下面这段代码我的目的是就算某年某月的第一天是星期几，可是不对，我是按照这种方法做的  ：1900年1月1日星期一 作为标杆
然后算当月第一天距1900.1.1多少天，取余7，不知道哪里有问题，求指教啊
package rili;

import java.util.Scanner;

public class rili {
    boolean isRunNian(int year) {
        if ((year % 400 == 0) || (year % 4 == 0 && year % 100 != 0))
            return true;
        else
            return false;
    }

    int calcDayOfMonth(int year, int month) {
        int days = 0;
        int sum = 0;
        for (int i = 1; i <= month; i++) {
            switch (month) {
            case 1:
            case 3:
            case 5:
            case 7:
            case 8:
            case 10:
            case 12:
                days = 31;
                break;
            case 4:
            case 6:
            case 9:
            case 11:
                days = 30;
                break;
            case 2:
                if (isRunNian(year))
                    days = 29;
                else
                    days = 28;

            }
            sum += days;
        }
        return sum;
    }

    int calcDays(int year, int month) {
        int sum = 0;
        int days;
        for (int i = 1900; i < year; i++) {
            if (isRunNian(i)) {
                sum += 366;
            } else {
                sum += 365;
            }
        }
        // 对月份中的天数进行处理
        days = calcDayOfMonth(year, month);
        sum += days;
        return sum;

    }

    public static void main(String[] args) {
        // TODO 自动生成的方法存根
        rili r=new rili();
        Scanner s = new Scanner(System.in);
        int year;
        int month;
        year = s.nextInt();
        month = s.nextInt();
        int sum=r.calcDays(year,month-1);
        System.out.println((sum)%7+1);

    }

}

import java.util.Scanner;

 public class S {
     boolean isRunNian(int year) {
         if ((year % 400 == 0) || (year % 4 == 0 && year % 100 != 0))
             return true;
         else
             return false;
     }

     int calcDayOfMonth(int year, int month) {
         int days = 0;
         int sum = 0;
         for (int i = 1; i <= month; i++) {
             switch (i) {            //这里应该用i做参数
             case 1:
             case 3:
             case 5:
             case 7:
             case 8:
             case 10:
             case 12:
                 days = 31;
                 break;
             case 4:
             case 6:
             case 9:
             case 11:
                 days = 30;
                 break;
             case 2:
                 if (isRunNian(year))
                     days = 29;
                 else
                     days = 28;

             }
             sum += days;
         }
         return sum;
     }

     int calcDays(int year, int month) {
         int sum = 0;
         int days;
         for (int i = 1900; i < year; i++) {
             if (isRunNian(i)) {
                 sum += 366;
             } else {
                 sum += 365;
             }
         }
         // 对月份中的天数进行处理
        days = calcDayOfMonth(year, month);
         sum += days;
         return sum;

     }

     public static void main(String[] args) {
         // TODO 自动生成的方法存根
        S r=new S();
         Scanner s = new Scanner(System.in);
         int year;
         int month;
         year = s.nextInt();
         month = s.nextInt();
         int sum=r.calcDays(year,month-1);
         System.out.println((sum)%7+1);

     }
}

谢谢你啊，比我仔细多了，我太不仔细了，求个联系方式吧，以后多沟通。我QQ1020196987

经过测试。这段代码，是错误的。改正后。无法得到，想要的结果