Java获取时间/格式化日期代码总结

java.util.Date
java.sql.Date  
java.sql.Time  
java.sql.Timestamp
java.text.SimpleDateFormat
java.util.Calendar

Date:getTime() 、setTime()
DateFormat:getInstance()、getDateInstance()、getDateTimeInstance()、getTimeInstance()
SimpleDateFormate:Formate(Date)、 parse(String s)
Calendar:getInstance()、set() 、get()、getActualMaximum()、add()、gettime()、setTime(Date)

import java.text.DateFormat;
import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;

public class FormatDate {
  private static int weeks = 0;// 用来全局控制 上一周，本周，下一周的周数变化
  private static int MaxDate;// 一月最大天数
  private static int MaxYear;// 一年最大天数

  /**
   * 主方法，测试
   * 
   * @param args
   */
  public static void main(String[] args) {
    System.out.println("得到6个月后的日期:" + getAfterMonth(6));
    System.out.println("获取当天日期:" + getNowTime("yyyy-MM-dd"));
    System.out.println("获取本周一日期:" + getMondayOFWeek());
    System.out.println("获取本周日的日期~:" + getCurrentWeekday());
    System.out.println("获取上周一日期:" + getPreviousWeekday());
    System.out.println("获取上周日日期:" + getPreviousWeekSunday());
    System.out.println("获取下周一日期:" + getNextMonday());
    System.out.println("获取下周日日期:" + getNextSunday());
    System.out.println("获得相应周的周六:" + getNowTime("yyyy-MM-dd"));
    System.out.println("获取本月第一天日期:" + getFirstDayOfMonth());
    System.out.println("获取本月最后一天日期:" + getDefaultDay());
    System.out.println("获取上月第一天日期:" + getPreviousMonthFirst());
    System.out.println("获取上月最后一天的日期:" + getPreviousMonthEnd());
    System.out.println("获取下月第一天日期:" + getNextMonthFirst());
    System.out.println("获取下月最后一天日期:" + getNextMonthEnd());
    System.out.println("获取本年的第一天日期:" + getCurrentYearFirst());
    System.out.println("获取本年最后一天日期:" + getCurrentYearEnd());
    System.out.println("获取去年的第一天日期:" + getPreviousYearFirst());
    System.out.println("获取去年的最后一天日期:" + getPreviousYearEnd());
    System.out.println("获取明年第一天日期:" + getNextYearFirst());
    System.out.println("获取明年最后一天日期:" + getNextYearEnd());
    System.out.println("获取本季度第一天到最后一天:" + getThisSeasonTime(11));
    System.out.println("获取两个日期之间间隔天数2018-12-1~2018-12.29的间隔天数是:" + getTwoDay("2018-12-1", "2018-12-29"));
  }

  /**
   * 得到指定月后（前）的日期 参数传负数即可
   */
  public static String getAfterMonth(int month) {
    Calendar c = Calendar.getInstance();// 获得一个日历的实例
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Date date = null;
    try {
      date = sdf.parse(getNowTime("yyyy-MM-dd"));// 初始日期
    } catch (Exception e) {
    }
    c.setTime(date);// 设置日历时间
    c.add(Calendar.MONTH, month);// 在日历的月份上增加6个月
    String strDate = sdf.format(c.getTime());// 的到你想要得6个月后的日期
    return strDate;
  }

  /**
   * 得到二个日期间的间隔天数
   */
  public static String getTwoDay(String sj1, String sj2) {
    SimpleDateFormat myFormatter = new SimpleDateFormat("yyyy-MM-dd");
    long day = 0;
    try {
      java.util.Date date = myFormatter.parse(sj1);
      java.util.Date mydate = myFormatter.parse(sj2);
      day = (date.getTime() - mydate.getTime()) / (24 * 60 * 60 * 1000);
    } catch (Exception e) {
      return "";
    }
    return day + "";
  }

  /**
   * 根据一个日期，返回是星期几的字符串
   */
  public static String getWeek(String sdate) {
    // 再转换为时间
    Date date = strToDate(sdate);
    Calendar c = Calendar.getInstance();
    c.setTime(date);
    // int hour=c.get(Calendar.DAY_OF_WEEK);
    // hour 中存的就是星期几了，其范围 1~7
    // 1=星期日 7=星期六，其他类推
    return new SimpleDateFormat("EEEE").format(c.getTime());
  }

  /**
   * 将短时间格式字符串转换为时间 yyyy-MM-dd
   */
  public static Date strToDate(String strDate) {
    SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
    ParsePosition pos = new ParsePosition(0);
    Date strtodate = formatter.parse(strDate, pos);
    return strtodate;
  }

