统计时间周,月的计算.

计算周: getDateInWeek()和DateAdd()两个方法

//返回一个日期字符串在星期中的顺序
public static int getDateInWeek(String strDate) {
  DateFormat df = DateFormat.getDateInstance();
  try {
    df.parse(strDate);
    java.util.Calendar c = df.getCalendar();
    int day = c.get(c.DAY_OF_WEEK) - c.SUNDAY;
    return day;
  }
  catch (ParseException e) {
    return -1;
  }
}

//一个日期上加天数
public static String DateAdd(String startDate, int dd) {
  java.text.DateFormat df = java.text.DateFormat.getDateInstance();
  java.util.Date date = new java.util.Date();
  try {
    date = df.parse(startDate);
  }
  catch (Exception ex) {
    System.out.print(ex);
  }

  Calendar calendar = Calendar.getInstance();
  calendar.setTime(date);

  calendar.add(Calendar.DATE, dd);

  String mm = String.valueOf(calendar.get(Calendar.MONTH) + 1);
  if (mm.length() == 1) {
    mm = "0" + mm;
  }
  String day = String.valueOf(calendar.get(Calendar.DATE));
  if (day.length() == 1) {
    day = "0" + day;

  }
  String returnDate = String.valueOf(calendar.get(Calendar.YEAR)) + "-" + mm
      + "-" + day;

  return returnDate;

}

计算月:getCurrentTime("yyyy-MM");返回年-月格式的时间.再将数据库中时间substring(),然后比较.

public static String getCurrentTime(String style) {
   SimpleDateFormat format = new SimpleDateFormat(style);
   return format.format(new Timestamp(System.currentTimeMillis()));
}