java »ñȡʱ¼äÀà

 public String getCheckDateString(String str) {
        Date date = new Date();//»ñÈ¡µ±Ç°ÏµÍ³ÈÕÆÚ
        SimpleDateFormat format = new SimpleDateFormat("yyyyMMdd");//ʱ¼ä¸ñʽ
        Calendar cal = Calendar.getInstance();
        String CheDate = "";
        if (str.equals("½ñÌì")) {
            date.setTime(date.getTime());
            CheDate = " and s.StudyDate='" + format.format(date) + "'"; // dateFormat.format(toda) µÃµ½µÄÊǽñÌìµÄÈÕÆÚµÄStringÐÎʽ
        } else if (str.equals("×òÌì")) {
            date.setTime(date.getTime() - 24 * 60 * 60 * 1000);
            CheDate = " and s.StudyDate='" + format.format(date) + "'";
        } else if (str.equals("±¾ÖÜ")) {
            cal.setFirstDayOfWeek(Calendar.MONDAY);
            cal.setTime(date);
            int weekno = cal.get(Calendar.WEEK_OF_YEAR);
            cal.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
            cal.set(Calendar.WEEK_OF_YEAR, weekno);
            String from = format.format(cal.getTime());
            cal.setTimeInMillis(cal.getTimeInMillis()