  /**
   * 两个时间之间的天数
   *
   * @param date1
   * @param date2
   * @return
   */
  public static long getDays(String date1, String date2) {
    if (date1 == null || date1.equals(""))
      return 0;
    if (date2 == null || date2.equals(""))
      return 0;
    // 转换为标准时间
    SimpleDateFormat myFormatter = new SimpleDateFormat("yyyy-MM-dd");
    java.util.Date date = null;
    java.util.Date mydate = null;
    try {
      date = myFormatter.parse(date1);
      mydate = myFormatter.parse(date2);
    } catch (Exception e) {
    }
    long day = (date.getTime() - mydate.getTime()) / (24 * 60 * 60 * 1000);
    return day;
  }

  // 计算当月最后一天,返回字符串
  public static String getDefaultDay() {
    String str = "";
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Calendar lastDate = Calendar.getInstance();
    lastDate.set(Calendar.DATE, 1);// 设为当前月的1 号
    lastDate.add(Calendar.MONTH, 1);// 加一个月，变为下月的1 号
    lastDate.add(Calendar.DATE, -1);// 减去一天，变为当月最后一天
    str = sdf.format(lastDate.getTime());
    return str;
  }

  // 上月第一天
  public static String getPreviousMonthFirst() {
    String str = "";
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Calendar lastDate = Calendar.getInstance();
    lastDate.set(Calendar.DATE, 1);// 设为当前月的1 号
    lastDate.add(Calendar.MONTH, -1);// 减一个月，变为下月的1 号
    // lastDate.add(Calendar.DATE,-1);//减去一天，变为当月最后一天
    str = sdf.format(lastDate.getTime());
    return str;
  }

  // 获取当月第一天
  public static String getFirstDayOfMonth() {
    String str = "";
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Calendar lastDate = Calendar.getInstance();
    lastDate.set(Calendar.DATE, 1);// 设为当前月的1 号
    str = sdf.format(lastDate.getTime());
    return str;
  }

  // 获得本周星期日的日期
  public static String getCurrentWeekday() {
    weeks = 0;
    int mondayPlus = getMondayPlus();
    GregorianCalendar currentDate = new GregorianCalendar();
    currentDate.add(GregorianCalendar.DATE, mondayPlus + 6);
    Date monday = currentDate.getTime();
    DateFormat df = DateFormat.getDateInstance();
    String preMonday = df.format(monday);
    return preMonday;
  }

  /**
   * 获取当天时间
   * 
   * @param dateformat
   * @return
   */
  public static String getNowTime(String dateformat) {
    Date now = new Date();
    SimpleDateFormat dateFormat = new SimpleDateFormat(dateformat);// 可以方便地修改日期格式
    String hehe = dateFormat.format(now);
    return hehe;
  }

  /**
   * 获得当前日期与本周日相差的天数
   * 
   * @return
   */
  private static int getMondayPlus() {
    Calendar cd = Calendar.getInstance();
    // 获得今天是一周的第几天，星期日是第一天，星期二是第二天......
    int dayOfWeek = cd.get(Calendar.DAY_OF_WEEK) - 1; // 因为按中国礼拜一作为第一天所以这里减1
    if (dayOfWeek == 1) {
      return 0;
    } else {
      return 1 - dayOfWeek;
    }
  }

  /**
   * 获得本周一的日期
   * 
   * @return
   */
  public static String getMondayOFWeek() {
    weeks = 0;
    int mondayPlus = getMondayPlus();
    GregorianCalendar currentDate = new GregorianCalendar();
    currentDate.add(GregorianCalendar.DATE, mondayPlus);
    Date monday = currentDate.getTime();
    DateFormat df = DateFormat.getDateInstance();
    String preMonday = df.format(monday);
    return preMonday;
  }

  /**
   * 获得相应周的周六的日期
   * 
   * @return
   */
  public String getSaturday() {
    int mondayPlus = getMondayPlus();
    GregorianCalendar currentDate = new GregorianCalendar();
    currentDate.add(GregorianCalendar.DATE, mondayPlus + 7 * weeks + 6);
    Date monday = currentDate.getTime();
    DateFormat df = DateFormat.getDateInstance();
    String preMonday = df.format(monday);
    return preMonday;
  }

  /**
   * 获得上周星期日的日期
   * 
   * @return
   */
  public static String getPreviousWeekSunday() {
    weeks = 0;
    weeks--;
    int mondayPlus = getMondayPlus();
    GregorianCalendar currentDate = new GregorianCalendar();
    currentDate.add(GregorianCalendar.DATE, mondayPlus + weeks);
    Date monday = currentDate.getTime();
    DateFormat df = DateFormat.getDateInstance();
    String preMonday = df.format(monday);
    return preMonday;
  }

