Java中的日期处理

获取系统日期时间，数据返回类型：Date

import java.util.Date;

public class DateUtils{

  public static Date getNowDate() {

      return new Date();
  }

}

字符串日期时间转换成Date类型的日期时间，数据返回类型：Date

import java.util.Date;

public class DateUtils{

  public static Date getDateTime(String dateTime) {
       
      SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
      Date Date = new Date();
      try {
          Date = sdf.parse(dateTime);
      } catch (ParseException e) {
          e.printStackTrace();
      }
      return Date;
  }

}

获取系统日期时间，数据返回类型：Date

import java.util.Date;
import java.time.LocalDateTime;
import java.time.ZoneId;

public class DateUtils{

  public static Date getCurrentDate() {
        
      return Date.from(LocalDateTime.now().atZone(ZoneId.systemDefault()).toInstant());
  }

}

获取系统日期时间，数据返回类型：LocalDateTime

import java.time.LocalDateTime;

public class DateUtils{

  public static LocalDateTime getCurrentLocalDateTime() {
      
      return LocalDateTime.now();
  }

}

获取日期文件路径，即：年/月/日，如：2018/08/08，数据返回类型：String

import java.util.Date;
import org.apache.commons.lang3.time.DateFormatUtils;

public class DateUtils{

  public static final String getDatePath() {

      return DateFormatUtils.format(new Date(), "yyyy/MM/dd");
  }

}

获取系统日期时间，字符串格式：年-月-日，如：2018-08-08，数据返回类型：String

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

public class DateUtils{

  public final static String DATE_PATTERN = "yyyy-MM-dd";

  public static String getCurrentYMD() {
        
      return LocalDateTime.now().format(DateTimeFormatter.ofPattern(DATE_PATTERN));
  }

}

获取系统日期时间，字符串格式：年-月-日 时:分:秒，如：2018-08-08 08:08:08，数据返回类型：String

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

public class DateUtils{

  public final static String DATE_TIME_PATTERN = "yyyy-MM-dd HH:mm:ss";

  public static String getCurrentYMDHMS() {
        
      return LocalDateTime.now().format(DateTimeFormatter.ofPattern(DATE_TIME_PATTERN));
  }

}

获取系统日期时间，字符串格式：年月日时分秒毫秒，如：20180808080808888，数据返回类型：String

import java.util.Calendar;

public class DateUtils{

  public static String getDateTimeStr() {
        
      Calendar Cld = Calendar.getInstance();
      int YY = Cld.get(Calendar.YEAR);
      String MM = Cld.get(Calendar.MONTH) + 1 + "";
      if (Cld.get(Calendar.MONTH) + 1 < 10) {
          MM = "0" + MM;
      }
      String DD = Cld.get(Calendar.DATE) + "";
      if (Cld.get(Calendar.DATE) < 10) {
          DD = "0" + DD;
      }
      String HH = Cld.get(Calendar.HOUR_OF_DAY) + "";
      if (Cld.get(Calendar.HOUR_OF_DAY) < 10) {
          HH = "0" + HH;
      }
      String mm = Cld.get(Calendar.MINUTE) + "";
      if (Cld.get(Calendar.MINUTE) < 10) {
          mm = "0" + mm;
      }
      String SS = Cld.get(Calendar.SECOND) + "";
      if (Cld.get(Calendar.SECOND) < 10) {
          SS = "0" + SS;
      }
      int MI = Cld.get(Calendar.MILLISECOND);
      return YY + MM + DD + HH + mm + SS + MI;
  }

}

获取上个月最后一天的最后一秒，数据返回类型：Date

import java.util.Calendar;

public class DateUtils{

  public static Date getLastMonthLastDay() {

      Calendar calendar = Calendar.getInstance();
      int month = calendar.get(Calendar.MONTH);
      calendar.set(Calendar.MONTH, month - 1);
      calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
      calendar.set(Calendar.HOUR_OF_DAY, calendar.getActualMaximum(Calendar.HOUR_OF_DAY));
      calendar.set(Calendar.MINUTE, calendar.getActualMaximum(Calendar.MINUTE));
      calendar.set(Calendar.SECOND, calendar.getActualMaximum(Calendar.SECOND));
      return calendar.getTime();
  }

