日期处理类

public class AbDateUtil {
    
    /** 时间日期格式化到年月日时分秒. */
    public static final String dateFormatYMDHMS = "yyyy-MM-dd HH:mm:ss";
    
    /** 时间日期格式化到年月日. */
    public static final String dateFormatYMD = "yyyy-MM-dd";
    
    /** 时间日期格式化到年月. */
    public static final String dateFormatYM = "yyyy-MM";
    
    /** 时间日期格式化到年月日时分. */
    public static final String dateFormatYMDHM = "yyyy-MM-dd HH:mm";
    
    /** 时间日期格式化到月日. */
    public static final String dateFormatMD = "MM/dd";
    
    /** 时分秒. */
    public static final String dateFormatHMS = "HH:mm:ss";
    
    /** 时分. */
    public static final String dateFormatHM = "HH:mm";
    
    /** 上午. */
    public static final String AM = "AM";

    /** 下午. */
    public static final String PM = "PM";


    /**
     * 描述：String类型的日期时间转化为Date类型.
     *
     * @param strDate String形式的日期时间
     * @param format 格式化字符串，如："yyyy-MM-dd HH:mm:ss"
     * @return Date Date类型日期时间
     */
    public static Date getDateByFormat(String strDate, String format) {
        SimpleDateFormat mSimpleDateFormat = new SimpleDateFormat(format);
        Date date = null;
        try {
            date = mSimpleDateFormat.parse(strDate);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return date;
    }
    
    /**
     * 描述：获取偏移之后的Date.
     * @param date 日期时间
     * @param calendarField Calendar属性，对应offset的值， 如(Calendar.DATE,表示+offset天,Calendar.HOUR_OF_DAY,表示＋offset小时)
     * @param offset 偏移(值大于0,表示+,值小于0,表示－)
     * @return Date 偏移之后的日期时间
     */
    public Date getDateByOffset(Date date,int calendarField,int offset) {
        Calendar c = new GregorianCalendar();
        try {
            c.setTime(date);
            c.add(calendarField, offset);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return c.getTime();
    }
    
    /**
     * 描述：获取指定日期时间的字符串(可偏移).
     *
     * @param strDate String形式的日期时间
     * @param format 格式化字符串，如："yyyy-MM-dd HH:mm:ss"
     * @param calendarField Calendar属性，对应offset的值， 如(Calendar.DATE,表示+offset天,Calendar.HOUR_OF_DAY,表示＋offset小时)
     * @param offset 偏移(值大于0,表示+,值小于0,表示－)
     * @return String String类型的日期时间
     */
    public static String getStringByOffset(String strDate, String format,int calendarField,int offset) {
        String mDateTime = null;
        try {
            Calendar c = new GregorianCalendar();
            SimpleDateFormat mSimpleDateFormat = new SimpleDateFormat(format);
            c.setTime(mSimpleDateFormat.parse(strDate));
            c.add(calendarField, offset);
            mDateTime = mSimpleDateFormat.format(c.getTime());
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return mDateTime;
    }
    
    /**
     * 描述：Date类型转化为String类型(可偏移).
     *
     * @param date the date
     * @param format the format
     * @param calendarField the calendar field
     * @param offset the offset
     * @return String String类型日期时间
     */
    public static String getStringByOffset(Date date, String format,int calendarField,int offset) {
        String strDate = null;
        try {
            Calendar c = new GregorianCalendar();
            SimpleDateFormat mSimpleDateFormat = new SimpleDateFormat(format);
            c.setTime(date);
            c.add(calendarField, offset);
            strDate = mSimpleDateFormat.format(c.getTime());
        } catch (Exception e) {
            e.printStackTrace();
        }
        return strDate;
    }
    

    /**
     * 描述：Date类型转化为String类型.
     *
     * @param date the date
     * @param format the format
     * @return String String类型日期时间
     */
    public static String getStringByFormat(Date date, String format) {
        SimpleDateFormat mSimpleDateFormat = new SimpleDateFormat(format);
        String strDate = null;
        try {
            strDate = mSimpleDateFormat.format(date);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return strDate;
    }
    
