Java实用的DateUtils时间工具类介绍

/**
 * 日期工具类
 * <p>
 *   使用LocalDateTime存取或判断
 * </p>
 */
@Component
public class DateUtils {

  /**
   * 判断两个时间段是否重叠
   * @param slot1
   * @param slot2
   * @return
   */
  public static boolean overlapped(TimeSlot slot1, TimeSlot slot2) {
    TimeSlot previous, next;
    previous = slot1.startTime.isBefore(slot2.startTime) ? slot1 : slot2;
    next = slot2.startTime.isAfter(slot1.startTime) ? slot2 : slot1;
    // 这里业务需要，允许时间点的重叠
    // 例如某个时间段的起始时间：2020-06-29 00:00:00
    // 和另一个时间段的终止时间：2020-06-29 00:00:00
    // 它们俩可以有交点。如果不需要这种逻辑只把le改成lt
    // ，ge改成gt就可
    return !(lt(previous, next) || gt(previous, next));
  }

  /**
   * 上个月的最后一天
   */
  public static String afterMonthLastDay() {
    Calendar c = Calendar.getInstance();
    //当前日期设置为指定日期
    c.setTime(new Date());
    //指定日期月份减去一
    c.add(Calendar.MONTH, -1);
    //指定日期月份减去一后的 最大天数
    c.set(Calendar.DATE, c.getActualMaximum(Calendar.DATE));
    //获取上给月最后一天的日期
    Date lastDateOfPrevMonth = c.getTime();
    java.text.DateFormat formater = new SimpleDateFormat("yyyy-MM-dd");
    return formater.format(lastDateOfPrevMonth);
  }

  /**
   * 构造一个时间段
   * @param startTime
   * @param endTime
   * @return
   */
  public static TimeSlot buildSlot(LocalDateTime startTime, LocalDateTime endTime) {
    return new TimeSlot(startTime, endTime);
  }

  /**
   * less equal
   * 小于等于
   * @param prev
   * @param next
   * @return
   */
  private static boolean le(TimeSlot prev, TimeSlot next) {
    return lt(prev, next) || next.endTime.isEqual(prev.startTime);
  }

  /**
   * greater equal
   * 大于等于
   * @param prev
   * @param next
   * @return
   */
  private static boolean ge(TimeSlot prev, TimeSlot next) {
    return gt(prev, next) || prev.endTime.isEqual(next.startTime);
  }

  /**
   * greater than
   * 大于
   * @param prev
   * @param next
   * @return
   */
  private static boolean gt(TimeSlot prev, TimeSlot next) {
    return prev.endTime.isBefore(next.startTime);
  }

  /**
   * less than
   * 小于
   * @param prev
   * @param next
   * @return
   */
  private static boolean lt(TimeSlot prev, TimeSlot next) {
    return next.endTime.isBefore(prev.startTime);
  }


  /**
   * 将单元格数据转换为日期样式的字符串
   *
   * @param cell
   * @return
   */
  public static String convertDate(Cell cell) {
    String value = "";
    if (cell.getCellType() == CellType.NUMERIC) {
      if (HSSFDateUtil.isCellDateFormatted(cell)) {
        //用于转化为日期格式
        Date d = cell.getDateCellValue();
        java.text.DateFormat formater = new SimpleDateFormat("yyyy-MM-dd");
        value = formater.format(d);
      }
    }
    return value;
  }

  /**
   * 将单元格数据转换为日期样式的字符串
   *
   * @param cell
   * @return
   */
  public static String convertString(Cell cell) {
    String value = "";
    if (cell.getCellType() == CellType.STRING) {
      value = cell.getStringCellValue();
    }
    return value;
  }

  /**
   * 将单元格数据转换为金额样式的字符串
   * @author:xhmaca
   * @param cell
   * @return
   */
  public static String convertBigDecimal(Cell cell) {
    String value = "";
    if (cell.getCellType() == CellType.NUMERIC) {
      if (HSSFDateUtil.isCellDateFormatted(cell)) {

      } else {
        BigDecimal bigDecimal = new BigDecimal(cell.getNumericCellValue());
        value = bigDecimal.toString();
      }
    }
    return value;
  }

  /**
   * 计算字符型日期天数差
   * @param dateStart
   * @param dateStop
   */
  public static Integer dateDifferent(String dateStart, String dateStop) {
    long diff,diffSeconds,diffMinutes,diffHours,diffDays = 0;
    SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
    try {
      Date d1 = format.parse(dateStart);//毫秒ms
      Date d2 = format.parse(dateStop);//毫秒ms
      diff = d2.getTime() - d1.getTime();
      diffSeconds = diff / 1000 % 60;
      diffMinutes = diff / (60 * 1000) % 60;
      diffHours = diff / (60 * 60 * 1000) % 24;
      diffDays = diff / (24 * 60 * 60 * 1000);
      System.out.print("两个时间相差:");
      System.out.print(diffDays + "天,");
      System.out.print(diffHours + "小时,");
      System.out.print(diffMinutes + "分钟,");
      System.out.print(diffSeconds + "秒.");
    } catch (ParseException e) {
      e.printStackTrace();
    }
    int days = (int) diffDays;
    return days;
  }

  /**
   * 计算字符型日期天数差
   * @param dateStart
   * @param dateStop
   */
  public static long datelongDifferent(String dateStart, String dateStop) {
    long diff,diffSeconds,diffMinutes,diffHours,diffDays = 0;
    SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
    try {
      Date d1 = format.parse(dateStart);//毫秒ms
      Date d2 = format.parse(dateStop);//毫秒ms
      diff = d2.getTime() - d1.getTime();
      diffSeconds = diff / 1000 % 60;
      diffMinutes = diff / (60 * 1000) % 60;
      diffHours = diff / (60 * 60 * 1000) % 24;
      diffDays = diff / (24 * 60 * 60 * 1000);
      System.out.print("两个时间相差:");
      System.out.print(diffDays + "天,");
      System.out.print(diffHours + "小时,");
      System.out.print(diffMinutes + "分钟,");
      System.out.print(diffSeconds + "秒.");
    } catch (ParseException e) {
      e.printStackTrace();
    }
    return diffDays;
  }

  /**
   * 获取当前日期
   */
  public static String getCurrectDate()
  {
    SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");
    Date date = new Date();//当前日期
    return df.format(date);
  }

  /**
   * 获取当前日期
   */
  public static String getLongFormatDate(String date)
  {
    SimpleDateFormat df1 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    return df1.format(date);
  }

  /**
   * 获取当前日期
   */
  public static String getShortFormatDate(String date)
  {
    SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");
    return df.format(date);
  }

  /**
   * 计算年份
   * @param dateStart
   *
   */
  public static Integer getYear(String dateStart) {
    long diff,diffSeconds,diffMinutes,diffHours,diffDays = 0;
    SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
    try {
      Date d1 = format.parse(dateStart);//毫秒ms
      return d1.getYear()+1900;

    } catch (ParseException e) {
      e.printStackTrace();
    }
    return 0;
  }

  /**
   * 时间段类
   */
  static class TimeSlot{
    private LocalDateTime startTime;
    private LocalDateTime endTime;

    public TimeSlot(LocalDateTime startTime, LocalDateTime endTime) {
      if (startTime.isAfter(endTime)) {
        this.startTime = endTime;
        this.endTime = startTime;
      } else {
        this.startTime = startTime;
        this.endTime = endTime;
      }
    }

  }
}