时间工具

原文地址：http://www.oschina.net/code/snippet_132569_8437

import java.util.Calendar;
 
import java.util.Date;
import java.text.SimpleDateFormat;
import java.text.ParsePosition;
import java.util.GregorianCalendar;
 
public class DateTimeUtil {
 
    /**
     * 判断是否润年
     * 
     * @param ddate
     * @return
     */
    public static boolean isLeapYear(String ddate) {
 
        /**
         * 详细设计： 1.被400整除是闰年，否则： 2.不能被4整除则不是闰年 3.能被4整除同时不能被100整除则是闰年
         * 3.能被4整除同时能被100整除则不是闰年
         */
        Date d = strToDate(ddate);
        GregorianCalendar gc = (GregorianCalendar) Calendar.getInstance();
        gc.setTime(d);
        int year = gc.get(Calendar.YEAR);
        if ((year % 400) == 0)
            return true;
        else if ((year % 4) == 0) {
            if ((year % 100) == 0)
                return false;
            else
                return true;
        } else
            return false;
    }
 
    /**
     * 得到一个时间延后或前移几天的时间,nowdate为时间,delay为前移或后延的天数
     */
    public static String getNextDay(String nowdate, String delay) {
        try {
            SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
            String mdate = "";
            Date d = strToDate(nowdate);
            long myTime = (d.getTime() / 1000) + Integer.parseInt(delay) * 24
                    * 60 * 60;
            d.setTime(myTime * 1000);
            mdate = format.format(d);
            return mdate;
        } catch (Exception e) {
            return "";
        }
    }
 
    /**
     * 将短时间格式字符串转换为时间 yyyy-MM-dd
     * 
     * @param strDate
     * @return
     */
    public static Date strToDate(String strDate) {
        SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
        ParsePosition pos = new ParsePosition(0);
        Date strtodate = formatter.parse(strDate, pos);
        return strtodate;
    }
 
     
    public static String strToDate() {
        Date currentTime = new Date();
        SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String dateString = formatter.format(currentTime);
        return dateString;
    }
     
     
    /**
     * 获取一个月的最后一天
     * 
     * @param dat
     * @return
     */
    public static String getEndDateOfMonth(String dat) {// yyyy-MM-dd
        String str = dat.substring(0, 8);
        String month = dat.substring(5, 7);
        int mon = Integer.parseInt(month);
        if (mon == 1 || mon == 3 || mon == 5 || mon == 7 || mon == 8
                || mon == 10 || mon == 12) {
            str += "31";
        } else if (mon == 4 || mon == 6 || mon == 9 || mon == 11) {
            str += "30";
        } else {
            if (isLeapYear(dat)) {
                str += "29";
            } else {
                str += "28";
            }
        }
        return str;
    }
 
    /**
     * 根据一个日期，返回是星期几的字符串
     * 
     * @param sdate
     * @return
     */
    public static String getWeek(String sdate) {
        // 再转换为时间
        Date date = strToDate(sdate);
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        // int hour=c.get(Calendar.DAY_OF_WEEK);
        // hour中存的就是星期几了，其范围 1~7
        // 1=星期日 7=星期六，其他类推
        return new SimpleDateFormat("EEEE").format(c.getTime());
    }
 
    public static String getWeekStr(String sdate) {
        String str = "";
        str = getWeek(sdate);
        if ("1".equals(str)) {
            str = "星期日";
        } else if ("2".equals(str)) {
            str = "星期一";
        } else if ("3".equals(str)) {
            str = "星期二";
        } else if ("4".equals(str)) {
            str = "星期三";
        } else if ("5".equals(str)) {
            str = "星期四";
        } else if ("6".equals(str)) {
            str = "星期五";
        } else if ("7".equals(str)) {
            str = "星期六";
        }
        return str;
    }
 
    public static String getNowMonth(String sdate) {
        // 取该时间所在月的一号
        // sdate = sdate.substring(0, 8) + "01";
        sdate = sdate + "-01";
        // 得到这个月的1号是星期几
        Calendar c = Calendar.getInstance();
        Date date = strToDate(sdate);
        c.setTime(date);
        int u = c.get(Calendar.DAY_OF_WEEK);
        String newday = getNextDay(sdate, (1 - u) + "");
        return newday;
    }
 
    public static String getMonthDate(String sdate) {
        // 取该时间所在月的一号
        // sdate = sdate.substring(0, 8) + "01";
        sdate = sdate + "-01";
        // 得到这个月的1号是星期几
        Calendar c = Calendar.getInstance();
        Date date = strToDate(sdate);
        c.setTime(date);
        int u = c.get(Calendar.DAY_OF_WEEK);
        // for(int i=0;i<)
        String edate = getEndDateOfMonth(sdate);
        String newday;
        newday = getNextDay(sdate, (1 - u) + "");
        String week;
        int i = 0, j = 1;
        System.out.println();
        do {
            newday = getNextDay(sdate, "" + i++);
            week = getWeek(newday);
            if (!week.equals("星期日") && !week.equals("星期六")) {
                System.out.println("第" + (j) + "周");
                System.out.print(newday);
                System.out.print(week);
                System.out.println();
            }
            if (week.equals("星期六"))
                j++;
        } while (!newday.equals(edate));
        return newday;
    }
 