    /**
     * 描述：获取指定日期时间的字符串,用于导出想要的格式.
     *
     * @param strDate String形式的日期时间，必须为yyyy-MM-dd HH:mm:ss格式
     * @param format 输出格式化字符串，如："yyyy-MM-dd HH:mm:ss"
     * @return String 转换后的String类型的日期时间
     */
    public static String getStringByFormat(String strDate, String format) {
        String mDateTime = null;
        try {
            Calendar c = new GregorianCalendar();
            SimpleDateFormat mSimpleDateFormat = new SimpleDateFormat(dateFormatYMDHMS);
            c.setTime(mSimpleDateFormat.parse(strDate));
            SimpleDateFormat mSimpleDateFormat2 = new SimpleDateFormat(format);
            mDateTime = mSimpleDateFormat2.format(c.getTime());
        } catch (Exception e) {
            e.printStackTrace();
        }
        return mDateTime;
    }
    
    /**
     * 描述：获取milliseconds表示的日期时间的字符串.
     *
     * @param milliseconds the milliseconds
     * @param format  格式化字符串，如："yyyy-MM-dd HH:mm:ss"
     * @return String 日期时间字符串
     */
    public static String getStringByFormat(long milliseconds,String format) {
        String thisDateTime = null;
        try {
            SimpleDateFormat mSimpleDateFormat = new SimpleDateFormat(format);
            thisDateTime = mSimpleDateFormat.format(milliseconds);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return thisDateTime;
    }
    
    /**
     * 描述：获取表示当前日期时间的字符串.
     *
     * @param format  格式化字符串，如："yyyy-MM-dd HH:mm:ss"
     * @return String String类型的当前日期时间
     */
    public static String getCurrentDate(String format) {
        AbLogUtil.d(AbDateUtil.class, "getCurrentDate:"+format);
        String curDateTime = null;
        try {
            SimpleDateFormat mSimpleDateFormat = new SimpleDateFormat(format);
            Calendar c = new GregorianCalendar();
            curDateTime = mSimpleDateFormat.format(c.getTime());
        } catch (Exception e) {
            e.printStackTrace();
        }
        return curDateTime;

    }

    /**
     * 描述：获取表示当前日期时间的字符串(可偏移).
     *
     * @param format 格式化字符串，如："yyyy-MM-dd HH:mm:ss"
     * @param calendarField Calendar属性，对应offset的值， 如(Calendar.DATE,表示+offset天,Calendar.HOUR_OF_DAY,表示＋offset小时)
     * @param offset 偏移(值大于0,表示+,值小于0,表示－)
     * @return String String类型的日期时间
     */
    public static String getCurrentDateByOffset(String format,int calendarField,int offset) {
        String mDateTime = null;
        try {
            SimpleDateFormat mSimpleDateFormat = new SimpleDateFormat(format);
            Calendar c = new GregorianCalendar();
            c.add(calendarField, offset);
            mDateTime = mSimpleDateFormat.format(c.getTime());
        } catch (Exception e) {
            e.printStackTrace();
        }
        return mDateTime;

    }

    /**
     * 描述：计算两个日期所差的天数.
     *
     * @param milliseconds1 the milliseconds1
     * @param milliseconds2 the milliseconds2
     * @return int 所差的天数
     */
    public static int getOffectDay(long milliseconds1, long milliseconds2) {
        Calendar calendar1 = Calendar.getInstance();
        calendar1.setTimeInMillis(milliseconds1);
        Calendar calendar2 = Calendar.getInstance();
        calendar2.setTimeInMillis(milliseconds2);
        //先判断是否同年
        int y1 = calendar1.get(Calendar.YEAR);
        int y2 = calendar2.get(Calendar.YEAR);
        int d1 = calendar1.get(Calendar.DAY_OF_YEAR);
        int d2 = calendar2.get(Calendar.DAY_OF_YEAR);
        int maxDays = 0;
        int day = 0;
        if (y1 - y2 > 0) {
            maxDays = calendar2.getActualMaximum(Calendar.DAY_OF_YEAR);
            day = d1 - d2 + maxDays;
        } else if (y1 - y2 < 0) {
            maxDays = calendar1.getActualMaximum(Calendar.DAY_OF_YEAR);
            day = d1 - d2 - maxDays;
        } else {
            day = d1 - d2;
        }
        return day;
    }
    
    /**
     * 描述：计算两个日期所差的小时数.
     *
     * @param date1 第一个时间的毫秒表示
     * @param date2 第二个时间的毫秒表示
     * @return int 所差的小时数
     */
    public static int getOffectHour(long date1, long date2) {
        Calendar calendar1 = Calendar.getInstance();
        calendar1.setTimeInMillis(date1);
        Calendar calendar2 = Calendar.getInstance();
        calendar2.setTimeInMillis(date2);
        int h1 = calendar1.get(Calendar.HOUR_OF_DAY);
        int h2 = calendar2.get(Calendar.HOUR_OF_DAY);
        int h = 0;
        int day = getOffectDay(date1, date2);
        h = h1-h2+day*24;
        return h;
    }
    