  /**
   * 获得上周星期一的日期
   * 
   * @return
   */
  public static String getPreviousWeekday() {
    weeks--;
    int mondayPlus = getMondayPlus();
    GregorianCalendar currentDate = new GregorianCalendar();
    currentDate.add(GregorianCalendar.DATE, mondayPlus + 7 * weeks);
    Date monday = currentDate.getTime();
    DateFormat df = DateFormat.getDateInstance();
    String preMonday = df.format(monday);
    return preMonday;
  }

  /**
   * 获得下周星期一的日期
   * 
   * @return
   */
  public static String getNextMonday() {
    weeks++;
    int mondayPlus = getMondayPlus();
    GregorianCalendar currentDate = new GregorianCalendar();
    currentDate.add(GregorianCalendar.DATE, mondayPlus + 7);
    Date monday = currentDate.getTime();
    DateFormat df = DateFormat.getDateInstance();
    String preMonday = df.format(monday);
    return preMonday;
  }

  /**
   * 获得下周星期日的日期
   * 
   * @return
   */
  public static String getNextSunday() {
    int mondayPlus = getMondayPlus();
    GregorianCalendar currentDate = new GregorianCalendar();
    currentDate.add(GregorianCalendar.DATE, mondayPlus + 7 + 6);
    Date monday = currentDate.getTime();
    DateFormat df = DateFormat.getDateInstance();
    String preMonday = df.format(monday);
    return preMonday;
  }

  /**
   * 获取今天是本月第几天
   */
  public static int getMonthPlus() {
    Calendar cd = Calendar.getInstance();
    int monthOfNumber = cd.get(Calendar.DAY_OF_MONTH);
    cd.set(Calendar.DATE, 1);// 把日期设置为当月第一天
    cd.roll(Calendar.DATE, -1);// 日期回滚一天，也就是最后一天
    MaxDate = cd.get(Calendar.DATE);
    if (monthOfNumber == 1) {
      return -MaxDate;
    } else {
      return 1 - monthOfNumber;
    }
  }

  /**
   * 获得上月最后一天的日期
   * 
   * @return
   */
  public static String getPreviousMonthEnd() {
    String str = "";
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Calendar lastDate = Calendar.getInstance();
    lastDate.add(Calendar.MONTH, -1);// 减一个月
    lastDate.set(Calendar.DATE, 1);// 把日期设置为当月第一天
    lastDate.roll(Calendar.DATE, -1);// 日期回滚一天，也就是本月最后一天
    str = sdf.format(lastDate.getTime());
    return str;
  }

  /**
   * 获得下个月第一天的日期
   * 
   * @return
   */
  public static String getNextMonthFirst() {
    String str = "";
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Calendar lastDate = Calendar.getInstance();
    lastDate.add(Calendar.MONTH, 1);// 减一个月
    lastDate.set(Calendar.DATE, 1);// 把日期设置为当月第一天
    str = sdf.format(lastDate.getTime());
    return str;
  }

  /**
   * 获得下个月最后一天的日期
   * 
   * @return
   */
  public static String getNextMonthEnd() {
    String str = "";
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Calendar lastDate = Calendar.getInstance();
    lastDate.add(Calendar.MONTH, 1);// 加一个月
    lastDate.set(Calendar.DATE, 1);// 把日期设置为当月第一天
    lastDate.roll(Calendar.DATE, -1);// 日期回滚一天，也就是本月最后一天
    str = sdf.format(lastDate.getTime());
    return str;
  }

  /**
   * 获得明年最后一天的日期
   * 
   * @return
   */
  public static String getNextYearEnd() {
    String str = "";
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Calendar lastDate = Calendar.getInstance();
    lastDate.add(Calendar.YEAR, 1);// 加一个年
    lastDate.set(Calendar.DAY_OF_YEAR, 1);
    lastDate.roll(Calendar.DAY_OF_YEAR, -1);
    str = sdf.format(lastDate.getTime());
    return str;
  }

  /**
   * 获得明年第一天的日期
   * 
   * @return
   */
  public static String getNextYearFirst() {
    String str = "";
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Calendar lastDate = Calendar.getInstance();
    lastDate.add(Calendar.YEAR, 1);// 加一个年
    lastDate.set(Calendar.DAY_OF_YEAR, 1);
    str = sdf.format(lastDate.getTime());
    return str;
  }

