Java 判断时间是否在指定天数之内

import java.util.Date;
import java.text.SimpleDateFormat;


public class WriteForBlog
{
    static private int beforeDays = 8; // Use this vaule to judge the start date within 7 days.
    static private long beforeSeconds = beforeDays * 24 * 60 * 60 * 1000;
    
    public static void main(String[] args)
    {
        String strTime = "2016-10-28";
        if(isNewzt(strTime, beforeSeconds))
        {
            System.out.println("7 days old");
        }
        else
        {
            System.out.println("more than 7 days");
        }
    }
    
    private static boolean isNewzt(String theStrTime, long beforeDays)
    {
        boolean flag = false;
        if("0".equals(theStrTime))
        {
            return flag;
        }

        try
        {
            Date tDat = StrToDate(theStrTime, "");
            long thm = tDat.getTime();
            long chm=System.currentTimeMillis();
            if(thm + beforeDays >=chm)
            {
                flag = true;
            }
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
        return flag;
    }
    
    private static Date StrToDate(String str, String formatStr)
    {
        if (null == formatStr || "".equals(formatStr))
        {
            formatStr = "yyyy-MM-dd";
        }

        SimpleDateFormat format = new SimpleDateFormat(formatStr);
        Date date = null;
        try
        {
            date = format.parse(str);
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
        return date; 
    }

}

    忘记是参考哪个blog的。