说明：这个工具类是从同事代码上拉取到的，大概也是来自他人，记录在册，小小工具类，可以省去很多烦恼。
代码：
package com.xfc.utils;// TODO import java.sql.Date; import java.sql.Timestamp; import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.Calendar; import java.util.List; /** * Time工具类 * * @author Anthony */ public class TimeUtils { public static final int DECEMBER = 12; // 12 months public static final String[] MONTHS = {"1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12"}; // months public static final long DAYMILLI = 24 * 60 * 60 * 1000; // the number of milliseconds in a day public static final long HOURMILLI = 60 * 60 * 1000; // the number of milliseconds in an hour public static final long MINUTEMILLI = 60 * 1000; // the number of milliseconds in a minute public static final long SECONDMILLI = 1000; // the number of milliseconds in a second public static final String DB_DATE_PATTERN_41 = "MM/dd"; public static final String DB_DATE_PATTERN_42 = "MM-dd"; public static final String DB_DATE_PATTERN_61 = "yyyy/MM"; public static final String DB_DATE_PATTERN_62 = "yyyy-MM"; public static final String DB_DATE_PATTERN_81 = "yyyy/MM/dd"; // date with format "/" public static final String DB_DATE_PATTERN_82 = "yyyy-MM-dd"; // date with format "-" public static final String DB_TIME_PATTERN_F1 = "yyyy/MM/dd HH:mm:ss"; // date format with "/" and time accurate to second public static final String DB_TIME_PATTERN_F2 = "yyyy-MM-dd HH:mm:ss"; // date with format "-" and time accurate to second public static final String DB_TIME_PATTERN_H1 = "yyyy/MM/dd HH:mm:ss.SSS"; // date format with "/" and time accurate to millisecond public static final String DB_TIME_PATTERN_H2 = "yyyy-MM-dd HH:mm:ss.SSS"; // date format with "-" and time accurate to millisecond public static final String DB_TIME_PATTERN_06 = "HH:mm:ss"; // time accurate to second public static final String DB_TIME_PATTERN_09 = "HH:mm:ss.SSS"; // time accurate to millisecond public static final String DATE_FMT_40 = "yyyy"; // unformatted year public static final String DATE_FMT_60 = "yyMMdd"; // unformatted (abbreviated year) date public static final String DATE_FMT_61 = "yyyyMM"; // unformatted year and month public static final String DATE_FMT_62 = "yyMMddHH"; // unformatted (abbreviated year) date and time accurate to hour public static final String DATE_FMT_64 = "yyMMddHHmm"; // unformatted (abbreviated year) date and time accurate to minute public static final String DATE_FMT_66 = "yyMMddHHmmss"; // unformatted (abbreviated year) date and time accurate to second public static final String DATE_FMT_69 = "yyMMddHHmmssSSS"; // unformatted (abbreviated year) date and time accurate to millisecond public static final String DATE_FMT_80 = "yyyyMMdd"; // unformatted year month and date public static final String DATE_FMT_86 = "yyyyMMddHHmmss"; // unformatted time accurate to second public static final String DATE_FMT_89 = "yyyyMMddHHmmssSSS"; // unformatted time accurate to millisecond public static final String DATE_FMT_04 = "HHmm"; // unformatted hour and minute public static final String DATE_FMT_06 = "HHmmss"; // unformatted hour minute and second public static final String DATE_FMT_28 = "ddHHmmss"; // unformatted date hour minute and second /** * To format the current time * * @param sFmtTo * @return */ public static String formatDate(String sFmtTo) { try { SimpleDateFormat formatter = new SimpleDateFormat(sFmtTo); String sRet = formatter.format(new Date(System.currentTimeMillis())); return sRet; } catch (Exception ex) { return ""; } } /** * To format the time appointed * * @param sDate --> date string value * @param sFmtTo --> format style * @return */ public static String formatDate(Date sDate, String sFmtTo) { if (sDate == null || "".equals(sDate)) return ""; try { SimpleDateFormat sdfTo = new SimpleDateFormat(sFmtTo); return sdfTo.format(sDate); } catch (Exception ex) { return ""; } } /** * To format the time appointed * * @param sDate --> date string value * @param sFmtFrom -- > current format style * @param sFmtTo --> expected format style * @return */ public static String formatDate(String sDate, String sFmtFrom, String sFmtTo) { if (sDate == null || "".equals(sDate)) return ""; if (sFmtFrom.equals(sFmtTo)) return sDate; try { SimpleDateFormat sdfFrom = new SimpleDateFormat(sFmtFrom); java.util.Date dt = sdfFrom.parse(sDate); SimpleDateFormat sdfTo = new SimpleDateFormat(sFmtTo); return sdfTo.format(dt); } catch (Exception ex) { return sDate; } } /** * To count days * * @param fromDate --> beginning date * @param endDate --> ending date * @param sFmtFrom --> current date format style * @return */ public static long countDays(String fromDate, String endDate, String sFmtFrom) { Timestamp t1 = Timestamp.valueOf(formatDate(fromDate, sFmtFrom, DB_TIME_PATTERN_H2)); Timestamp t2 = Timestamp.valueOf(formatDate(endDate, sFmtFrom, DB_TIME_PATTERN_H2)); return (t2.getTime() - t1.getTime()) / DAYMILLI + 1; } /** * To count hours * * @param fromDate --> beginning date * @param endDate --> ending date * @param sFmtFrom --> current date format style * @return */ public static long countHours(String fromDate, String endDate, String sFmtFrom) { Timestamp t1 = Timestamp.valueOf(formatDate(fromDate, sFmtFrom, DB_TIME_PATTERN_H2)); Timestamp t2 = Timestamp.valueOf(formatDate(endDate, sFmtFrom, DB_TIME_PATTERN_H2)); return (t2.getTime() - t1.getTime()) / HOURMILLI + 1; } /** * To count minutes * * @param fromDate --> beginning date * @param endDate --> ending date * @param sFmtFrom --> current date format style * @return */ public static long countMinutes(String fromDate, String endDate, String sFmtFrom) { if (fromDate.trim() == "" || endDate.trim() == "") return 0; Timestamp t1 = Timestamp.valueOf(formatDate(fromDate, sFmtFrom, DB_TIME_PATTERN_H2)); Timestamp t2 = Timestamp.valueOf(formatDate(endDate, sFmtFrom, DB_TIME_PATTERN_H2)); return (t2.getTime() - t1.getTime()) / MINUTEMILLI + 1; } /** * To count seconds * * @param fromDate --> beginning date * @param endDate --> ending date * @param sFmtFrom --> current date format style * @return */ public static long countSeconds(String fromDate, String endDate, String sFmtFrom) { Timestamp t1 = Timestamp.valueOf(formatDate(fromDate, sFmtFrom, DB_TIME_PATTERN_H2)); Timestamp t2 = Timestamp.valueOf(formatDate(endDate, sFmtFrom, DB_TIME_PATTERN_H2)); return (t2.getTime() - t1.getTime()) / SECONDMILLI + 1; } /** * To count milliseconds * * @param fromDate --> beginning date * @param endDate --> ending date * @param sFmtFrom --> current date format style * @return */ public static long countMillions(String fromDate, String endDate, String sFmtFrom) { Timestamp t1 = Timestamp.valueOf(formatDate(fromDate, sFmtFrom, DB_TIME_PATTERN_H2)); Timestamp t2 = Timestamp.valueOf(formatDate(endDate, sFmtFrom, DB_TIME_PATTERN_H2)); return t2.getTime() - t1.getTime() + 1; } /** * 给定的时间加上固定的年 * * @param years * @param sFmtTo * @return */ public static String addYears(int years, String sFmtTo) { String date = ""; try { SimpleDateFormat dateFormat = new SimpleDateFormat(sFmtTo); Calendar calendar = dateFormat.getCalendar(); calendar.setTime(new Date(System.currentTimeMillis())); calendar.set(Calendar.YEAR, calendar.get(Calendar.YEAR) + years); date = dateFormat.format(calendar.getTime()); } catch (Exception ex) { } return date; } /** * 给定的时间加上固定的年 * * @param date * @param years * @param sFmtFrom * @return */ public static String