import java.text.SimpleDateFormat;
import java.util.Date;
public class TimeUtil {

    public TimeUtil() {
        // TODO Auto-generated constructor stub
    }

    public static void main(String[] args){
        long startTime = 1516636799;
        long endTime = 1516636800;
        System.out.println(equation(startTime * 1000
 
, System.currentTimeMillis()));
        System.out.println(System.currentTimeMillis());
    }
    //計算兩個時間戳間隔多少天
    public static int equation(long startTime, long endTime) {
        startTime = dateToStamp(stampToDate(startTime));
        endTime = dateToStamp(stampToDate(endTime));
        int newL = (int
 
) ((endTime - startTime) / (1000 * 3600 * 24));
        return newL;

    }

    /*
     * 將時間戳轉換為時間
     */
    public static String stampToDate(long l) {
        String res;
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");
        long lt = l;
        Date date = new Date(lt);
        res = simpleDateFormat.format(date);
        return
 
 res;
    }

    /*
     * 將時間轉換為時間戳
     */
    public static long dateToStamp(String s) {
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");
        Date date = null;
        try {
            date = simpleDateFormat.parse(s);
            return date.getTime();
        } catch (java.text.ParseException e) {
            // TODO Auto-generated catch block

            e.printStackTrace();
            return -1;
        }

    }
}