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  
   
    public  static 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=[color=blue][/color]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));
 }