Java对时间(周)的处理 方法整理

/**     * 增加天数,减传负值     * @param format     * @param day     * @return     */    public static String getDateBeforeForma(String format, int day){    DateFormat dateFormat = new SimpleDateFormat(format);    Calendar now = Calendar.getInstance();          now.add(Calendar.DATE, day);//增加一天 ,减传负值           Date date=now.getTime();            return dateFormat.format(date);    }    /**     * 获得本周第一天(周一)的日期      * @return     */    public static String getWeekDay()    {    Calendar cal =Calendar.getInstance();        SimpleDateFormat df = new SimpleDateFormat("yyyy/MM/dd");        cal.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY); //获取本周一的日期        String time = df.format(cal.getTime());    return time;    }        /**     * 获得上周时间     * @return     */    public static String getLastWeek() {    SimpleDateFormat df = new SimpleDateFormat("yyyy/MM/dd");    Calendar date = Calendar.getInstance(Locale.CHINA);        date.setFirstDayOfWeek(Calendar.MONDAY);//将每周第一天设为星期一，默认是星期天        date.add(Calendar.WEEK_OF_MONTH,-1);//周数减一，即上周        date.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);//日子设为星期一        String time = df.format(date.getTime());                Calendar date2 = Calendar.getInstance(Locale.CHINA);        date2.setFirstDayOfWeek(Calendar.MONDAY);//将每周第一天设为星期一，默认是星期天        date2.add(Calendar.WEEK_OF_MONTH,-1);//周数减一，即上周        date2.set(Calendar.DAY_OF_WEEK, Calendar.SUNDAY);//日子设为星期天        String time2 = df.format(date2.getTime());                return time + "-" + time2;}        /**      * 获取某一时间段特定星期几的日期      * @param dateFrom 开始时间      * @param dateEnd 结束时间      * @param weekDays 星期      * @return 返回时间数组      */      public static String[] getDates(String dateFrom, String dateEnd, String weekDays) {          long time = 1l;          long perDayMilSec = 24 * 60 * 60 * 1000;          List<String> dateList = new ArrayList<String>();          SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd");          //需要查询的星期系数          String strWeekNumber = weekForNum(weekDays);          try {              dateFrom = sdf.format(sdf.parse(dateFrom).getTime() - perDayMilSec);              while (true) {                      time = sdf.parse(dateFrom).getTime();                      time = time + perDayMilSec;                      Date date = new Date(time);                      dateFrom = sdf.format(date);                      if (dateFrom.compareTo(dateEnd) <= 0) {                          //查询的某一时间的星期系数                          Integer weekDay = dayForWeek(date);                                              //判断当期日期的星期系数是否是需要查询的                          if (strWeekNumber.indexOf(weekDay.toString())!=-1) {                              dateList.add(dateFrom);                          }                      } else {                          break;                      }              }          } catch (ParseException e1) {              e1.printStackTrace();          }          String[] dateArray = new String[dateList.size()];          dateList.toArray(dateArray);          return dateArray;      }        //等到当期时间的周系数。星期日：1，星期一：2，星期二：3，星期三：4，星期四：5，星期五：6，星期六：7      public static Integer dayForWeek(Date date) {          Calendar calendar = Calendar.getInstance();          calendar.setTime(date);          return calendar.get(Calendar.DAY_OF_WEEK);      }            /**      * 得到对应星期的系数  星期日：1，星期一：2，星期二：3，星期三：4，星期四：5，星期五：6，星期六：7      * @param weekDays 星期格式  星期一|星期二      */      public static String weekForNum(String weekDays){          //返回结果为组合的星期系数          String weekNumber = "";          //解析传入的星期          if(weekDays.indexOf("|")!=-1){//多个星期数              String []strWeeks = weekDays.split("\\|");              for(int i=0;i<strWeeks.length;i++){                  weekNumber = weekNumber + "" + getWeekNum(strWeeks[i]).toString();              }          }else{//一个星期数              weekNumber = getWeekNum(weekDays).toString();          }                    return weekNumber;                }            //将星期转换为对应的系数  星期日：1，星期一：2，星期二：3，星期三：4，星期四：5，星期五：6，星期六：7      public static Integer getWeekNum(String strWeek){          Integer number = 1;//默认为星期日          if("星期日".equals(strWeek)){              number = 1;          }else if("星期一".equals(strWeek)){              number = 2;          }else if("星期二".equals(strWeek)){              number = 3;          }else if("星期三".equals(strWeek)){              number = 4;          }else if("星期四".equals(strWeek)){              number = 5;          }else if("星期五".equals(strWeek)){              number = 6;          }else if("星期六".equals(strWeek)){              number = 7;          }else{              number = 1;          }          return number;      }         //根据年份和当年的第几周，获取这一周的日期    public static String getDayOfWeek(int year, int weekindex) {        SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd");        Calendar c = Calendar.getInstance();        c.setWeekDate(year, weekindex, 1);         int dayOfWeek = c.get(Calendar.DAY_OF_WEEK) - 2;        c.add(Calendar.DATE, -dayOfWeek); // 得到本周的第一天        String begin = sdf.format(c.getTime());        c.add(Calendar.DATE, 6); // 得到本周的最后一天        String end = sdf.format(c.getTime());        String range = begin + "-" + end;        return range;    }