java 时间类 工具

package com.test;import java.text.ParsePosition;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;import java.util.GregorianCalendar;public class Days {    /**     * @param args     *      */    private int weeks = 0;    public static void main(String[] args) {        Days tt = new Days();        System.out.println("获取昨天日期:" + tt.getyd());        System.out.println("获取当天日期:" + tt.getNowTime("yyyy-MM-dd"));        System.out.println("获取本周一日期:" + tt.getMondayOFWeek());        System.out.println("获取本周日的日期~:" + tt.getCurrentWeekday());        System.out.println("获取上周一日期:" + tt.getPreviousWeekday());        System.out.println("获取上周日日期:" + tt.getPreviousWeekSunday());        System.out.println("获取本月第一天日期:" + tt.getFirstDayOfMonth());        System.out.println("获取本月最后一天日期:" + tt.getDefaultDay());        System.out.println("获取上月第一天日期:" + tt.getPreviousMonthFirst());        System.out.println("获取上月最后一天的日期:" + tt.getPreviousMonthEnd());    }    public static String getWeek(String sdate)      {        Date date = strToDate(sdate);        Calendar c = Calendar.getInstance();        c.setTime(date);        return new SimpleDateFormat("EEEE").format(c.getTime());      }      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 long getDays(String date1, String date2)      {        if ((date1 == null) || (date1.equals("")))        {          return 0L;        }        if ((date2 == null) || (date2.equals("")))        {          return 0L;        }        SimpleDateFormat myFormatter = new SimpleDateFormat("yyyy-MM-dd");        Date date = null;        Date mydate = null;        try        {          date = myFormatter.parse(date1);          mydate = myFormatter.parse(date2);        }        catch (Exception localException)        {        }        long day = (date.getTime() - mydate.getTime()) / 86400000L;        return day;      }      public String getyd()      {        Calendar cal = Calendar.getInstance();        cal.add(5, -1);        String yesterday = new SimpleDateFormat("yyyy-MM-dd ").format(cal.getTime());        return yesterday;      }      public String getDefaultDay()      {        String str = "";        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");        Calendar lastDate = Calendar.getInstance();        lastDate.set(5, 1);        lastDate.add(2, 1);        lastDate.add(5, -1);        str = sdf.format(lastDate.getTime());        return str;      }      public String getPreviousMonthFirst()      {        String str = "";        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");        Calendar lastDate = Calendar.getInstance();        lastDate.set(5, 1);        lastDate.add(2, -1);        str = sdf.format(lastDate.getTime());        return str;      }      public String getFirstDayOfMonth()      {        String str = "";        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");        Calendar lastDate = Calendar.getInstance();        lastDate.set(5, 1);        str = sdf.format(lastDate.getTime());        return str;      }      public String getCurrentWeekday()      {        this.weeks = 0;        int mondayPlus = getMondayPlus();        GregorianCalendar currentDate = new GregorianCalendar();        currentDate.add(5, mondayPlus + 6);        Date monday = currentDate.getTime();        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");        String preMonday = sdf.format(monday);        return preMonday;      }      public String getNowTime(String dateformat)      {        Date now = new Date();        SimpleDateFormat dateFormat = new SimpleDateFormat(dateformat);        String hehe = dateFormat.format(now);        return hehe;      }      private int getMondayPlus()      {        Calendar cd = Calendar.getInstance();        int dayOfWeek = cd.get(7) - 1;        if (dayOfWeek == 1)        {          return 0;        }        return (1 - dayOfWeek);      }      public String getMondayOFWeek()      {        this.weeks = 0;        int mondayPlus = getMondayPlus();        GregorianCalendar currentDate = new GregorianCalendar();        currentDate.add(5, mondayPlus);        Date monday = currentDate.getTime();        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");        String preMonday = sdf.format(monday);        return preMonday;      }      public String getPreviousWeekSunday()      {        this.weeks = 0;        this.weeks -= 1;        int mondayPlus = getMondayPlus();        GregorianCalendar currentDate = new GregorianCalendar();        currentDate.add(5, mondayPlus + this.weeks);        Date monday = currentDate.getTime();        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");        String preMonday = sdf.format(monday);        return preMonday;      }      public String getPreviousWeekday()      {        this.weeks -= 1;        int mondayPlus = getMondayPlus();        GregorianCalendar currentDate = new GregorianCalendar();        currentDate.add(5, mondayPlus + 7 * this.weeks);        Date monday = currentDate.getTime();        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");        String preMonday = sdf.format(monday);        return preMonday;      }      public String getPreviousMonthEnd()      {        String str = "";        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");        Calendar lastDate = Calendar.getInstance();        lastDate.add(2, -1);        lastDate.set(5, 1);        lastDate.roll(5, -1);        str = sdf.format(lastDate.getTime());        return str;      }}