import java.text.ParseException;

 import java.text.SimpleDateFormat;

 import java.util.Calendar;

 import java.util.Date;

 public class date {

     /**

      * @param args

      * @throws ParseException

      */

     public static void main(String[] args) throws ParseException {

         // TODO Auto-generated method stub

         SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

         Date d1=sdf.parse("2012-09-08 10:10:10");

         Date d2=sdf.parse("2012-09-15 00:00:00");

         System.out.println(daysBetween(d1,d2));

         System.out.println(daysBetween("2012-09-08 10:10:10","2012-09-15 00:00:00"));

     }

     /**

      * 计算两个日期之间相差的天数

      * @param smdate 较小的时间

      * @param bdate  较大的时间

      * @return 相差天数

      * @throws ParseException

      */

     public static int daysBetween(Date smdate,Date bdate) throws ParseException

     {

         SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");

         smdate=sdf.parse(sdf.format(smdate));

         bdate=sdf.parse(sdf.format(bdate));

         Calendar cal = Calendar.getInstance();

         cal.setTime(smdate);

         long time1 = cal.getTimeInMillis();

         cal.setTime(bdate);

         long time2 = cal.getTimeInMillis();

         long between_days=(time2-time1)/(1000*3600*24);

        return Integer.parseInt(String.valueOf(between_days));

     }  

 /**

 *字符串的日期格式的计算

 */

     public static int daysBetween(String smdate,String bdate) throws ParseException{

         SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");

         Calendar cal = Calendar.getInstance();

         cal.setTime(sdf.parse(smdate));

         long time1 = cal.getTimeInMillis();

         cal.setTime(sdf.parse(bdate));

         long time2 = cal.getTimeInMillis();

         long between_days=(time2-time1)/(1000*3600*24);

        return Integer.parseInt(String.valueOf(between_days));

     }

 }