  /**
   * 获得本年有多少天
   * 
   * @return
   */
  public static int getMaxYear() {
    Calendar cd = Calendar.getInstance();
    cd.set(Calendar.DAY_OF_YEAR, 1);// 把日期设为当年第一天
    cd.roll(Calendar.DAY_OF_YEAR, -1);// 把日期回滚一天。
    int MaxYear = cd.get(Calendar.DAY_OF_YEAR);
    return MaxYear;
  }

  /**
   * 当天是一年中的第几天
   * 
   * @return
   */
  public static int getYearPlus() {
    Calendar cd = Calendar.getInstance();
    int yearOfNumber = cd.get(Calendar.DAY_OF_YEAR);// 获得当天是一年中的第几天
    cd.set(Calendar.DAY_OF_YEAR, 1);// 把日期设为当年第一天
    cd.roll(Calendar.DAY_OF_YEAR, -1);// 把日期回滚一天。
    int MaxYear = cd.get(Calendar.DAY_OF_YEAR);
    if (yearOfNumber == 1) {
      return -MaxYear;
    } else {
      return 1 - yearOfNumber;
    }
  }

  /**
   * 获得本年第一天的日期
   * 
   * @return
   */
  public static String getCurrentYearFirst() {
    int yearPlus = getYearPlus();
    GregorianCalendar currentDate = new GregorianCalendar();
    currentDate.add(GregorianCalendar.DATE, yearPlus);
    Date yearDay = currentDate.getTime();
    DateFormat df = DateFormat.getDateInstance();
    String preYearDay = df.format(yearDay);
    return preYearDay;
  }

  /**
   * 获得本年最后一天的日期 *
   * 
   * @return
   */
  public static String getCurrentYearEnd() {
    Date date = new Date();
    SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy");// 可以方便地修改日期格式
    String years = dateFormat.format(date);
    return years + "-12-31";
  }

  /**
   * 获得上年第一天的日期 *
   * 
   * @return
   */
  public static String getPreviousYearFirst() {
    Date date = new Date();
    SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy");// 可以方便地修改日期格式
    String years = dateFormat.format(date);
    int years_value = Integer.parseInt(years);
    years_value--;
    return years_value + "-1-1";
  }

  /**
   * 获得上年最后一天的日期
   * 
   * @return
   */
  public static String getPreviousYearEnd() {
    weeks--;
    int yearPlus = getYearPlus();
    GregorianCalendar currentDate = new GregorianCalendar();
    currentDate.add(GregorianCalendar.DATE, yearPlus + MaxYear * weeks + (MaxYear - 1));
    Date yearDay = currentDate.getTime();
    DateFormat df = DateFormat.getDateInstance();
    String preYearDay = df.format(yearDay);
    getThisSeasonTime(11);
    return preYearDay;
  }

  /**
   * 获得本季度
   * 
   * @param month
   * @return
   */
  public static String getThisSeasonTime(int month) {
    int array[][] = { { 1, 2, 3 }, { 4, 5, 6 }, { 7, 8, 9 }, { 10, 11, 12 } };
    int season = 1;
    if (month >= 1 && month <= 3) {
      season = 1;
    }
    if (month >= 4 && month <= 6) {
      season = 2;
    }
    if (month >= 7 && month <= 9) {
      season = 3;
    }
    if (month >= 10 && month <= 12) {
      season = 4;
    }
    int start_month = array[season - 1][0];
    int end_month = array[season - 1][2];
    Date date = new Date();
    SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy");// 可以方便地修改日期格式
    String years = dateFormat.format(date);
    int years_value = Integer.parseInt(years);
    int start_days = 1;
    // years+"-"+String.valueOf(start_month)+"-";
    // getLastDayOfMonth(years_value,start_month);
    int end_days = getLastDayOfMonth(years_value, end_month);
    String seasonDate = years_value + "-" + start_month + "-" + start_days + ";" + years_value + "-" + end_month
        + "-" + end_days;
    return seasonDate;
  }

  /**
   * 获取某年某月的最后一天
   * 
   * @param year
   *            年
   * @param month
   *            月
   * @return 最后一天
   */
  private static int getLastDayOfMonth(int year, int month) {
    if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12) {
      return 31;
    }
    if (month == 4 || month == 6 || month == 9 || month == 11) {
      return 30;
    }
    if (month == 2) {
      if (isLeapYear(year)) {
        return 29;
      } else {
        return 28;
      }
    }
    return 0;
  }

  /**
   * 是否闰年
   * 
   * @param year
   *            年
   * @return
   */
  public static boolean isLeapYear(int year) {
    return (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0);
  }
}