根据用户输入的年月日 判断该日期是星期几 1900/1/1是星期一

方法一：

Scanner input = new Scanner(System.in);
Calendar cal=Calendar.getInstance();
        System.out.println("请输入年:");
        int year=input.nextInt();
        System.out.println("请输入月:");
        int month=input.nextInt();
        System.out.println("请输入日:");
        int day=input.nextInt();

        cal.set(Calendar.YEAR,year);
        cal.set(Calendar.MONTH,month-1);
        cal.set(Calendar.DAY_OF_MONTH,day);

        int dayOfWeek =cal.get(Calendar.DAY_OF_WEEK);

        String d="";
        switch(dayOfWeek){
            case 1:
                d="日";
                break;
            case 2:
                d="一";
                break;
            case 3:
                d="二";
                break;
            case 4:
                d="三";
                break;
            case 5:
                d="四";
                break;
            case 6:
                d="五";
                break;
            case 7:
                d="六";
                break;
        }

        System.out.println(year+"年"+month+"月"+day+"日为星期"+d);

请输入年:
1900
请输入月:
1
请输入日:
1
1900年1月1日为星期一

 

方法二：

public static String dayForWeek(String pTime) throws Throwable {
        SimpleDateFormat format = new SimpleDateFormat("yyyyMMdd");
        Date tmpDate = format.parse(pTime);
        Calendar cal = Calendar.getInstance();
        String[] weekDays = {"7", "1", "2", "3", "4", "5", "6"};
        try {
            cal.setTime(tmpDate);
        } catch (Exception e) {
            e.printStackTrace();
        }
        int w = cal.get(Calendar.DAY_OF_WEEK) - 1; // 指示一个星期中的某天。
        if (w < 0)
            w = 0;
        return weekDays[w];
    }