    /**
     * 描述：计算两个日期所差的分钟数.
     *
     * @param date1 第一个时间的毫秒表示
     * @param date2 第二个时间的毫秒表示
     * @return int 所差的分钟数
     */
    public static int getOffectMinutes(long date1, long date2) {
        Calendar calendar1 = Calendar.getInstance();
        calendar1.setTimeInMillis(date1);
        Calendar calendar2 = Calendar.getInstance();
        calendar2.setTimeInMillis(date2);
        int m1 = calendar1.get(Calendar.MINUTE);
        int m2 = calendar2.get(Calendar.MINUTE);
        int h = getOffectHour(date1, date2);
        int m = 0;
        m = m1-m2+h*60;
        return m;
    }

    /**
     * 描述：获取本周一.
     *
     * @param format the format
     * @return String String类型日期时间
     */
    public static String getFirstDayOfWeek(String format) {
        return getDayOfWeek(format,Calendar.MONDAY);
    }

    /**
     * 描述：获取本周日.
     *
     * @param format the format
     * @return String String类型日期时间
     */
    public static String getLastDayOfWeek(String format) {
        return getDayOfWeek(format,Calendar.SUNDAY);
    }

    /**
     * 描述：获取本周的某一天.
     *
     * @param format the format
     * @param calendarField the calendar field
     * @return String String类型日期时间
     */
    private static String getDayOfWeek(String format,int calendarField) {
        String strDate = null;
        try {
            Calendar c = new GregorianCalendar();
            SimpleDateFormat mSimpleDateFormat = new SimpleDateFormat(format);
            int week = c.get(Calendar.DAY_OF_WEEK);
            if (week == calendarField){
                strDate = mSimpleDateFormat.format(c.getTime());
            }else{
                int offectDay = calendarField - week;
                if (calendarField == Calendar.SUNDAY) {
                    offectDay = 7-Math.abs(offectDay);
                } 
                c.add(Calendar.DATE, offectDay);
                strDate = mSimpleDateFormat.format(c.getTime());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return strDate;
    }
    
    /**
     * 描述：获取本月第一天.
     *
     * @param format the format
     * @return String String类型日期时间
     */
    public static String getFirstDayOfMonth(String format) {
        String strDate = null;
        try {
            Calendar c = new GregorianCalendar();
            SimpleDateFormat mSimpleDateFormat = new SimpleDateFormat(format);
            //当前月的第一天
            c.set(GregorianCalendar.DAY_OF_MONTH, 1);
            strDate = mSimpleDateFormat.format(c.getTime());
        } catch (Exception e) {
            e.printStackTrace();
        }
        return strDate;

    }

    /**
     * 描述：获取本月最后一天.
     *
     * @param format the format
     * @return String String类型日期时间
     */
    public static String getLastDayOfMonth(String format) {
        String strDate = null;
        try {
            Calendar c = new GregorianCalendar();
            SimpleDateFormat mSimpleDateFormat = new SimpleDateFormat(format);
            // 当前月的最后一天
            c.set(Calendar.DATE, 1);
            c.roll(Calendar.DATE, -1);
            strDate = mSimpleDateFormat.format(c.getTime());
        } catch (Exception e) {
            e.printStackTrace();
        }
        return strDate;
    }

    

    /**
     * 描述：获取表示当前日期的0点时间毫秒数.
     *
     * @return the first time of day
     */
    public static long getFirstTimeOfDay() {
            Date date = null;
            try {
                String currentDate = getCurrentDate(dateFormatYMD);
                date = getDateByFormat(currentDate+" 00:00:00",dateFormatYMDHMS);
                return date.getTime();
            } catch (Exception e) {
            }
            return -1;
    }
    
    /**
     * 描述：获取表示当前日期24点时间毫秒数.
     *
     * @return the last time of day
     */
    public static long getLastTimeOfDay() {
            Date date = null;
            try {
                String currentDate = getCurrentDate(dateFormatYMD);
                date = getDateByFormat(currentDate+" 24:00:00",dateFormatYMDHMS);
                return date.getTime();
            } catch (Exception e) {
            }
            return -1;
    }
    