addYears(String date, int years, String sFmtFrom) { if (date == null || date.equals("")) return date; if (years == 0) return date; try { SimpleDateFormat dateFormat = new SimpleDateFormat(sFmtFrom); Calendar calendar = dateFormat.getCalendar(); calendar.setTime(dateFormat.parse(date)); calendar.set(Calendar.YEAR, calendar.get(Calendar.YEAR) + years); date = dateFormat.format(calendar.getTime()); } catch (Exception ex) { } return date; } /** * 给定的时间加上固定的月 * * @param months * @param sFmtTo * @return */ public static String addMonths(int months, String sFmtTo) { String date = ""; try { SimpleDateFormat dateFormat = new SimpleDateFormat(sFmtTo); Calendar calendar = dateFormat.getCalendar(); calendar.setTime(new Date(System.currentTimeMillis())); calendar.set(Calendar.MONTH, calendar.get(Calendar.MONTH) + months); date = dateFormat.format(calendar.getTime()); } catch (Exception ex) { } return date; } /** * 给定的时间加上固定的月 * * @param date * @param months * @param sFmtFrom * @return */ public static String addMonths(String date, int months, String sFmtFrom) { if (date == null || date.equals("")) return date; if (months == 0) return date; try { SimpleDateFormat dateFormat = new SimpleDateFormat(sFmtFrom); Calendar calendar = dateFormat.getCalendar(); calendar.setTime(dateFormat.parse(date)); calendar.set(Calendar.MONTH, calendar.get(Calendar.MONTH) + months); date = dateFormat.format(calendar.getTime()); } catch (Exception ex) { } return date; } /** * 当前时间加上固定的天 * * @param days * @param sFmtTo * @return */ public static String addDays(int days, String sFmtTo) { String date = ""; try { SimpleDateFormat dateFormat = new SimpleDateFormat(sFmtTo); Calendar calendar = dateFormat.getCalendar(); calendar.setTime(new Date(System.currentTimeMillis())); calendar.set(Calendar.DAY_OF_MONTH, calendar.get(Calendar.DAY_OF_MONTH) + days); date = dateFormat.format(calendar.getTime()); } catch (Exception ex) { } return date; } /** * 当前时间加上固定的天 * * @param date * @param days * @param sFmtFrom * @return */ public static String addDays(String date, int days, String sFmtFrom) { if ((date == null) || date.equals("")) return ""; if (days == 0) return date; try { SimpleDateFormat dateFormat = new SimpleDateFormat(sFmtFrom); Calendar calendar = dateFormat.getCalendar(); calendar.setTime(dateFormat.parse(date)); calendar.set(Calendar.DAY_OF_MONTH, calendar.get(Calendar.DAY_OF_MONTH) + days); date = dateFormat.format(calendar.getTime()); } catch (Exception ex) { } return date; } /** * 给定的时间加上固定的小时 * * @param date * @param hours * @param sFmtFrom * @return */ public static String addHours(String date, int hours, String sFmtFrom) { if ((date == null) || date.equals("")) return ""; if (hours == 0) return date; try { SimpleDateFormat dateFormat = new SimpleDateFormat(sFmtFrom); Calendar calendar = dateFormat.getCalendar(); calendar.setTime(dateFormat.parse(date)); calendar.set(Calendar.HOUR_OF_DAY, calendar.get(Calendar.HOUR_OF_DAY) + hours); date = dateFormat.format(calendar.getTime()); } catch (Exception ex) { } return date; } /** * 给定的时间加上固定的分钟 * * @param date * @param minutes * @param sFmtFrom * @return */ public static String addMinutes(String date, int minutes, String sFmtFrom) { if ((date == null) || date.equals("")) return ""; if (minutes == 0) return date; try { SimpleDateFormat dateFormat = new SimpleDateFormat(sFmtFrom); Calendar calendar = dateFormat.getCalendar(); calendar.setTime(dateFormat.parse(date)); calendar.set(Calendar.MINUTE, calendar.get(Calendar.MINUTE) + minutes); date = dateFormat.format(calendar.getTime()); } catch (Exception ex) { } return date; } public static String addSeconds(String date, int seconds, String sFmtFrom) { if ((date == null) || date.equals("")) return ""; if (seconds == 0) return date; try { SimpleDateFormat dateFormat = new SimpleDateFormat(sFmtFrom); Calendar calendar = dateFormat.getCalendar(); calendar.setTime(dateFormat.parse(date)); calendar.set(Calendar.SECOND, calendar.get(Calendar.SECOND) + seconds); date = dateFormat.format(calendar.getTime()); } catch (Exception ex) { } return date; } /** * 返回一周的第几天 * * @return 1-7的一个数、如果失败则返回-1 */ public static int getDayOFWeak(String date, String sFmtFrom) { if ((date == null) || (date.equals(""))) return -1; try { SimpleDateFormat dateFormat = new SimpleDateFormat(sFmtFrom); Calendar calendar = dateFormat.getCalendar(); calendar.setTime(dateFormat.parse(date)); return calendar.get(Calendar.DAY_OF_WEEK); } catch (Exception ex) { return -1; } } /** * 返回一年的第几周 * * @return 1-52的一个数、如果失败返回-1 */ public static int getWeekOfYear(String date, String sFmtFrom) { if ((date == null) || date.equals("")) return -1; try { SimpleDateFormat dateFormat = new SimpleDateFormat(sFmtFrom); Calendar calendar = dateFormat.getCalendar(); calendar.setTime(dateFormat.parse(date)); return calendar.get(Calendar.WEEK_OF_YEAR); } catch (Exception ex) { return -1; } } /** * 返回一个月的天数 * * @param year * @param month * @return */ public static int getMonthLength(int year, int month) { if (month == 2) { if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) return 29; else return 28; } if (month == 4 || month == 6 || month == 9 || month == 11) return 30; else return 31; } /** * 返回上个月的最后一天 * * @param date61 * @return DATE_FMT_80 */ public static String getLastMonEndDay(String date61) { return addDays(date61 + "01", -1, DATE_FMT_80); } /** * 返回下个月的头一天 * * @param date61 * @return DATE_FMT_80 */ public static String getNextMonBeginDay(String date61) { return addMonths(date61, 1, DATE_FMT_61) + "01"; } /** * 取得一年的月份列表 * * @return [1.2.3......12] */ public static List<String> getYearMonthList() { List<String> monthList = new ArrayList<String>(); for (int i = 1; i < 13; i++) monthList.add(String.valueOf(i)); return monthList; } /** * 取得当前日期的某个位置的值，如年、月、日等等 * * @param descFmt * @return */ public static int getSingleTime(String descFmt) { Calendar instance = Calendar.getInstance(); if (descFmt.equals("Y")) return instance.get(Calendar.YEAR); else if (descFmt.equals("M")) return instance.get(Calendar.MONTH) + 1; else if (descFmt.equals("dd")) return instance.get(Calendar.DAY_OF_MONTH); else if (descFmt.equals("d")) return instance.get(Calendar.DAY_OF_WEEK); else if (descFmt.equals("HH")) return instance.get(Calendar.HOUR_OF_DAY); else if (descFmt.equals("H")) return instance.get(Calendar.HOUR); else if (descFmt.equals("m")) return instance.get(Calendar.MINUTE); else if (descFmt.equals("s")) return instance.get(Calendar.SECOND); else if (descFmt.equals("S")) return instance.get(Calendar.MILLISECOND); return 0; } public static int getSingleTime(String date, String sFmtFrom, String descFmt) { SimpleDateFormat dateFormat = new SimpleDateFormat(sFmtFrom); Calendar instance = dateFormat.getCalendar(); try { instance.setTime(dateFormat.parse(date)); } catch (Exception ex) { return 0; } if (descFmt.equals("Y")) return instance.get(Calendar.YEAR); else if (descFmt.equals("M")) return instance.get(Calendar.MONTH) + 1; else if (descFmt.equals("dd")) return instance.get(Calendar.DAY_OF_MONTH); else if (descFmt.equals("d")) return instance.get(Calendar.DAY_OF_WEEK); else if (descFmt.equals("HH")) return instance.get(Calendar.HOUR_OF_DAY); else if (descFmt.equals("H")) return instance.get(Calendar.HOUR); else if (descFmt.equals("m")) return instance.get(Calendar.MINUTE); else if (descFmt.equals("s")) return instance.get(Calendar.SECOND); else if (descFmt.equals("S")) return