package com.netcode.date; import java.text.DateFormat;import java.text.ParseException;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;import java.util.GregorianCalendar;import java.util.TimeZone;/*** 日期类型与字符串类型相互转换*/public class DateUtil{ /** * Base ISO 8601 Date format yyyyMMdd i.e., 20021225 for the 25th day of December in the year 2002 */ public static final String ISO_DATE_FORMAT = "yyyyMMdd"; /** * Expanded ISO 8601 Date format yyyy-MM-dd i.e., 2002-12-25 for the 25th day of December in the year 2002 */ public static final String ISO_EXPANDED_DATE_FORMAT = "yyyy-MM-dd"; /** * yyyy-MM-dd hh:mm:ss */ public static String DATETIME_PATTERN = "yyyy-MM-dd hh:mm:ss"; /** * Default lenient setting for getDate. */ private static boolean LENIENT_DATE = false; /** * 暂时不用 * @param JD * @return */ protected static final float normalizedJulian(float JD) { float f = Math.round(JD + 0.5f) - 0.5f; return f; } /** * 浮点值转换成日期格式<br> * 暂时不用 * Returns the Date from a julian. The Julian date will be converted to noon GMT, * such that it matches the nearest half-integer (i.e., a julian date of 1.4 gets * changed to 1.5, and 0.9 gets changed to 0.5.) * * @param JD the Julian date * @return the Gregorian date */ public static final Date toDate(float JD) { /* To convert a Julian Day Number to a Gregorian date, assume that it is for 0 hours, Greenwich time (so * that it ends in 0.5). Do the following calculations, again dropping the fractional part of all * multiplicatons and divisions. Note: This method will not give dates accurately on the * Gregorian Proleptic Calendar, i.e., the calendar you get by extending the Gregorian * calendar backwards to years earlier than 1582. using the Gregorian leap year * rules. In particular, the method fails if Y<400. */ float Z = (normalizedJulian(JD)) + 0.5f; float W = (int) ( (Z - 1867216.25f) / 36524.25f); float X = (int) (W / 4f); float A = Z + 1 + W - X; float B = A + 1524; float C = (int) ( (B - 122.1) / 365.25); float D = (int) (365.25f * C); float E = (int) ( (B - D) / 30.6001); float F = (int) (30.6001f * E); int day = (int) (B - D - F); int month = (int) (E - 1); if (month > 12) { month = month - 12; } int year = (int) (C - 4715); //(if Month is January or February) or C-4716 (otherwise) if (month > 2) { year--; } Calendar c = Calendar.getInstance(); c.set(Calendar.YEAR, year); c.set(Calendar.MONTH, month - 1); // damn 0 offsets c.set(Calendar.DATE, day); return c.getTime(); } /** * Returns the days between two dates. Positive values indicate that * the second date is after the first, and negative values indicate, well, * the opposite. Relying on specific times is problematic. * * @param early the "first date" * @param late the "second date" * @return the days between the two dates */ public static final int daysBetween(Date early, Date late) { Calendar c1 = Calendar.getInstance(); Calendar c2 = Calendar.getInstance(); c1.setTime(early); c2.setTime(late); return daysBetween(c1, c2); } /** * Returns the days between two dates. Positive values indicate that * the second date is after the first, and negative values indicate, well, * the opposite. * * @param early * @param late * @return the days between two dates. */ public static final int daysBetween(Calendar early, Calendar late) { return (int) (toJulian(late) - toJulian(early)); } /** * Return a Julian date based on the input parameter. This is * based from calculations found at * <a href="http://quasar.as.utexas.edu/BillInfo/JulianDatesG.html">Julian Day Calculations * (Gregorian Calendar)</a>, provided by Bill Jeffrys. * @param c a calendar instance * @return the julian day number */ public static final float toJulian(Calendar c) { int Y = c.get(Calendar.YEAR); int M = c.get(Calendar.MONTH); int D = c.get(Calendar.DATE); int A = Y / 100; int B = A / 4; int C = 2 - A + B; float E = (int) (365.25f * (Y + 4716)); float F = (int) (30.6001f * (M + 1)); float JD = C + D + E + F - 1524.5f; return JD; } /** * 暂时不用 * Return a Julian date based on the input parameter. This is * based from calculations found at * <a href="http://quasar.as.utexas.edu/BillInfo/JulianDatesG.html">Julian Day Calculations * (Gregorian Calendar)</a>, provided by Bill Jeffrys. * @param date * @return the julian day number */ public static final float toJulian(Date date) { Calendar c = Calendar.getInstance(); c.setTime(date); return toJulian(c); } /** * 日期增加 * @param isoString 日期字符串 * @param fmt 格式 * @param field 年/月/日 Calendar.YEAR/Calendar.MONTH/Calendar.DATE * @param amount 增加数量 * @return * @throws ParseException */ public static final String dateIncrease(String isoString, String fmt, int field, int amount) { try { Calendar cal = GregorianCalendar.getInstance(TimeZone.getTimeZone( "GMT")); cal.setTime(stringToDate(isoString, fmt, true)); cal.add(field, amount); return