程序代码：

public class webDate {
   
    public static void main(String[] args)
    {
        date("2013.3.28");
    }
   
    public static void date(String date)
    {
        //天数
        int tmpSumDay = 0 ;
        //星期
        String weekS = "";
        String[] findDate = date.split("\\.");
        int[] userDate = new int[3];
        //转换string->int
        for(int i = 0 ; i < findDate.length ; ++i)
        {
            userDate[i] = Integer.parseInt(findDate[i]);
        }
        //计算年
        for(int year = 1900 ; year < userDate[0] ; ++year)
        {
            if(year % 4 == 0 && year % 100 != 0 || year % 400 ==0)
            {
                tmpSumDay += 366;
            }
            else
            {
                tmpSumDay += 365;
            }
        }
        //计算月
        for(int tMonth = 1 ; tMonth < userDate[1] ; ++ tMonth)
        {
            if(tMonth == 2)
            {
                if(userDate[0] % 4 == 0 && userDate[0] % 100 != 0 || userDate[0] % 400 == 0)
                {
                    tmpSumDay+= 29;
                }
                else
                {
                    tmpSumDay+= 28;
                }
            }
            else if(tMonth == 4 || tMonth == 6 ||tMonth == 9 ||tMonth == 11)
            {
                tmpSumDay+= 30;
            }
            else
            {
                tmpSumDay+= 31;
            }
        }
        //计算天
        tmpSumDay += userDate[2];
        //判断
        int week = tmpSumDay % 7;
        switch(week)
        {
            case 1:
                weekS = "星期一";
                break;
            case 2:
                weekS = "星期二";
                break;
            case 3:
                weekS = "星期三";
                break;
            case 4:
                weekS = "星期四";
                break;
            case 5:
                weekS = "星期五";
                break;
            case 6:
                weekS = "星期六";
                break;
            case 7:
                weekS = "星期日";
                break;           
        }
        System.out.println(weekS);
    }
}