web开发中公用组件的开发之一---------DateUtils
web开发中公用组件的开发之一---------DateUtils在web应用中我们经常要到用到对日期的操作
已经有很多的开源代码供选择，例如apache 就有
不是太复杂就是不太适合中国国情的，反正项目中很少用到apache的公用组件包
下面是我在web开发中常用的些方法操作
现简单列举出来，已示记念。
package com.chinadim.test.utils;import java.text.ParsePosition;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;/** * xxxxx * xxxxxx */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 * @return */public static int findMaxDayInMonth() {return findMaxDayInMonth(0, 0);}/** * 计算指定日期月份的最大天数 * @param date * @return */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 * @param calendar * @return */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 * @param month * @return */public static int findMaxDayInMonth(int month) {return findMaxDayInMonth(0, month);}/** * 计算某年某月份的最大天数 * @param year * @param month * @return */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 * @param calendar * @return */public static Date calendar2Date(Calendar calendar) {if (calendar == null) {return null;}return calendar.getTime();}/** * Date 转换为 Calendar * @param date * @return */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 * @return */public static SimpleDateFormat getSimpleDateFormat() {return getSimpleDateFormat(null);}/** * 拿到指定输出格式的SimpleDateFormat * @param format * @return */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 * @return */public static String formatDate2Str() {return formatDate2Str(new Date());}/** * 转换指定时间为默认格式 * @param date * @return */publicstatic String formatDate2Str(Date date) {return formatDate2Str(date, C_TIME_PATTON_DEFAULT);}/** * 转换指定时间为指定格式 * @param date * @param format * @return */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 * @param dateStr * @return */public static Date formatStr2Date(String dateStr) {return formatStr2Date(dateStr, null);}/** * 转换指定格式的时间为Date * @param dateStr * @param format * @return */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 * @param dateStr * @param defineFormat * @return */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 * @param dateStr * @param sourceFormat * @param targetFormat * @return */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 * @return */public static int findWeeksNoInYear() {return findWeeksNoInYear(new Date());}/** * 计算指定日期是该年中的第几周 * @param date * @return */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 * @param calendar * @return */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* @param year * @param weekInYear * @param dayInWeek * @return */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) * @param days * @return */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) * @param days * @return */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) * @param days * @param format * @param instance */@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) * @param date * @param days * @return */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) * @param date * @param days * @return */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) * @param <T> * @param date * @param days * @param format * @param instance * @return */@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 * @param months * @return */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 * @param months * @return */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 * @param <T> * @param months * @param format * @param instance */@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 * @param date * @param months * @return */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 * @param date * @param months * @return */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 * @param <T> * @param date * @param months * @param format * @param instance * @return */@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 * @param firstDate * @param secondDate * @return */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 * @param firstCalendar * @param secondCalendar * @return */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("2009-07-22", "yyyy-MM-dd"));Calendar secondC = date2Calendar(formatStr2Date("2009-07-18", "yyyy-MM-dd"));System.out.println(caculate2Days(firstC, secondC));}}
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先占个位 还未晚 手头还有事情 先记述到这里
后面后陆续的完成
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好了 最后都发布完了 欢迎讨论
坚持做一点点自己喜欢的事情 会慢慢的成为自己的事业
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