获取一年中按星期归类（星期一、星期二...）所有日期

public static Map> getDatesByWeek(){
 
    Calendar c_begin = new GregorianCalendar();
    Calendar c_end = new GregorianCalendar();
    DateFormatSymbols dfs = new DateFormatSymbols();
    String[] weeks = dfs.getWeekdays();
    int year = DateUtil.getYear();
    int month = DateUtil.getMonth();
    int day = DateUtil.getToDayOfMonth();
    c_begin.set(year, month, day); //Calendar的月从0-11，
    c_end.set(year, 11, 31); //Calendar的月从0-11，
    List scheduledDates=new ArrayList();
    Map> map = new HashMap>();
    int count = 1;
    c_end.add(Calendar.DAY_OF_YEAR, 1);  //结束日期下滚一天是为了包含最后一天
    
    while(c_begin.before(c_end)){
//       System.out.println("第"+count+"周  日期："+new java.sql.Date(c_begin.getTime().getTime())+","+weeks[c_begin.get(Calendar.DAY_OF_WEEK)]);
      String DAY_OF_WEEK=weeks[c_begin.get(Calendar.DAY_OF_WEEK)];
      
      Date date = c_begin.getTime();
      if(!map.containsKey(DAY_OF_WEEK)){
      map.put(DAY_OF_WEEK, new ArrayList());
      }
      map.get(DAY_OF_WEEK).add(date);
      
      if(c_begin.get(Calendar.DAY_OF_WEEK)==Calendar.SUNDAY){
      count++;
      }
     c_begin.add(Calendar.DAY_OF_YEAR, 1);
    }
  return map;
}