Java 对list集合指定字段进行排序

￡神魔★判官ぃ 2022-12-22 08:53 200阅读 0赞

> 使用Java8流和list.sort 两种方式，经简单测试，2个方式的时间差异不大

private List<Map<String, Object>> getListMaps() {
            List<Map<String, Object>> htMachineAccountList = new ArrayList<>();
    
            Map<String, Object> map1 = new HashMap<>();
            map1.put("FDQ_DEF_001", Timestamp.valueOf(LocalDateTime.of(LocalDate.of(2020, 1, 2), LocalTime.ofNanoOfDay(0))));
            map1.put("FJD_DEF_001", 3.6);
            map1.put("FHT_DEF_002", 111);
            htMachineAccountList.add(map1);
            Map<String, Object> map2 = new HashMap<>();
            map2.put("FDQ_DEF_001", Timestamp.valueOf(LocalDateTime.of(LocalDate.of(2020, 1, 8), LocalTime.ofNanoOfDay(0))));
            map2.put("FJD_DEF_001", 8.2);
            map2.put("FHT_DEF_002", 222);
            htMachineAccountList.add(map2);
            for (int i = 0; i < 10000000; i++) {
                Map<String, Object> map3 = new HashMap<>();
                map3.put("FDQ_DEF_001", Timestamp.valueOf(LocalDateTime.of(LocalDate.of(2020, 1, 5), LocalTime.ofNanoOfDay(0))));
                map3.put("FJD_DEF_001", i);
                map3.put("FHT_DEF_002", 333);
                htMachineAccountList.add(map3);
            }
            return htMachineAccountList;
        }
    
        @Test
        public void testList01() {
            long l1 = System.currentTimeMillis();
            //到期日  FDQ_DEF_001 》  顺序号	FJD_DEF_001 》 编号 FHT_DEF_002
            List<Map<String, Object>> htMachineAccountList = getListMaps();
            List<Map<String, Object>> collect = htMachineAccountList.stream().sorted((o1, o2) -> {
                Timestamp fdqDef001 = (Timestamp) o1.get("FDQ_DEF_001");
                Timestamp fdqDef002 = (Timestamp) o2.get("FDQ_DEF_001");
                if (fdqDef001.compareTo(fdqDef002) > 0) {
                    return 1;
                } else if (fdqDef001.compareTo(fdqDef002) < 0) {
                    return -1;
                } else if (fdqDef001.compareTo(fdqDef002) == 0) {
                    String fjdDef001 = o1.get("FJD_DEF_001").toString();
                    String fjdDef002 = o2.get("FJD_DEF_001").toString();
                    if (fjdDef001.compareTo(fjdDef002) > 0) {
                        return 1;
                    } else if (fjdDef001.compareTo(fjdDef002) < 0) {
                        return -1;
                    } else if (fjdDef001.compareTo(fjdDef002) == 0) {
                        String def002 = o1.get("FHT_DEF_002").toString();
                        String def003 = o2.get("FHT_DEF_002").toString();
                        if (def002.compareTo(def003) > 0) {
                            return 1;
                        } else if (def002.compareTo(def003) < 0) {
                            return -1;
                        } else {
                            return 1;
                        }
                    }
                }
                return 0;
            }).collect(Collectors.toList());
    //        for (Map<String, Object> map : collect) {
    //            map.forEach((k, v) -> {
    //                System.out.print(" " + v + "  ");
    //            });
    //            System.out.println();
    //        }
            long l2 = System.currentTimeMillis();
            System.out.println((l2-l1)/1000);
        }
    
    
        @Test
        public void testListSort02() {
            long l1 = System.currentTimeMillis();
            //到期日  FDQ_DEF_001 》  顺序号	FJD_DEF_001 》 编号 FHT_DEF_002
            List<Map<String, Object>> htMachineAccountList = getListMaps();
    
            htMachineAccountList.sort((o1, o2) -> {
                Timestamp fdqDef001 = (Timestamp) o1.get("FDQ_DEF_001");
                Timestamp fdqDef002 = (Timestamp) o2.get("FDQ_DEF_001");
                if (fdqDef001.compareTo(fdqDef002) > 0) {
                    return 1;
                } else if (fdqDef001.compareTo(fdqDef002) < 0) {
                    return -1;
                } else if (fdqDef001.compareTo(fdqDef002) == 0) {
                    String fjdDef001 = o1.get("FJD_DEF_001").toString();
                    String fjdDef002 = o2.get("FJD_DEF_001").toString();
                    if (fjdDef001.compareTo(fjdDef002) > 0) {
                        return 1;
                    } else if (fjdDef001.compareTo(fjdDef002) < 0) {
                        return -1;
                    } else if (fjdDef001.compareTo(fjdDef002) == 0) {
                        String def002 = o1.get("FHT_DEF_002").toString();
                        String def003 = o2.get("FHT_DEF_002").toString();
                        if (def002.compareTo(def003) > 0) {
                            return 1;
                        } else if (def002.compareTo(def003) < 0) {
                            return -1;
                        } else {
                            return 1;
                        }
                    }
                }
                return 0;
            });
    
    //        for (Map<String, Object> map : htMachineAccountList) {
    //            map.forEach((k, v) -> {
    //                System.out.print(" " + v + "  ");
    //            });
    //            System.out.println();
    //        }
            long l2 = System.currentTimeMillis();
            System.out.println((l2-l1)/1000);
        }