1 /*
  2  *Description:定义工具类
  3  *
  4  * */
  5
  6 package tools;
  7
  8 import java.util.Scanner;
  9
 10 public class Operate {
 11
 12     //定义方法，判断一个年是否是闰年
 13     public static boolean ifLeapyear(int year) {
 14
 15         if( year % 400 == 0 ) {            //能被400整除
 16
 17             return true;
 18         }else if( year % 100 != 0 && year % 4 == 0 ) {        //不是100倍数，但是能被4整除
 19
 20             return true;
 21         }else {
 22
 23             return false;
 24         }
 25     }
 26
 27     //判断某年某月有多少天
 28     public static int getDays(String yearMonth) {
 29
 30         String array[] = yearMonth.split("-");
 31         int year = Integer.parseInt( array[0] );
 32         int month = Integer.parseInt( array[1] );
 33         int monthOne[] = {31,29,31,30,31,30,31,31,30,31,30,31};
 34         int monthTwo[] = {31,28,31,30,31,30,31,31,30,31,30,31};
 35
 36         if( Operate.ifLeapyear(year) ) {
 37             return monthOne[month-1];
 38         }
 39         return monthTwo[month-1];
 40     }
 41
 42     //接收用户的输入
 43     public static String getInput() {
 44
 45         Scanner scan = new Scanner(System.in);
 46         String yearMonth = "";
 47         System.out.println( "请输入年月，中间用'-'分开：" );
 48         yearMonth = scan.next();
 49
 50         return yearMonth;
 51     }
 52
 53     //验证用户输入数据的合法性
 54     public static boolean validate(String yearMonth) {
 55
 56         if( yearMonth.matches( "\\d{4}\\W\\d{1,2}" ) ) {    //进行正则匹配
 57
 58             String str[] = yearMonth.split("-");
 59
 60             if( Integer.parseInt( str[0] ) < 1900 ) {    //年份小于1990
 61                 return true;
 62             }
 63
 64             //月份不在1-12月之间
 65             if( Integer.parseInt(str[1]) < 1 || Integer.parseInt( str[1] ) > 12 ) {
 66
 67                 return true;
 68             }
 69
 70             return false;
 71
 72         }else {
 73             return true;
 74         }
 75     }
 76
 77     //计算某年某月距离1990年有多少天
 78     public static int getAllDays(int year,int month,int[] monthOne,int[] monthTwo) {
 79         int count = 0;
 80         for( int i = 1900;i < year; i++ ) {
 81
 82             if( Operate.ifLeapyear(i) ) {
 83                 count += 366;
 84             }else {
 85
 86                 count += 365;
 87             }
 88         }
 89
 90         for( int i = 0; i < month - 1; i++ ) {
 91
 92             if( Operate.ifLeapyear(year) ) {
 93
 94                 count += monthOne[i];
 95             }else {
 96
 97                 count += monthTwo[i];
 98             }
 99         }
100         return count;
101     }
102
103
104     //打印日历
105     public static void printDate(String yearMonth) {
106         String array[] = yearMonth.split("-");
107         int year = Integer.parseInt( array[0] );
108         int month = Integer.parseInt( array[1] );
109         int monthOne[] = {31,29,31,30,31,30,31,31,30,31,30,31};        //闰年每个月的天数
110         int monthTwo[] = {31,28,31,30,31,30,31,31,30,31,30,31};        //平年每个月的天数
111         int count = 0;
112
113         count = Operate.getAllDays(year, month, monthOne, monthTwo);    //得到天数
114
115         int remainDays = count % 7;            //除以7。看看剩余的天数
116         int monthDays = Operate.getDays(yearMonth);        //得到目标月份的天数
117         String[] days = new String[remainDays + monthDays + 2];        //开辟一个String数组,存放打印的内容
118
119         int k = 1;
120         for(int i = 0; i < days.length; i++) {            //为数组赋值
121
122             if( i < remainDays + 1 ) {
123                 days[i] = " ";
124             }else {
125                 days[i] = k + "";
126                 k++;
127             }
128         }
129
130         //打印出rili
131         System.out.println( "---------------------" + year + "年" + month + "月" +  "---------------------" );
132         System.out.println( "日\t一\t二\t三\t四\t五\t六" );
133         for( int i = 0; i < days.length; i++ ) {
134
135             System.out.print(days[i] + "\t");
136             if( (i + 1) % 7 == 0 ) {            //每七天换行
137                 System.out.println();
138             }
139         }
140     }
141
142 }

 1 /*
 2  * Description:打印某年某月的日历
 3  *
 4  * Written By:Cai
 5  *
 6  * Date Written:2017-09-24
 7  *
 8  * */
 9
10 package main;
11 import tools.Operate;
12
13
14 public class DemoTwo2 {
15
16     public static void main(String args[]) {
17
18         String input = "";        //接收用户输入的值
19         boolean flag = true;
20         while( flag ) {            //判断用户输入的日期是否合法
21             input = Operate.getInput();
22             if( Operate.validate(input) ) {            //调用方法检测
23
24                 System.out.println( "输入日期格式错误，请重新输入：" );
25             }else {
26
27                 flag = false;
28             }
29         }
30
31         Operate.printDate(input);            //打印rili
32     }
33 }