    /**
     * 描述：判断是否是闰年()
     * <p>(year能被4整除 并且 不能被100整除) 或者 year能被400整除,则该年为闰年.
     *
     * @param year 年代（如2012）
     * @return boolean 是否为闰年
     */
    public static boolean isLeapYear(int year) {
        if ((year % 4 == 0 && year % 400 != 0) || year % 400 == 0) {
            return true;
        } else {
            return false;
        }
    }
    
    /**
     * 描述：根据时间返回格式化后的时间的描述.
     * 小于1小时显示多少分钟前  大于1小时显示今天＋实际日期，大于今天全部显示实际时间
     *
     * @param strDate the str date
     * @param outFormat the out format
     * @return the string
     */
    public static String formatDateStr2Desc(String strDate,String outFormat) {
        
        DateFormat df = new SimpleDateFormat(dateFormatYMDHMS);
        Calendar c1 = Calendar.getInstance();
        Calendar c2 = Calendar.getInstance();
        try {
            c2.setTime(df.parse(strDate));
            c1.setTime(new Date());
            int d = getOffectDay(c1.getTimeInMillis(), c2.getTimeInMillis());
            if(d==0){
                int h = getOffectHour(c1.getTimeInMillis(), c2.getTimeInMillis());
                if(h>0){
                    return "今天"+getStringByFormat(strDate,dateFormatHM);
                    //return h + "小时前";
                }else if(h<0){
                    //return Math.abs(h) + "小时后";
                }else if(h==0){
                    int m = getOffectMinutes(c1.getTimeInMillis(), c2.getTimeInMillis());
                    if(m>0){
                        return m + "分钟前";
                    }else if(m<0){
                        //return Math.abs(m) + "分钟后";
                    }else{
                        return "刚刚";
                    }
                }
                
            }else if(d>0){
                if(d == 1){
                    //return "昨天"+getStringByFormat(strDate,outFormat);
                }else if(d==2){
                    //return "前天"+getStringByFormat(strDate,outFormat);
                }
            }else if(d<0){
                if(d == -1){
                    //return "明天"+getStringByFormat(strDate,outFormat);
                }else if(d== -2){
                    //return "后天"+getStringByFormat(strDate,outFormat);
                }else{
                    //return Math.abs(d) + "天后"+getStringByFormat(strDate,outFormat);
                }
            }
            
            String out = getStringByFormat(strDate,outFormat);
            if(!AbStrUtil.isEmpty(out)){
                return out;
            }
        } catch (Exception e) {
        }
        
        return strDate;
    }
    
    
    /**
     * 取指定日期为星期几.
     *
     * @param strDate 指定日期
     * @param inFormat 指定日期格式
     * @return String   星期几
     */
    public static String getWeekNumber(String strDate,String inFormat) {
      String week = "星期日";
      Calendar calendar = new GregorianCalendar();
      DateFormat df = new SimpleDateFormat(inFormat);
      try {
           calendar.setTime(df.parse(strDate));
      } catch (Exception e) {
          return "错误";
      }
      int intTemp = calendar.get(Calendar.DAY_OF_WEEK) - 1;
      switch (intTemp){
        case 0:
          week = "星期日";
          break;
        case 1:
          week = "星期一";
          break;
        case 2:
          week = "星期二";
          break;
        case 3:
          week = "星期三";
          break;
        case 4:
          week = "星期四";
          break;
        case 5:
          week = "星期五";
          break;
        case 6:
          week = "星期六";
          break;
      }
      return week;
    }
    
    /**
     * 根据给定的日期判断是否为上下午.
     *
     * @param strDate the str date
     * @param format the format
     * @return the time quantum
     */
    public static String getTimeQuantum(String strDate, String format) {
        Date mDate = getDateByFormat(strDate, format);
        int hour  = mDate.getHours();
        if(hour >=12)
           return "PM";
        else
           return "AM";
    }
    
    /**
     * 根据给定的毫秒数算得时间的描述.
     *
     * @param milliseconds the milliseconds
     * @return the time description
     */
    public static String getTimeDescription(long milliseconds) {
        if(milliseconds > 1000){
            //大于一分
            if(milliseconds/1000/60>1){
                long minute = milliseconds/1000/60;
                long second = milliseconds/1000%60;
                return minute+"分"+second+"秒";
            }else{
                //显示秒
                return milliseconds/1000+"秒";
            }
        }else{
            return milliseconds+"毫秒";
        }
    }
    
    /**
     * The main method.
     *
     * @param args the arguments
     */
    public static void main(String[] args) {
        System.out.println(formatDateStr2Desc("2012-3-2 12:2:20","MM月dd日  HH:mm"));
    }

}

author 还如一梦中