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
package TestCalendar; import java.util.Date;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.GregorianCalendar; public class visonCalendar {
public static void main(String args[]){ String temp = "2014-11-11";
Calendar calendar = new GregorianCalendar();
DateFormat df = new SimpleDateFormat("yyyy-MM-dd"); try {
Date date = df.parse(temp);
calendar.setTime(date);
int day = calendar.get(Calendar.DATE);
calendar.set(Calendar.DAY_OF_MONTH, 1);
int FirstDay = calendar.get(Calendar.DAY_OF_WEEK);
int maxDate = calendar.getActualMaximum(Calendar.DATE);
System.out.println(FirstDay); System.out.println("日\t一\t二\t三\t四\t五\t六");
for(int i = 1; i <= maxDate; i++ ){
if (i == day){
System.out.print("*");
}
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"
System.out.print(" \t");
FirstDay--;
} System.out.print(i+"\t");
int w = calendar.get(Calendar.DAY_OF_WEEK);
if(w == Calendar.SATURDAY){ //每到周六换行
System.out.print("\n");
}
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 }
} catch (ParseException e) {
e.printStackTrace();
} } }
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
|