java学习--java.util包中常用类

 1 package com.work.calendar;
 2 
 3 import java.util.Calendar;
 4 import java.util.Scanner;
 5 
 6 
 7 public class CalendarDemo {
 8     int year,month,day=0;
 9     //定义一个存放日期天数的数组
10     int[] days = {31,28,31,30,31,30,31,31,30,31,30,31};
11     Calendar cad ;
12     /**
13      * 无参构造方法中获取当前日期
14      */
15     public CalendarDemo(){
16         cad= Calendar.getInstance();
17         this.year = cad.get(Calendar.YEAR);
18         this.month=cad.get(Calendar.MONTH)+1;
19     }
20     /**
21      * 给日历对象传入一个具体的日期
22      * @param year
23      * @param month
24      * 2018年8月26日
25      */
26     public void setCalendarDemo(int year,int month){
27         this.year = year;
28         this.month = month;
29         cad = Calendar.getInstance();
30         cad.set(Calendar.YEAR, year);
31         cad.set(Calendar.MONTH,month-1);
32     }
33     /**
34      * 将获取到的日历打印
35      * 
36      * 2018年8月26日
37      */
38     public void link() {
39         if(year/4==0&&year/100!=0||year%400 ==0) {
40             days[1]=29;
41         }else {
42             days[1]=28;
43         }
44         System.out.println(year+"年"+month+"月");
45         System.out.println("日\t 一\t 二\t 三\t 四\t 五\t 六");
46         cad.set(Calendar.DAY_OF_MONTH, 1);
47         int first = cad.get(Calendar.DAY_OF_WEEK);
48         for(int i = 0;i) {
49             System.out.print("\t");
50         }
51         for(int i=0;i) {
52             System.out.print(i+1+"\t");
53             if(first==7) {
54                 first=0;
55                 System.out.println();
56             }
57             first++;
58         }
59     }
60     public static void main(String[] args) {
61         int month,year;
62         boolean flag = true;
63         Scanner sc = new Scanner(System.in);
64         System.out.println("请输入年份和月份");
65         year = sc.nextInt();
66         month = sc.nextInt();
67         CalendarDemo c = new CalendarDemo();
68         c.setCalendarDemo(year, month);
69         c.link();
70         while(flag) {
71             System.out.println();
72             System.out.println("输入a，d可以查看上个月，下个月的日历");
73             System.out.println("输入r可以退出程序");
74             char operation = sc.next().charAt(0);
75             if(operation==‘a‘) {
76                 if(month==1) {
77                     year = year - 1;
78                     month = 12;
79                 }else {
80                 month=month-1;
81                 }
82             }else if(operation ==‘d‘){
83                 if(month==12) {
84                     year = year+1;
85                     month = 1;
86                 }else {
87                 month=month+1;
88                 }
89             }else if(operation ==‘r‘) {
90                 flag = false;
91             }
92             c.setCalendarDemo(year, month);
93             c.link();
94             System.out.println();
95             System.out.println("程序已退出");
96         }
97         sc.close();
98     }
99 }