}

计算两个时间的时间差（向上取整，单位：天），数据返回类型：int

import java.util.Date;

public class DateUtils{

  public static int getDiffDays(Date yesterday, Date today) {
      
      if (yesterday == null || today== null) {
          throw new NullPointerException("by calculating the difference between two [java.util.Date]");
      }
      double yDouble = today.getTime() - yesterday.getTime();
      double oneDouble = 24 * 60 * 60 * 1000;//一天的时间
      double days = yDouble / oneDouble;
      return (int) Math.ceil(days);
  }

}

计算两个时间的时间差（向上取整，单位：天），只计算工作日（24小时为一天），数据返回类型：int

import java.util.Date;
import java.util.Calendar;

public class DateUtils{

  public static int getDiffDayWithOutWeekends(Date yesterday, Date today) {
       
      Calendar calendar = Calendar.getInstance();
      if (yesterday == null || today== null) {
          throw new NullPointerException("by calculating the difference between two [java.util.Date]");
      }
      double yDouble = today.getTime() - yesterday.getTime();
      double oneDouble = 24 * 60 * 60 * 1000;//一天的时间
      int days = (int) (yDouble / oneDouble);
      int sum = 0;
      for (int i = 0; i < days; i++) {
          calendar.setTime(now);
          calendar.add(Calendar.DAY_OF_YEAR, -i);
          if (isWeekend(calendar)) {
              sum++;
          }
      }
      // subtract weekends
      days = days - sum;
      return days;
  }
}

判断一个日期是否是周末（星期六、星期日），数据返回类型：boolean

import java.util.Date;
import java.util.Calendar;

public class DateUtils{

    public static boolean isWeekend(Date now) {
        
        Calendar cal = Calendar.getInstance();
        cal.setTime(Objects.requireNonNull(now));
        int week = cal.get(Calendar.DAY_OF_WEEK) - 1;
        return week == 6 || week == 0;
    }
}

根据时间偏移量得到新的时间，数据返回类型：String

import java.util.Date;
import java.util.Calendar;

public class DateUtils{

    /**
     * 根据时间偏移量得到新的时间
     *
     * @param way      (1-代表天数，2-代表月数)
     * @param time     （时间偏移量，整数往后推，负数往前移动）
     * @param type     （格式化时间类型，1-"yyyy-MM-dd"，2-"yyyy-MM-dd HH:mm:ss"）
     * @param datetime （传入时间）
     * @return 得到新的时间
     */
    public static String getDate(int way, int time, int type, Date datetime) {
        
        Date date = new Date(); // 获取时间
        if (datetime != null) {
            date = datetime;
        }
        Calendar calendar = new GregorianCalendar();
        calendar.setTime(date);
        if (way == 1) {
            calendar.add(Calendar.DATE, time); // 把日期往后增加天数，整数往后推，负数往前移动
        }
        if (way == 2) {
            calendar.add(Calendar.MONTH, time); // 把日期往后增加月数，整数往后推，负数往前移动
        }
        date = calendar.getTime(); // 这个时间就是日期往后推一天的结果
        String dateString = "";
        if (type == 1) {
            SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
            dateString = formatter.format(date);
        } else if (type == 2) {
            SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            dateString = formatter.format(date);
        }
        return dateString;
    }

}

计算某个日期加上N个月之后的日期

import java.util.Date;
import java.util.Calendar;

public class DateUtils{

    /**
     * 计算某个日期加上N个月之后的日期
     *
     * @param date 当前时间
     * @param moth 月数
     * @return 结果
     */
    public static String dataAddMoth(Date date, int moth) {
        