instance.get(Calendar.MILLISECOND); return 0; } /** * 判断是否为闰年 * * @param year * @return */ public static boolean isLeapYear(int year) { if (year % 100 != 0 && year % 4 == 0) return true; else if (year % 400 == 0) return true; return false; } /** * 连接年月日形成日期形式 * * @param year * @param month * @param day * @param partten * @return */ public static String dateJoin(String year, String month, String day, String partten) { String date = (year == null) ? "" : year; if (month != null) { date = date + partten + ((month.length() == 1) ? "0" + month : month); if (day != null) date = date + partten + ((day.length() == 1) ? "0" + day : day); } return date; } /** * 判断给定的日期是否在范围内，前闭后开 * * @param date * @param fromDate * @param endDate * @return */ public static boolean dateBetween(String date, String fromDate, String endDate) { if (date.compareTo(fromDate) < 0) return false; if (date.compareTo(endDate) >= 0) return false; return true; } /** * 时间差，返回字串格式 * * @param fromDate * @param endDate * @param sFmtFrom * @return ?d?h?min?s */ public static String dateDiff(String fromDate, String endDate, String sFmtFrom) { Timestamp t1 = Timestamp.valueOf(formatDate(fromDate, sFmtFrom, DB_TIME_PATTERN_H2)); Timestamp t2 = Timestamp.valueOf(formatDate(endDate, sFmtFrom, DB_TIME_PATTERN_H2)); long between = (t2.getTime() - t1.getTime()); long day = between / DAYMILLI; long hour = between % DAYMILLI / HOURMILLI; long minute = between % HOURMILLI / MINUTEMILLI; long second = between % MINUTEMILLI / SECONDMILLI; return day + "d" + hour + "h" + minute + "min" + second + "s"; } /** * 按照指定的时间格式来格式化当前时间 * * @param date --> 待格式化的时间 (yyyy-mm-dd hh:mm:ss.fffffffff) * @param sFmtTo --> 时间格式 * @return 当前时间 */ public static String getFormatTime(Timestamp date, String sFmtTo) { if (date == null) return null; try { SimpleDateFormat formatter = new SimpleDateFormat(sFmtTo); String sRet = formatter.format(date); return sRet; } catch (Exception ex) { return ""; } } /** * 按照指定的格式来格式化当前的时间 * * @return Timestamp */ public static Timestamp toSqlTimestamp() { return Timestamp.valueOf(formatDate(DB_TIME_PATTERN_F2)); } /** * 按照指定的格式来格式化指定的时间 * * @param date --> 待格式化的时间 * @param sFmtFrom --> 时间格式 * @return Timestamp */ public static Timestamp toSqlTimestamp(String date, String sFmtFrom) { if (date == null || "".equals(date)) return null; try { return Timestamp.valueOf(formatDate(date, sFmtFrom, DB_TIME_PATTERN_F2)); } catch (Exception ex) { return null; } } public static boolean judgmentTimeFormat(String date, String sFmtFrom) { boolean convertSuccess = true; // 指定日期格式为四位年/两位月份/两位日期，注意yyyy/MM/dd区分大小写； SimpleDateFormat format = new SimpleDateFormat(sFmtFrom); try { // 设置lenient为false. // 否则SimpleDateFormat会比较宽松地验证日期，比如2007/02/29会被接受，并转换成2007/03/01 format.setLenient(false); format.parse(date); } catch (ParseException e) { // e.printStackTrace(); // 如果throw java.text.ParseException或者NullPointerException，就说明格式不对 convertSuccess = false; } return convertSuccess; } public static String formatDateByLong(String recognitionTime) { Long dateLong = Long.valueOf(recognitionTime); String format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date(dateLong)); return format; } /** * method Main() for test */ public static void main(String[] args) { // System.out.println(TimeUtils.addYears("2013-03-01", -2, // TimeUtils.DB_DATE_PATTERN_82)); // System.out.println(TimeUtils.dateDiff("2012-09-18 10:11:23", // "2012-09-19 10:13:48", TimeUtils.DB_TIME_PATTERN_F2)); // System.out.println(TimeUtils.getSingleTime("2016-05-08", // TimeUtils.DB_DATE_PATTERN_82, "dd")); System.out.println("2016-05-20".compareTo("2016-05-10 10:10:10")); System.out.println("2016-05-20".compareTo("2016-05-30 10:10:10")); } }