dateToString(cal.getTime(), fmt); } catch (Exception ex) { return null; } } /** * Time Field Rolling function. * Rolls (up/down) a single unit of time on the given time field. * * @param isoString * @param field the time field. * @param up Indicates if rolling up or rolling down the field value. * @param expanded use formating char's * @exception ParseException if an unknown field value is given. */ public static final String roll(String isoString, String fmt, int field, boolean up) throws ParseException { Calendar cal = GregorianCalendar.getInstance(TimeZone.getTimeZone( "GMT")); cal.setTime(stringToDate(isoString, fmt)); cal.roll(field, up); return dateToString(cal.getTime(), fmt); } /** * Time Field Rolling function. * Rolls (up/down) a single unit of time on the given time field. * * @param isoString * @param field the time field. * @param up Indicates if rolling up or rolling down the field value. * @exception ParseException if an unknown field value is given. */ public static final String roll(String isoString, int field, boolean up) throws ParseException { return roll(isoString, DATETIME_PATTERN, field, up); } /** * 字符串转换为日期java.util.Date * @param dateText 字符串 * @param format 日期格式 * @param lenient 日期越界标志 * @return */ public static Date stringToDate(String dateText, String format, boolean lenient) { if (dateText == null) { return null; } DateFormat df = null; try { if (format == null) { df = new SimpleDateFormat(); } else { df = new SimpleDateFormat(format); } // setLenient avoids allowing dates like 9/32/2001 // which would otherwise parse to 10/2/2001 df.setLenient(false); return df.parse(dateText); } catch (ParseException e) { return null; } } /** * 字符串转换为日期java.util.Date * @param dateText 字符串 * @param format 日期格式 * @return */ public static Date stringToDate(String dateString, String format) { return stringToDate(dateString, format, LENIENT_DATE); } /** * 字符串转换为日期java.util.Date * @param dateText 字符串 */ public static Date stringToDate(String dateString) { return stringToDate(dateString, ISO_EXPANDED_DATE_FORMAT, LENIENT_DATE); } /** 根据时间变量返回时间字符串 * @return 返回时间字符串 * @param pattern 时间字符串样式 * @param date 时间变量 */ public static String dateToString(Date date, String pattern) { if (date == null) { return null; } try { SimpleDateFormat sfDate = new SimpleDateFormat(pattern); sfDate.setLenient(false); return sfDate.format(date); } catch (Exception e) { return null; } } /** * 根据时间变量返回时间字符串 yyyy-MM-dd * @param date * @return */ public static String dateToString(Date date) { return dateToString(date, ISO_EXPANDED_DATE_FORMAT); } /** 返回当前时间 * @return 返回当前时间 */ public static Date getCurrentDateTime() { java.util.Calendar calNow = java.util.Calendar.getInstance(); java.util.Date dtNow = calNow.getTime(); return dtNow; } /** * 返回当前日期字符串 * @param pattern 日期字符串样式 * @return */ public static String getCurrentDateString(String pattern) { return dateToString(getCurrentDateTime(), pattern); } /** * 返回当前日期字符串 yyyy-MM-dd * @return */ public static String getCurrentDateString() { return dateToString(getCurrentDateTime(), ISO_EXPANDED_DATE_FORMAT); } /** * 返回当前日期+时间字符串 yyyy-MM-dd hh:mm:ss * @param date * @return */ public static String dateToStringWithTime(Date date) { return dateToString(date, DATETIME_PATTERN); } /** * 日期增加-按日增加 * @param date * @param days * @return java.util.Date */ public static Date dateIncreaseByDay(Date date, int days) { Calendar cal = GregorianCalendar.getInstance(TimeZone.getTimeZone( "GMT")); cal.setTime(date); cal.add(Calendar.DATE, days); return cal.getTime(); } /** * 日期增加-按月增加 * @param date * @param days * @return java.util.Date */ public static Date dateIncreaseByMonth(Date date, int mnt) { Calendar cal = GregorianCalendar.getInstance(TimeZone.getTimeZone( "GMT")); cal.setTime(date); cal.add(Calendar.MONTH, mnt); return cal.getTime(); } /** * 日期增加-按年增加 * @param date * @param mnt * @return java.util.Date */ public static Date dateIncreaseByYear(Date date, int mnt) { Calendar cal = GregorianCalendar.getInstance(TimeZone.getTimeZone( "GMT")); cal.setTime(date); cal.add(Calendar.YEAR, mnt); return cal.getTime(); } /** * 日期增加 * @param date 日期字符串 yyyy-MM-dd * @param days * @return 日期字符串 yyyy-MM-dd */ public static String dateIncreaseByDay(String date, int days) { return dateIncreaseByDay(date, ISO_DATE_FORMAT, days); } /** * 日期增加 * @param date 日期字符串 * @param fmt 日期格式 * @param days * @return */ public static String dateIncreaseByDay(String date, String fmt, int days) { return dateIncrease(date, fmt, Calendar.DATE, days); } /** * 日期字符串格式转换 * @param src 日期字符串 * @param srcfmt 源日期格式 * @param desfmt 目标日期格式 * @return */ public static String stringToString(String src, String srcfmt, String desfmt) { return dateToString(stringToDate(src, srcfmt), desfmt); }}
