java获取一个时间段内的所有年份/月份/天

朱雀 2022-10-06 00:54 379阅读 0赞

代码示例：

/**
         * 枚举类
         */
    	public enum DateUnit {
            YEAR("year"),
            MONTH("month"),
            DAY("day");
    
            private String unit;
    
            DateUnit(String unit) {
                this.unit = unit;
            }
    
            public String getUnit() {
                return this.unit;
            }
        }
    
        /**
         * 获取两个日期字符串之间的所有年份/月份/天（左闭右闭）
         * 
         * @param startDateStr  yyyyMMdd
         * @param endDateStr    yyyyMMdd
         * @param dateUnit
         * @return
         */
        public static List<String> getDateStrBetween(String startDateStr, String endDateStr, DateUnit dateUnit) {
            List<String> result = new ArrayList<>();
            SimpleDateFormat sdf;
            Calendar start = Calendar.getInstance();
            Calendar end = Calendar.getInstance();
    
            try {
                sdf = new SimpleDateFormat("yyyyMMdd");
                start.setTime(sdf.parse(startDateStr));
                end.setTime(sdf.parse(endDateStr));
    //            end.add(Calendar.DAY_OF_MONTH,-1); // end往前减1天，处理20210101这种情况（实现左闭右开）
            } catch (ParseException e) {
                e.printStackTrace();
            }
    
            Calendar curr = start;
    
            switch (dateUnit) {
                case YEAR:
                    sdf = new SimpleDateFormat("yyyy");
                    while (curr.before(end)) {
                        result.add(sdf.format(curr.getTime()));
                        curr.add(Calendar.YEAR, 1);
                    }
                    break;
                case MONTH:
                    sdf = new SimpleDateFormat("yyyyMM");
                    while (curr.before(end)) {
                        result.add(sdf.format(curr.getTime()));
                        curr.add(Calendar.MONTH, 1);
                    }
                    break;
                case DAY:
                    sdf = new SimpleDateFormat("yyyyMMdd");
                    while (curr.before(end)) {
                        result.add(sdf.format(curr.getTime()));
                        curr.add(Calendar.DAY_OF_MONTH, 1);
                    }
                    break;
                default:
                    sdf = new SimpleDateFormat("yyyy");
                    while (curr.before(end)) {
                        result.add(sdf.format(curr.getTime()));
                        curr.add(Calendar.YEAR, 1);
                    }
                    break;
            }
    
            // 最后要加上 endDateStr 所属的年份/月份/天（保证不漏）
            result.add(sdf.format(end.getTime()));
            return result.stream().distinct().collect(Collectors.toList());
        }