        SimpleDateFormat fmt = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.add(Calendar.MONTH, moth);
        return fmt.format(calendar.getTime());
    }

}

传入字符串格式的日期时间，获取N小时后/N小时前的时间，数据返回类型：String

import java.util.Date;
import java.util.Calendar;
import java.text.SimpleDateFormat;

public class DateUtils{

    /**
     * 计算传入参数时间加上N个月之后的日期
     *
     * @param dateTime当前时间
     * @param i 小时数（正数向后推，负数向前推）
     * @return 结果
     */
    public static String getDateTimeString(String dateTime, int i) {

        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Date date = new Date();
        try {
            date = sdf.parse(dateTime);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.add(Calendar.HOUR_OF_DAY, i);
        return sdf.format(calendar.getTime());
    }

}

获取n天前的所有日期，数据返回类型：List

import java.util.Date;
import java.util.Calendar;
import java.text.SimpleDateFormat;

public class DateUtils{

    public final static String DATE_PATTERN = "yyyy-MM-dd";

    public static String format(Date date) {
        
        return format(date, DATE_PATTERN);
    }

    public static String format(Date date, String pattern) {
        
        if (date != null) {
            SimpleDateFormat df = new SimpleDateFormat(pattern);
            return df.format(date);
        }
        return null;
    }

    /**
     * 获取n天前的所有日期
     *
     * @param i 天数（正数向后推，负数向前推）
     * @return 结果
     */
    public static List<String> getDays(int n) {
        
        List<String> dateList = new ArrayList<String>();
        for (int j = -n; j < 0; j++) {
            Calendar cal = Calendar.getInstance();
            cal.add(Calendar.DAY_OF_MONTH, j);  // 设置为前j天
            String tempDate = format(cal.getTime());
            dateList.add(tempDate);
        }
        return dateList;
    }

}

当天开始时间，数据返回类型：String

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

public class DateUtils{

   public static final DateTimeFormatter DFY_MD_HMS = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");

   public static String todayStart() {

        LocalDateTime today_start = LocalDateTime.of(LocalDate.now(), LocalTime.MIN);
        return today_start.format(DFY_MD_HMS);
    }

}

当天结束时间，数据返回类型：String

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

public class DateUtils{

    public static String todayEnd() {

        LocalDateTime today_start = LocalDateTime.of(LocalDate.now(), LocalTime.MAX);
        return today_start.format(DFY_MD_HMS);
    }
}

获取两个日期之间的所有日期列表，数据返回类型：List

import java.time.LocalDate;

public class DateUtils{

    public static List<LocalDate> getMiddleDate(LocalDate begin, LocalDate end) {
        List<LocalDate> localDateList = new ArrayList<>();
        long length = end.toEpochDay() - begin.toEpochDay();
        for (long i = length; i >= 0; i--) {
            localDateList.add(end.minusDays(i));
        }
        return localDateList;
    }
 
}

开始日期与结束日期之间相差的天数，数据返回类型：long

import java.time.LocalDateTime;
import java.time.temporal.ChronoUnit;

public class DateUtils{

    public static long getMiddleDate(LocalDateTime startDateTime, LocalDateTime endDateTime) {

        return ChronoUnit.DAYS.between(startDateTime, endDateTime);
    }
 
}

同一天日期比较，数据返回类型：boolean

import java.time.ZonedDateTime;
import java.time.ZoneId;
import java.util.Date;

public class DateUtils{

    public static ZoneId ZONE_ID_BJ = ZoneId.of("GMT+08:00");

    public static boolean sameDate(Date d1, Date d2) {
        try {
            return ZonedDateTime.ofInstant(d1.toInstant(), ZONE_ID_BJ).toLocalDate().isEqual(
                    ZonedDateTime.ofInstant(
                            d2.toInstant(), ZONE_ID_BJ).toLocalDate());
        } catch (Exception e) {
            return false;
        }
    }
 
