position":"領導","sex":"女","status":"在職"},{"age":"23","name":"小花","position":"職員","sex":"女","status":"離職"},{"age":"25","name":"小鳳","position":"領導","sex":"女","status":"在職"}],"男":[{"age":"20","name":"張三","position":"職員","sex":"男","status":"在職"},{"age":"24","name":"李四","position":"職員","sex":"男","status":"在職"},{"age":"21","name":"王五","position":"職員","sex":"男","status":"離職"},{"age":"25","name":"楊六","position":"職員","sex":"男","status":"在職"}]}
countMap輸出:
{"女":3,"男":4}