/* 
     * 将时间转换为时间戳
     */    
    public static String dateToStamp(String s) throws ParseException{
        String res;
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Date date = simpleDateFormat.parse(s);
        long ts = date.getTime();
        res = String.valueOf(ts);
        return res;
    }

/* 
     * 将时间戳转换为时间
     */
    public static String stampToDate(String s){
        String res;
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        long lt = new Long(s);
        Date date = new Date(lt);
        res = simpleDateFormat.format(date);
        return res;
    }

java.text.SimpleDateFormat formatter =  new  SimpleDateFormat(  "yyyy-MM-dd " );
String s=  "2011-07-09 " ; 搜索
Date date =  formatter.parse(s);