日期处理 java——转载
package com.icinfo.hxbusi.synch.client.task; import java.text.ParsePosition;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;import java.util.Locale; public class DateUtils { // 静态常量 public static final String C_TIME_PATTON_DEFAULT = "yyyy-MM-dd HH:mm:ss"; public static final String C_DATE_PATTON_DEFAULT = "yyyy-MM-dd"; public static final int C_ONE_SECOND = 1000; public static final int C_ONE_MINUTE = 60 * C_ONE_SECOND; public static final long C_ONE_HOUR = 60 * C_ONE_MINUTE; public static final long C_ONE_DAY = 24 * C_ONE_HOUR; // 计算当前月份的最大天数 public static int findMaxDayInMonth() { return findMaxDayInMonth(0, 0); } //计算指定日期月份的最大天数 public static int findMaxDayInMonth(Date date) { if (date == null) { return 0; } return findMaxDayInMonth(date2Calendar(date)); } // 计算指定日历月份的最大天数 public static int findMaxDayInMonth(Calendar calendar) { if (calendar == null) { return 0; } return calendar.getActualMaximum(Calendar.DAY_OF_MONTH); } // 计算当前年某月份的最大天数 public static int findMaxDayInMonth(int month) { return findMaxDayInMonth(0, month); } // 计算某年某月份的最大天数 public static int findMaxDayInMonth(int year, int month) { Calendar calendar = Calendar.getInstance(); if (year > 0) { calendar.set(Calendar.YEAR, year); } if (month > 0) { calendar.set(Calendar.MONTH, month - 1); } return findMaxDayInMonth(calendar); } // Calendar 转换为 Date public static Date calendar2Date(Calendar calendar) { if (calendar == null) { return null; } return calendar.getTime(); } // Date 转换为 Calendar public static Calendar date2Calendar(Date date) { if (date == null) { return null; } Calendar calendar = Calendar.getInstance(); calendar.setTime(date); return calendar; } // 拿到默认格式的SimpleDateFormat public static SimpleDateFormat getSimpleDateFormat() { return getSimpleDateFormat(null); } // 拿到指定输出格式的SimpleDateFormat public static SimpleDateFormat getSimpleDateFormat(String format) { SimpleDateFormat sdf; if (format == null) { sdf = new SimpleDateFormat(C_TIME_PATTON_DEFAULT); } else { sdf = new SimpleDateFormat(format); } return sdf; } // 转换当前时间为默认格式 public static String formatDate2Str() { return formatDate2Str(new Date()); } // 转换指定时间为默认格式 publicstatic String formatDate2Str(Date date) { return formatDate2Str(date, C_TIME_PATTON_DEFAULT); } // 转换指定时间为指定格式 public static String formatDate2Str(Date date, String format) { if (date == null) { return null; } if (format == null || format.equals("")) { format = C_TIME_PATTON_DEFAULT; } SimpleDateFormat sdf = getSimpleDateFormat(format); return sdf.format(date); } // 转换默认格式的时间为Date public static Date formatStr2Date(String dateStr) { return formatStr2Date(dateStr, null); } // 转换指定格式的时间为Date public static Date formatStr2Date(String dateStr, String format) { if (dateStr == null) { return null; } if (format == null || format.equals("")) { format = C_TIME_PATTON_DEFAULT; } SimpleDateFormat sdf = getSimpleDateFormat(format); return sdf.parse(dateStr, new ParsePosition(0)); } // 转换默认格式的时间为指定格式时间 public static String formatDefault2Define(String dateStr, String defineFormat) { return formatSource2Target(dateStr, C_TIME_PATTON_DEFAULT, defineFormat); } // 转换源格式的时间为目标格式时间 public static String formatSource2Target(String dateStr, String sourceFormat, String targetFormat) { Date date = formatStr2Date(dateStr, sourceFormat); return formatDate2Str(date, targetFormat); } // 计算当天是该年中的第几周 public static int findWeeksNoInYear() { return findWeeksNoInYear(new Date()); } // 计算指定日期是该年中的第几周 public static int findWeeksNoInYear(Date date) { if (date == null) { return 0; } return findWeeksNoInYear(date2Calendar(date)); } // 计算指定日历是该年中的第几周 public static int findWeeksNoInYear(Calendar calendar) { if (calendar == null) { return 0; } return calendar.get(Calendar.WEEK_OF_YEAR); } //计算一年中的第几星期是几号 public static Date findDateInWeekOnYear(int year, int weekInYear, int dayInWeek) { Calendar calendar = Calendar.getInstance(); if (year > 0) { calendar.set(Calendar.YEAR, year); } calendar.set(Calendar.WEEK_OF_YEAR, weekInYear); calendar.set(Calendar.DAY_OF_WEEK, dayInWeek); return calendar.getTime(); } // 相对于当前日期的前几天(days < 0０００００)或者后几天(days > 0) public static Date dayBefore2Date(int days) { Date date = new Date(); return dayBefore2Object(days, null, date); } // 相对于当前日期的前几天(days < 0０００００)或者后几天(days > 0) public static String dayBefore2Str(int days) { String string = formatDate2Str(); return dayBefore2Object(days, null, string); } // 相对于当前日期的前几天(days < 0０００００)或者后几天(days > 0) @SuppressWarnings("unchecked") public static <T extends Object> T dayBefore2Object(int days, String format, T instance) { Calendar calendar = Calendar.getInstance(); if (days == 0) { return null; } if (format == null || format.equals("")) { format = C_TIME_PATTON_DEFAULT; } calendar.add(Calendar.DATE, days); if (instance instanceof Date) { return (T)calendar.getTime(); } else if (instance instanceof String) { return (T)formatDate2Str(calendar2Date(calendar), format); } return null; } // 相对于指定日期的前几天(days < 0０００００)或者后几天(days > 0) public static Date defineDayBefore2Date(Date date, int days) { Date dateInstance = new Date(); return defineDayBefore2Object(date, days, null, dateInstance); } // 相对于指定日期的前几天(days < 0０００００)或者后几天(days > 0) public static String defineDayBefore2Str(Date date, int days) { String stringInstance = formatDate2Str(); return defineDayBefore2Object(date, days, null, stringInstance); } // 相对于指定日期的前几天(days < 0０００００)或者后几天(days > 0) @SuppressWarnings("unchecked") public static <T extends Object> T defineDayBefore2Object(Date date, int days, String format, T instance) { if (date == null || days == 0) { return null; } if (format == null || format.equals("")) { format = C_TIME_PATTON_DEFAULT; } Calendar calendar = date2Calendar(date); calendar.add(Calendar.DATE, days); if (instance instanceof Date) { return (T)calendar.getTime(); } else if (instance instanceof String) { return (T)formatDate2Str(calendar2Date(calendar), format); } return null; } // 相对于当前日期的前几月(months < 0０００００)或者后几月(months > 0)时间 public static Date monthBefore2Date(int months) { Date date = new Date(); return monthBefore2Object(months, null, date); } // 相对于当前日期的前几月(months < 0０００００)或者后几月(months > 0)时间 public static String monthBefore2Str(int months) { String string = formatDate2Str(); return monthBefore2Object(months, null, string); } // 相对于当前日期的前几月(months < 0０００００)或者后几月(months > 0)时间 @SuppressWarnings("unchecked") public static <T extends Object> T monthBefore2Object(int months, String format, T instance) { if (months == 0) { return null; } if (format == null || format.equals("")) { format = C_TIME_PATTON_DEFAULT; } Calendar calendar = Calendar.getInstance(); calendar.add(Calendar.MONTH, months); if (instance instanceof Date) { return (T)calendar.getTime(); } else if (instance instanceof String) { return (T)formatDate2Str(calendar2Date(calendar), format); } return null; } // 相对于指定日期的前几月(months < 0０００００)或者后几月(months > 0)时间 public static Date defineMonthBefore2Date(Date date, int months) { Date dateInstance = new Date(); return defineMonthBefore2Object(date, months, null, dateInstance); } // 相对于指定日期的前几月(months < 0０００００)或者后几月(months > 0)时间 public static String defineMonthBefore2Str(Date date, int months) { String stringInstance = formatDate2Str(); return defineMonthBefore2Object(date, months, null, stringInstance); } // 相对于指定日期的前几月(months < 0０００００)或者后几月(months > 0)时间 @SuppressWarnings("unchecked") public static <T extends Object> T defineMonthBefore2Object(Date date, int months, String format, T instance) { if (months == 0) { return null; } if (format == null || format.equals("")) { format = C_TIME_PATTON_DEFAULT; } Calendar calendar = date2Calendar(date); calendar.add(Calendar.MONTH, months); if (instance instanceof Date) { return (T)calendar.getTime(); } else if (instance instanceof String) { return (T)formatDate2Str(calendar2Date(calendar), format); } return null; } // 计算两个日期直接差的天数 public static int caculate2Days(Date firstDate, Date secondDate) { Calendar calendar = Calendar.getInstance(); calendar.setTime(firstDate); int dayNum1 = calendar.get(Calendar.DAY_OF_YEAR); calendar.setTime(secondDate); int dayNum2 = calendar.get(Calendar.DAY_OF_YEAR); return Math.abs(dayNum1 - dayNum2); } // 计算两个日期直接差的天数 public static int caculate2Days(Calendar firstCalendar, Calendar secondCalendar) { if (firstCalendar.after(secondCalendar)) { Calendar calendar = firstCalendar; firstCalendar = secondCalendar; secondCalendar = calendar; } long calendarNum1 = firstCalendar.getTimeInMillis(); long calendarNum2 = secondCalendar.getTimeInMillis(); return Math.abs((int)((calendarNum1 - calendarNum2)/C_ONE_DAY)); } public static void main(String[] args) {// System.out.println("当前月份的最大天数:" + findMaxDayInMonth(new Date()));// System.out.println("6月份的最大天数:" + findMaxDayInMonth(6));// System.out.println("1999-02月份的最大天数:" + findMaxDayInMonth(1999, 2));// System.out.println("2000-02月份的最大天数:" + findMaxDayInMonth(2000, 2)); // System.out.println(formatSource2Target("2009-07-24 11:02:35", null, "yyyy/MM/dd"));// System.out.println(findWeeksNoInYear()); // System.out.println("2003年的第30个星期一是那天:" + findDateInWeekOnYear(2003, 30, Calendar.MONDAY));// System.out.println("2009年的第30个星期一是那天:" + findDateInWeekOnYear(2009, 30, Calendar.FRIDAY)); // System.out.println("【日期格式】当前日期的前7天是:" + dayBefore2Date(-7));// System.out.println("【字符格式】当前日期的前7天是:" + dayBefore2Str(-7));// System.out.println("【日期格式】当前日期的后7天是:" + dayBefore2Date(7));// System.out.println("【字符格式】当前日期的后7天是:" + dayBefore2Str(7)); // System.out.println(formatStr2Date("2009-07-22", "yyyy-MM-dd")); // System.out.println("【日期格式】2009-07-22的前7天是:" + // defineDayBefore2Date(formatStr2Date("2009-07-22", "yyyy-MM-dd"), -7));// System.out.println("【字符格式】2009-07-22的前7天是:" + // defineDayBefore2Str(formatStr2Date("2009-07-22", "yyyy-MM-dd"), -7));// System.out.println("【日期格式】2009-07-22的后7天是:" + // defineDayBefore2Date(formatStr2Date("2009-07-22", "yyyy-MM-dd"), 7));// System.out.println("【字符格式】2009-07-22的后7天是:" + // defineDayBefore2Str(formatStr2Date("2009-07-22", "yyyy-MM-dd"), 7)); // System.out.println("【日期格式】相对于当前时间的前2月日期是:" + monthBefore2Date(-2));// System.out.println("【字符格式】相对于当前时间的前2月日期是:" + monthBefore2Date(-2));// System.out.println("【日期格式】相对于当前时间的后2月日期是:" + monthBefore2Date(2));// System.out.println("【字符格式】相对于当前时间的后2月日期是:" + monthBefore2Date(2)); // System.out.println("【日期格式】2009-07-22的前2月日期是:" + // defineMonthBefore2Date(formatStr2Date("2009-07-22", "yyyy-MM-dd"), -2));// System.out.println("【字符格式】2009-07-22的前2月日期是:" +// defineMonthBefore2Date(formatStr2Date("2009-07-22", "yyyy-MM-dd"), -2));// System.out.println("【日期格式】2009-07-22的后2月日期是:" + // defineMonthBefore2Date(formatStr2Date("2009-07-22", "yyyy-MM-dd"), 2));// System.out.println("【字符格式】2009-07-22的后2月日期是:" + // defineMonthBefore2Date(formatStr2Date("2009-07-22", "yyyy-MM-dd"), 2)); // Date firstDate = formatStr2Date("2009-07-22", "yyyy-MM-dd");// Date secondDate = formatStr2Date("2009-07-18", "yyyy-MM-dd");// System.out.println(caculate2Days(firstDate, secondDate)); Calendar firstC = date2Calendar(formatStr2Date("2009-10-22", "yyyy-MM-dd")); Calendar secondC = date2Calendar(formatStr2Date("2009-07-18", "yyyy-MM-dd")); System.out.println(caculate2Days(firstC, secondC)); Calendar d1 = Calendar.getInstance(Locale.UK);d1.set(2008, 12, 7);for (int i = 1; i < 365; i++) { d1.add(Calendar.DATE, 1);// int year = d1.get(Calendar.YEAR);//获取年份// int month=d1.get(Calendar.MONTH);//获取月份// int day=d1.get(Calendar.DATE);//获取日// String jhrq = year+"-"+(month<10?"0"+month:month)+"-"+(day<10?"0"+day:day);System.out.println(defineDayBefore2Str(formatStr2Date("2009-07-22", "yyyy-MM-dd"), i)); }
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