Java 之 Date 和 Calendar 实例

package com.homer.learn; 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 TimeTest { public static void main(String[] args) { TimeTest tt = new TimeTest(); System.out.println("\n当前日期： "); System.out.println(tt.getNowTime()); // 获取当前时间 System.out.println(tt.getNowTime2()); // 获取当前时间 System.out.println(tt.getNowTime3()); // 获取当前时间 System.out.println("\n计算周： "); System.out.println(tt.getDaysOfNow2SundayInWeek()); // 获取当前日期与本周日的相差天数 System.out.println(tt.getDateOfMondayInWeek()); // 获取本周一的日期 System.out.println(tt.getDateOfSaturdayInWeek()); // 获取本周六的日期 System.out.println(tt.getDateOfSaturdayInNextWeek()); // 获取下周一的日期 System.out.println(tt.getDateOfSaturdayInLastWeek()); // 获取上周一的日期 System.out.println("\n计算月： "); System.out.println(tt.getFirstDayOfMonth()); // 获取当月的第一天 System.out.println(tt.getLastDayOfMonth()); // 获取当月最后一天 System.out.println(tt.getFirstDayOfPreviousMonth()); // 获取上月第一天 System.out.println(tt.getLastDayOfPreviousMonth()); // 获取上月最后一天 System.out.println(tt.getFirstDayOfNextMonth()); // 获取下月第一天 System.out.println(tt.getLastDayOfNextMonth()); // 获取下月最后一天 System.out.println("\n计算年： "); System.out.println(tt.getFirstDayOfYear()); // 获取本年的第一天 System.out.println(tt.getLastDayOfYear()); // 获取本年最后一天 System.out.println(tt.getFirstDayOfPreviousYear()); // 获取上年的第一天 System.out.println(tt.getLastDayOfPreviousYear()); // 获取上年最后一天 System.out.println(tt.getFirstDayOfNextYear()); // 获取下年的第一天 System.out.println(tt.getLastDayOfNextYear()); // 获取下年最后一天 System.out.println(tt.getDaysOfYear()); // 获取本年的天数 System.out.println("\n计算季度： "); System.out.println(tt.getSeasonOfMonth()); // 获取当前月的季度 System.out.println(tt.getLastDayOfNow()); // 获取当前天所在月份的天数 System.out.println(tt.isLeapYear(2012)); // 判断是否是润年 System.out.println("\n日期格式转换与计算： "); System.out.println(tt.getDateFromStr("2012-06-20")); // 将字符串时间格式 yyyy-MM-dd，转换成Date类型 System.out.println(tt.getWeek("2012-06-20")); // 根据一个日期，返回是星期几的字符串 System.out.print("2012-06-02 -> 2012-06-12间隔天数:"); // 计算两个日期间的间隔天数 System.out.println(tt.getDaysFromTwoDate("2012-06-02", "2012-06-12")); } // 获取当前时间 public String getNowTime() { SimpleDateFormat sDateFormat = new SimpleDateFormat("yyyy-MM-dd"); Date now = new Date(); return sDateFormat.format(now); } public String getNowTime2() { SimpleDateFormat sDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); Date now = new Date(System.currentTimeMillis()); return sDateFormat.format(now); } public String getNowTime3() { StringBuilder strBuildNow = new StringBuilder(); Calendar calendar = Calendar.getInstance(); int year = calendar.get(Calendar.YEAR); int month = calendar.get(Calendar.MONTH) + 1; int day = calendar.get(Calendar.DAY_OF_MONTH); int hour = calendar.get(Calendar.HOUR_OF_DAY); int minute = calendar.get(Calendar.MINUTE); int second = calendar.get(Calendar.SECOND); int millissecond = calendar.get(Calendar.MILLISECOND); strBuildNow.append(year + "-"); strBuildNow.append(month + "-"); strBuildNow.append(day + " "); strBuildNow.append(hour + ":"); strBuildNow.append(minute + ":"); strBuildNow.append(second + "."); strBuildNow.append(millissecond); return strBuildNow.toString(); } // 获取当前日期与本周日的相差天数 public int getDaysOfNow2SundayInWeek() { Calendar calendar = Calendar.getInstance(); int dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK) - 1; // 减一天，周一为1，符合中国人习惯。