}

日期比较，数据返回类型：boolean

import java.time.ZonedDateTime;
import java.time.ZoneId;
import java.util.Date;

public class DateUtils{

    public static ZoneId ZONE_ID_BJ = ZoneId.of("GMT+08:00");

    public static boolean compareDate(Date d1, Date d2) {
        try {
            return ZonedDateTime.ofInstant(d1.toInstant(), ZONE_ID_BJ).toLocalDateTime().isAfter(
                    ZonedDateTime.ofInstant(
                            d2.toInstant(), ZONE_ID_BJ)
                            .toLocalDateTime());
        } catch (Exception e) {
            return false;
        }
    }
 
}

LocalDateTime转时间戳，数据返回类型：Long

import java.time.LocalDateTime;
import java.time.ZoneId;

public class DateUtils{

    public static Long getTimeStamp(LocalDateTime localDateTime) {
        return localDateTime.atZone(ZoneId.systemDefault()).toEpochSecond();
    }
 
}

时间戳转LocalDateTime，数据返回类型：LocalDateTime

import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.OffsetDateTime;

public class DateUtils{

    public static LocalDateTime fromTimeStamp(Long timeStamp) {
        return LocalDateTime.ofEpochSecond(timeStamp, 0, OffsetDateTime.now().getOffset());
    }
 
}

LocalDateTime转Date（Jdk8后，不推荐使用Date），数据返回类型：Date

import java.time.LocalDateTime;
import java.time.ZoneId;

public class DateUtils{

    /**
     * LocalDateTime 转 Date
     * Jdk8 后 不推荐使用 {@link Date} Date
     *
     * @param localDateTime /
     * @return /
     */
    public static Date toDate(LocalDateTime localDateTime) {
        return Date.from(localDateTime.atZone(ZoneId.systemDefault()).toInstant());
    }

}

LocalDate转Date，数据返回类型：Date

import java.time.LocalDateTime;
import java.time.ZoneId;

public class DateUtils{

    /**
     * LocalDate 转 Date
     * Jdk8 后 不推荐使用 {@link Date} Date
     *
     * @param localDate /
     * @return /
     */
    public static Date toDate(LocalDate localDate) {
        return toDate(localDate.atTime(LocalTime.now(ZoneId.systemDefault())));
    }

}

Date转LocalDateTime，数据返回类型：LocalDateTime

import java.time.LocalDateTime;
import java.time.ZoneId;

public class DateUtils{

    /**
     * Date转 LocalDateTime
     * Jdk8 后 不推荐使用 {@link Date} Date
     *
     * @param date /
     * @return /
     */
    public static LocalDateTime toLocalDateTime(Date date) {
        return LocalDateTime.ofInstant(date.toInstant(), ZoneId.systemDefault());
    }

}

LocalDateTime日期格式化，数据返回类型：String

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

public class DateUtils{

    /**
     * 日期 格式化
     *
     * @param localDateTime /
     * @param patten        /
     * @return /
     */
    public static String localDateTimeFormat(LocalDateTime localDateTime, String patten) {
        DateTimeFormatter df = DateTimeFormatter.ofPattern(patten);
        return df.format(localDateTime);
    }

}

字符串转LocalDateTime，字符串格式 yyyy-MM-dd / yyyy-MM-dd HH:mm:ss，数据返回类型：LocalDateTime

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

public class DateUtils{

    /**
     * 字符串转 LocalDateTime ，字符串格式 yyyy-MM-dd / yyyy-MM-dd HH:mm:ss
     *
     * @param localDateTime /
     * @return /
     */
    public static LocalDateTime parseLocalDateTimeFormat(String localDateTime, String pattern) {
        
        DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern(pattern);
        return LocalDateTime.from(dateTimeFormatter.parse(localDateTime));
    }