    /**
     * 求某年下的第几个星期的日期 返回java.uilt.Date 类型日期 时间time为当前机器时间
     * 
     * @param year
     *            要获得的年
     * @param week
     *            第几个星期
     * @param flag
     *            是否是第一天还是最后一天,当为true时返回第一天,false则返回最后一天
     * @return java.uilt.Date 类型日期
     * @例如 getDayByWeek(2002,2,true) 返回Tue Jan 08 14:11:57 CST 2002
     */
    public static Date getDayByWeek(int year, int week, boolean flag) {
        Calendar cal = Calendar.getInstance();
        cal.set(Calendar.YEAR, year);
        cal.set(Calendar.WEEK_OF_YEAR, week);
        if (!flag)
            cal.setTimeInMillis(cal.getTimeInMillis() + 6 * 24 * 60 * 60 * 1000);
        return cal.getTime();
    }
 
    /**
     * 取得当前日期是多少周
     * 
     * @param date
     * @return
     */
    public static int getWeekOfYear(Date date) {
        Calendar c = new GregorianCalendar();
        c.setFirstDayOfWeek(Calendar.MONDAY);
        c.setMinimalDaysInFirstWeek(7);
        c.setTime(date);
 
        return c.get(Calendar.WEEK_OF_YEAR);
    }
 
    /**
     * 得到某一年周的总数
     * 
     * @param year
     * @return
     */
    public static int getMaxWeekNumOfYear(int year) {
        Calendar c = new GregorianCalendar();
        c.set(year, Calendar.DECEMBER, 31, 23, 59, 59);
 
        return getWeekOfYear(c.getTime());
    }
 
    /**
     * 得到某年某周的第一天
     * 
     * @param year
     * @param week
     * @return
     */
    public static Date getFirstDayOfWeek(int year, int week) {
        Calendar c = new GregorianCalendar();
        c.set(Calendar.YEAR, year);
        c.set(Calendar.MONTH, Calendar.JANUARY);
        c.set(Calendar.DATE, 1);
 
        Calendar cal = (GregorianCalendar) c.clone();
        cal.add(Calendar.DATE, week * 7);
 
        return getFirstDayOfWeek(cal.getTime());
    }
 
    /**
     * 得到某年某周的最后一天
     * 
     * @param year
     * @param week
     * @return
     */
    public static Date getLastDayOfWeek(int year, int week) {
        Calendar c = new GregorianCalendar();
        c.set(Calendar.YEAR, year);
        c.set(Calendar.MONTH, Calendar.JANUARY);
        c.set(Calendar.DATE, 1);
 
        Calendar cal = (GregorianCalendar) c.clone();
        cal.add(Calendar.DATE, week * 7);
 
        return getLastDayOfWeek(cal.getTime());
    }
 
    /**
     * 取得当前日期所在周的第一天
     * 
     * @param date
     * @return
     */
    public static Date getFirstDayOfWeek(Date date) {
        Calendar c = new GregorianCalendar();
        c.setFirstDayOfWeek(Calendar.MONDAY);
        c.setTime(date);
        c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek()); // Monday
        return c.getTime();
    }
 
    /**
     * 取得当前日期所在周的最后一天
     * 
     * @param date
     * @return
     */
    public static Date getLastDayOfWeek(Date date) {
        Calendar c = new GregorianCalendar();
        c.setFirstDayOfWeek(Calendar.MONDAY);
        c.setTime(date);
        c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek() + 6); // Sunday
        return c.getTime();
    }
 
    public static void main(String[] args) {
        // getMonthDate("2011-05");
 
        int year = 2006;
        int week = 1;
 
        // 以2006-01-02位例
        Calendar c = new GregorianCalendar();
        c.set(2006, Calendar.JANUARY, 2);
        Date d = c.getTime();
 
        System.out.println("current date = " + d);
        System.out.println("getWeekOfYear = " + getWeekOfYear(d));
        System.out
                .println("getMaxWeekNumOfYear = " + getMaxWeekNumOfYear(year));
        System.out.println("getFirstDayOfWeek = "
                + getFirstDayOfWeek(year, week));
        System.out
                .println("getLastDayOfWeek = " + getLastDayOfWeek(year, week));
        System.out.println("getFirstDayOfWeek = " + getFirstDayOfWeek(d));
        System.out.println("getLastDayOfWeek = " + getLastDayOfWeek(d));
    }
 
}