Sunday - 1; Monday - 2; Saturday - 7 if(dayOfWeek == 0) { // 周日 return 0; } else { return 0 - dayOfWeek; } } // 获取本周一的日期 public String getDateOfMondayInWeek(){ int day = this.getDaysOfNow2SundayInWeek() + 1; // 加1，即周一离本周日的间隔天数 GregorianCalendar gCalendar = new GregorianCalendar(); gCalendar.add(GregorianCalendar.DATE, day); // 计算与本周一相差的时间间隔 Date curDay = gCalendar.getTime(); DateFormat dateFormat = DateFormat.getInstance(); String dateOfMonday = dateFormat.format(curDay); return dateOfMonday; } // 获取本周六的日期 public String getDateOfSaturdayInWeek(){ int day = this.getDaysOfNow2SundayInWeek() + 6; // 加6，即周六离本周日的间隔天数 GregorianCalendar gCalendar = new GregorianCalendar(); gCalendar.add(GregorianCalendar.DATE, day); // 计算与本周六相差的时间间隔 Date curDay = gCalendar.getTime(); DateFormat dateFormat = DateFormat.getInstance(); String dateOfMonday = dateFormat.format(curDay); return dateOfMonday; } // 获取上周一的日期 public String getDateOfSaturdayInLastWeek(){ int day = this.getDaysOfNow2SundayInWeek() - 1; // 减1，即上周一离本周日的间隔天数 GregorianCalendar gCalendar = new GregorianCalendar(); gCalendar.add(GregorianCalendar.DATE, day); // 计算与上周一相差的时间间隔 Date curDay = gCalendar.getTime(); DateFormat dateFormat = DateFormat.getInstance(); String dateOfMonday = dateFormat.format(curDay); return dateOfMonday; } // 获取下周一的日期 public String getDateOfSaturdayInNextWeek(){ int day = this.getDaysOfNow2SundayInWeek() + 8; // 加8，即下周一离本周日的间隔天数 GregorianCalendar gCalendar = new GregorianCalendar(); gCalendar.add(GregorianCalendar.DATE, day); // 计算与下周一相差的时间间隔 Date curDay = gCalendar.getTime(); DateFormat dateFormat = DateFormat.getInstance(); String dateOfMonday = dateFormat.format(curDay); return dateOfMonday; } // 获取当月第一天 public String getFirstDayOfMonth() { String strFirstDay = ""; SimpleDateFormat sDateFormat = new SimpleDateFormat("yyyy-MM-dd"); Calendar calendar = Calendar.getInstance(); calendar.set(Calendar.DATE, 1); // 设置当前月的1号 strFirstDay = sDateFormat.format(calendar.getTime()); return strFirstDay; } // 获取当月最后一天 public String getLastDayOfMonth() { String strLastDay = ""; SimpleDateFormat sDateFormat = new SimpleDateFormat("yyyy-MM-dd"); Calendar calendar = Calendar.getInstance(); calendar.set(Calendar.DATE, 1); // 设置当前月的1号 calendar.add(Calendar.MONDAY, 1); // 加一个月，变为下月的1号 calendar.add(Calendar.DATE, -1); // 减去一天，变为当前月的最后一天 strLastDay = sDateFormat.format(calendar.getTime()); return strLastDay; } // 获取上月第一天 public String getFirstDayOfPreviousMonth() { String strFirstDay = ""; SimpleDateFormat sDateFormat = new SimpleDateFormat("yyyy-MM-dd"); Calendar calendar = Calendar.getInstance(); calendar.set(Calendar.DATE, 1); // 设置当前月的1号 calendar.add(Calendar.MONDAY, -1); // 减一个月，变为上月的1号 strFirstDay = sDateFormat.format(calendar.getTime()); return strFirstDay; } // 获取上月最后一天 public String getLastDayOfPreviousMonth() { String strLastDay = ""; SimpleDateFormat sDateFormat = new SimpleDateFormat("yyyy-MM-dd"); Calendar calendar = Calendar.getInstance(); calendar.set(Calendar.DATE, 1); // 设置当前月的1号 calendar.add(Calendar.DATE, -1); // 减一天，变为上月的1号 strLastDay = sDateFormat.format(calendar.getTime()); return strLastDay; } public String getLastDayOfPreviousMonth2() { String strLastDay = ""; SimpleDateFormat sDateFormat = new SimpleDateFormat("yyyy-MM-dd"); Calendar calendar = Calendar.getInstance(); calendar.add(Calendar.MONDAY, -1); // 减一个月 calendar.set(Calendar.DATE, 1); // 设置当前月的1号 calendar.roll(Calendar.DATE, -1); // 把日期回滚一天，也就是本月最后一天 strLastDay = sDateFormat.format(calendar.getTime()); return strLastDay; } // 获取下月第一天 public String getFirstDayOfNextMonth() { String strFirstDay = ""; SimpleDateFormat sDateFormat = new SimpleDateFormat("yyyy-MM-dd"); Calendar calendar = Calendar.getInstance(); calendar.add(Calendar.MONTH, 1); // 加一个月 calendar.set(Calendar.DATE, 1); // 设置当前月第一天 strFirstDay = sDateFormat.format(calendar.getTime()); return strFirstDay; } // 获取下月最后一天 public String getLastDayOfNextMonth() { String strLastDay = ""; SimpleDateFormat sDateFormat = new SimpleDateFormat("yyyy-MM-dd"); Calendar calendar = Calendar.getInstance(); calendar.set(Calendar.DATE, 1); // 设置当前月的1号 calendar.add(Calendar.MONDAY, 2); // 加两个月，变为下下月的1号 calendar.add(Calendar.DATE, -1); // 减一天，变为下月的最后一天 strLastDay = sDateFormat.format(calendar.getTime()); return strLastDay; } public String getLastDayOfNextMonth2(){ String strLastDay = ""; SimpleDateFormat sDateFormat = new SimpleDateFormat("yyyy-MM-dd"); Calendar calendar = Calendar.getInstance(); calendar.add(Calendar.MONTH, 1); // 加1个月 calendar.set(Calendar.DATE, 1); // 把日期设置为当月第1天 calendar.roll(Calendar.DATE, -1); // 日期回滚1天，也就是本月最后1天 strLastDay = sDateFormat.format(calendar.getTime()); return strLastDay; } // 获取本年的第一天 public String getFirstDayOfYear(){ String strFirstDay = ""; SimpleDateFormat sDateFormat = new SimpleDateFormat("yyyy-MM-dd"); Calendar calendar = Calendar.getInstance(); calendar.set(Calendar.DAY_OF_YEAR, 1); // 设置当年第一天 strFirstDay = sDateFormat.format(calendar.getTime()); return strFirstDay; } // 获取本年的最后一天 public String getLastDayOfYear(){ String strLastDay = ""; Calendar calendar = Calendar.getInstance(); strLastDay = calendar.get(Calendar.YEAR) + "-12-31"; return strLastDay; } // 获取上年的第一天 public String getFirstDayOfPreviousYear(){ String strFirstDay = ""; Calendar calendar = Calendar.getInstance(); strFirstDay = (calendar.get(Calendar.YEAR) - 1) + "-01-01"; return strFirstDay; } // 获取上年的最后一天 public String getLastDayOfPreviousYear(){ String strLastDay = ""; Calendar calendar = Calendar.getInstance(); strLastDay = (calendar.get(Calendar.YEAR) - 1) + "-12-31"; return strLastDay; } // 获取下年的第一天 public String getFirstDayOfNextYear(){ String strFirstDay = ""; SimpleDateFormat sDateFormat = new SimpleDateFormat("yyyy-MM-dd"); Calendar calendar = Calendar.getInstance(); calendar.add(Calendar.YEAR, 1); // 加一年 calendar.set(Calendar.DAY_OF_YEAR, 1); // 设置当年第一天 strFirstDay = sDateFormat.format(calendar.getTime()); return strFirstDay; } // 获取下年的最后一天 public String getLastDayOfNextYear(){ String strLastDay = ""; SimpleDateFormat sDateFormat = new SimpleDateFormat("yyyy-MM-dd"); Calendar calendar = Calendar.getInstance(); calendar.add(Calendar.YEAR, 1); // 加一年 calendar.set(Calendar.DAY_OF_YEAR, 1); // 设置当年第一天 calendar.roll(Calendar.DAY_OF_YEAR, -1); // 回滚到当年最后一天 strLastDay = sDateFormat.format(calendar.getTime()); return strLastDay; } // 获取本年的天数 public String getDaysOfYear(){ int year = 0; int days = 0; Calendar calendar = Calendar.getInstance(); calendar.set(Calendar.DAY_OF_YEAR, 1); // 设置日期为当年第一天 calendar.roll(Calendar.DAY_OF_YEAR, -1); // 把日期回滚一天 year = calendar.get(Calendar.YEAR); days = calendar.get(Calendar.DAY_OF_YEAR); return (days + " in " + year); } // 获取当前月的季度 public String getSeasonOfMonth(){ String strSeason = ""; int year, month, day; int season = 1; int array[][] = new int[][]{ {1,2,3}, {4,5,6}, {7,8,9}, {10,11,12} }; Calendar calendar = Calendar.getInstance(); year = calendar.get(Calendar.YEAR); month = calendar.get(Calendar.MONDAY) + 1; day = calendar.get(Calendar.DAY_OF_MONTH); switch (month) { case 1: case 2: case 3: season = 1; break; case 4: case 5: case 6: season = 2; break; case 7: case 8: case 9: season = 3; break; case 10: case 11: case 12: season = 4; break; default: season = 1; break; } int start_month = array[season-1][0]; int end_month = array[season-1][2]; strSeason = year + "-" + month + "-" +day; strSeason += " in [ " + year + "-" + start_month + " : " + year + "-" + end_month + " ]"; return strSeason; } // 获取当前天所在月份的天数 public String getLastDayOfNow(){ String strLastDay = ""; int year, month, day; int days = 0; Calendar calendar = Calendar.getInstance(); year = calendar.get(Calendar.YEAR); month = calendar.get(Calendar.MONTH) + 1; day = calendar.get(Calendar.DAY_OF_MONTH); switch (month) { case 1: case 3: case 5: case 7: case 8: case 10: case 12: days = 31; break; case 4: case 6: case 9: case 11: days = 30; break; case 2: if (isLeapYear(year)) { days = 29; } else { days = 28; } break; default: days = 0; break; } strLastDay = days + " in [ " + year + "-" + month + "-" + day + " ]"; return strLastDay; } // 判断是否是润年 public boolean isLeapYear(int year){ return (year%4 == 0 && year%100 != 0) || (year%400 == 0); } // 将字符串时间格式 yyyy-MM-dd，转换成Date类型 public Date getDateFromStr(String txtDate) { SimpleDateFormat sDateFormat = new SimpleDateFormat("yyyy-MM-dd"); ParsePosition pos = new ParsePosition(0); Date date = sDateFormat.parse(txtDate, pos); return date; } // 根据一个日期，返回是星期几的字符串 public String getWeek(String txtDate) { Date date = getDateFromStr(txtDate); Calendar calendar = Calendar.getInstance(); calendar.setTime(date); String week = new SimpleDateFormat("EEEE").format(date); return week; } // 计算两个日期间的间隔天数 public long getDaysFromTwoDate(String txtDate1, String txtDate2) { if(txtDate1 == null || txtDate1.equals("")) { return 0; } if(txtDate2 == null || txtDate2.equals("")) { return 0; } SimpleDateFormat sDateFormat = new SimpleDateFormat("yyyy-MM-dd"); long days = 0; try { Date date1 = sDateFormat.parse(txtDate1); Date date2 = sDateFormat.parse(txtDate2); days = (date2.getTime() - date1.getTime())/(24*60*60*1000); // 通过getTime()方法，把时间Date转换成毫秒格式Long类型，进行计算 } catch (Exception e) { System.out.println(e.getMessage()); } return days; } }

运行结果：

当前日期： 

2012-03-07

2012-03-07 12:30:11

2012-3-7 12:30:11.101

计算周： 

-3

3/5/12 12:30 PM

3/10/12 12:30 PM

3/12/12 12:30 PM

3/3/12 12:30 PM

计算月： 

2012-03-01

2012-03-31

2012-02-01

2012-02-29

2012-04-01

2012-04-30

计算年： 

2012-01-01

2012-12-31

2011-01-01

2011-12-31

2013-01-01

2013-12-31

366 in 2012

计算季度： 

2012-3-7 in [ 2012-1 : 2012-3 ]

31 in [ 2012-3-7 ]

true

日期格式转换与计算： 

Wed Jun 20 00:00:00 CST 2012

Wednesday

2012-06-02 -> 2012-06-12间隔天数:10

参考推荐：