写在前面
博文安排顺序如下
1.写在前面
2.源码
3.思路
4.相关知识
该小程序是对Date类及其相关类的复习
要求如下图:实现可视化日历
实现思路
1.先从键盘输入指定格式的字符串(str)
2.将字符串用格式转换类转换成日期( Date date = format.parse(str) )
3.将日期设置成日历类( calendar.setTime(date) )
4.获取当月第一天是周几( calendar.get(Calendar.DAY_OF_WEEK) )
5.获取当月多少天( calendar.getActualMaximum(Calendar.DATE) )
6.按格式输出
源码
1 package TestCalendar; 2 3 import java.util.Date; 4 import java.text.DateFormat; 5 import java.text.ParseException; 6 import java.text.SimpleDateFormat; 7 import java.util.Calendar; 8 import java.util.GregorianCalendar; 9 10 11 public class visonCalendar { 12 public static void main(String args[]){ 13 14 String temp = "2014-11-11"; 15 Calendar calendar = new GregorianCalendar(); 16 DateFormat df = new SimpleDateFormat("yyyy-MM-dd"); 17 18 try { 19 Date date = df.parse(temp); 20 calendar.setTime(date); 21 int day = calendar.get(Calendar.DATE); 22 calendar.set(Calendar.DAY_OF_MONTH, 1); 23 int FirstDay = calendar.get(Calendar.DAY_OF_WEEK); 24 int maxDate = calendar.getActualMaximum(Calendar.DATE); 25 System.out.println(FirstDay); 26 27 System.out.println("日\t一\t二\t三\t四\t五\t六"); 28 for(int i = 1; i <= maxDate; i++ ){ 29 if (i == day){ 30 System.out.print("*"); 31 } 32 while((FirstDay-1)>0){ //按照需要打印的格式,本月1号从第FirstDay天开始,所以前面需要(FirstDay-1)个" \t" 33 System.out.print(" \t"); 34 FirstDay--; 35 } 36 37 System.out.print(i+"\t"); 38 int w = calendar.get(Calendar.DAY_OF_WEEK); 39 if(w == Calendar.SATURDAY){ //每到周六换行 40 System.out.print("\n"); 41 } 42 calendar.add(Calendar.DATE, 1); //从1号开始打印,每次打印完日期加1,否则换行if判断无效 43 44 } 45 } catch (ParseException e) { 46 e.printStackTrace(); 47 } 48 49 } 50 51 }
相关知识
Calendar 的 month 从 0 开始,也就是全年 12 个月由 0 ~ 11 进行表示。
而 Calendar.DAY_OF_WEEK 定义和值如下:
Calendar.SUNDAY = 1
Calendar.MONDAY = 2
Calendar.TUESDAY = 3
Calendar.WEDNESDAY = 4
Calendar.THURSDAY = 5
Calendar.FRIDAY = 6
Calendar.SATURDAY = 7
SimpleDateFormat 的格式定义
Letter | Date or Time Component | Presentation | Examples |
---|---|---|---|
G | Era designator | Text | AD |
y | Year | Year | 1996 ; 96 |
Y | Week year | Year | 2009 ; 09 |
M | Month in year (context sensitive) | Month | July ; Jul ; 07 |
L | Month in year (standalone form) | Month | July ; Jul ; 07 |
w | Week in year | Number | 27 |
W | Week in month | Number | 2 |
D | Day in year | Number | 189 |
d | Day in month | Number | 10 |
F | Day of week in month | Number | 2 |
E | Day name in week | Text | Tuesday ; Tue |
u | Day number of week (1 = Monday, ..., 7 = Sunday) | Number | 1 |
a | Am/pm marker | Text | PM |
H | Hour in day (0-23) | Number | 0 |
k | Hour in day (1-24) | Number | 24 |
K | Hour in am/pm (0-11) | Number | 0 |
h | Hour in am/pm (1-12) | Number | 12 |
m | Minute in hour | Number | 30 |
s | Second in minute | Number | 55 |
S | Millisecond | Number | 978 |
z | Time zone | General time zone | Pacific Standard Time ; PST ; GMT-08:00 |
Z | Time zone | RFC 822 time zone | -0800 |
X | Time zone | ISO 8601 time zone | -08 ; -0800 ; -08:00 |