}

获取当天的每个小时，数据返回类型：List

import java.util.Date;
import java.util.Calendar;
import java.text.SimpleDateFormat;

public class DateUtils{

    public static List<String> findHoursStr() {
        
        Date day = new Date();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd 00:00:00");
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String s = sdf.format(day);
        Date date = null;
        try {
            date = sdf.parse(s);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        ArrayList<String> hoursStrList = new ArrayList<String>();
        hoursStrList.add(format.format(date));
        for (int i = 1; i < 24; i++) {
            Calendar cal = Calendar.getInstance();
            cal.setTime(Objects.requireNonNull(date));
            cal.add(Calendar.HOUR, 1);
            date = cal.getTime();
            String hourStr = format.format(date);
            hoursStrList.add(hourStr);
        }
        return hoursStrList;
    }
}

获取服务器启动时间，数据返回类型：Date

import java.util.Date;
import java.lang.management.ManagementFactory;

public class DateUtils{

    public static Date getServerStartDate() {
        long time = ManagementFactory.getRuntimeMXBean().getStartTime();
        return new Date(time);
    }

}

计算两个时间差，数据返回类型：String

import java.util.Date;

public class DateUtils{

    public static String getDatePoor(Date endDate, Date nowDate) {

        long nd = 1000 * 24 * 60 * 60;
        long nh = 1000 * 60 * 60;
        long nm = 1000 * 60;
        // long ns = 1000;
        // 获得两个时间的毫秒时间差异
        long diff = endDate.getTime() - nowDate.getTime();
        // 计算差多少天
        long day = diff / nd;
        // 计算差多少小时
        long hour = diff % nd / nh;
        // 计算差多少分钟
        long min = diff % nd % nh / nm;
        // 计算差多少秒//输出结果
        // long sec = diff % nd % nh % nm / ns;
        return day + "天" + hour + "小时" + min + "分钟";
    }
}

计算两个时间分钟差，数据返回类型：String

import java.time.LocalDateTime;
import java.time.ZoneId;

public class DateUtils{

    public static String getMinutePoor(Date endDate, Date nowDate) {
        
        long nd = 1000 * 24 * 60 * 60;
        long nh = 1000 * 60 * 60;
        long nm = 1000 * 60;
        // 获得两个时间的毫秒时间差异
        long diff = endDate.getTime() - nowDate.getTime();
        // 计算差多少分钟
        long min = diff / nm;
        if (min < 1) {
            return "1分钟";
        }
        return min + "分钟";
    }

}

判断两个日期是否是同一周，数据返回类型：boolean

import java.util.Date;
import java.util.Calendar;

public class DateUtils{

    public static boolean isSameWeek(Date startTime, Date endTime) {
        
        Calendar calendar = Calendar.getInstance();
        calendar.setFirstDayOfWeek(Calendar.MONDAY); // 设置一周的第一天是星期几
        calendar.setTime(startTime);
        int startWeek = calendar.get(Calendar.WEEK_OF_YEAR);
        calendar.setTime(endTime);
        int endWeek = calendar.get(Calendar.WEEK_OF_YEAR);
        if (endWeek == startWeek) {
            return true;
        }
        return false;
    }
}

判断两个日期是否是同一天，数据返回类型：boolean

import java.time.LocalDateTime;
import java.time.ZoneId;

public class DateUtils{

    public static boolean isSameTime(Date startTime, Date endTime, String pattern) {
        SimpleDateFormat sdf = new SimpleDateFormat(pattern);
        String start = sdf.format(startTime); // 参数时间
        String end = sdf.format(endTime); // 当前时间
        if (start.equals(end)) {
            return true;
        }
        return false;
    }
}

生死看淡、不服就干

我们都知道我们正在为自由而奋斗，根据我们自己的观念来决定我们的一生。 We know that we are fighting for freedom to shape our life according to our own ideas.
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原文地址：https://www.cnblogs.com/focus-yun/p/14683847.html