Time operations for the Java Calendar class

time operations for the Java Calendar classtags: Javacalendar Time Date2013-07-30 17:53 140401 People read comments (7) favorite reports Classification:all (165) Java algorithm (in)

Copyright Notice: This article for Bo Master original article, without Bo Master permission not Reproduced.

Java Calendar class Time operations, which is perhaps the simplest to create a calendar and management, the demonstration code is SIMPLE.

Demonstrates the acquisition time, the accumulation and subtraction of date time, and the Comparison.

Original Address: blog.csdn.net/joyous/article/details/9630893

Calendar month starts at 0, which means 12 months a year from 0 to 11.

Calendar.sunday = 1
Calendar.monday = 2
Calendar.tuesday = 3
Calendar.wednesday = 4
Calendar.thursday = 5
Calendar.friday = 6
Calendar.saturday = 7

Format definition for SimpleDateFormat

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's 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

The Java Calendar demo code looks like This:

[java]View Plain copy

2. Package demo;
6. Import java.util.Date;
8. Import java.text.SimpleDateFormat;
10. Import java.text.DateFormat;
12. Import java.text.ParseException;
14. Import java.util.Calendar;
18. Public class Test
20. {
22. public Test ()
24. {
26. }
30. public static void main (string[] Args)
32. {
34. //string Conversion Date format
36. //dateformat fmtdatetime = new SimpleDateFormat ("yyyy-mm-dd HH:mm:ss");
38. //receive Incoming Parameters
40. //String strdate = args[1];
42. //get date Format Object
44. //date date = Fmtdatetime.parse (strdate);
48. //full Display of Today's date and time
50. String str = (new SimpleDateFormat ("yyyy-mm-dd HH:mm:ss:SSS")). format (new Date ());
52. System.out.println (str);
56. //create Calendar Object
58. Calendar Calendar = Calendar.getinstance ();
62. Try
64. {
66. //how to set the time for calendar
68. //set the incoming time format
70. SimpleDateFormat DateFormat = new SimpleDateFormat ("yyyy-m-d h:m:s");
72. //specify a Date
74. Date date = Dateformat.parse ("2013-6-1 13:24:16");
76. Date set to date for calendar
78. Calendar.settime (date);
82. //display the time just set in a specific format
84. str = (new SimpleDateFormat ("yyyy-mm-dd HH:mm:ss:SSS")). format (calendar.gettime ());
86. System.out.println (str);
88. }
90. Catch (parseexception e)
92. {
94. E.printstacktrace ();
96. }
100. //or Another setup calendar way
102. //divided for year, month, date, hourofday, minute, Second
104. Calendar = Calendar.getinstance ();
106. Calendar.set (1, 2, n, 44);
108. str = (new SimpleDateFormat ("yyyy-mm-dd HH:mm:ss:SSS")). format (calendar.gettime ());
110. System.out.println (str);
114. //Calendar How to get the current time
116. //initialize (reset) Calendar Object
118. Calendar = Calendar.getinstance ();
120. //or Initialize Calendar object with Date
122. Calendar.settime (new Date ());
126. //settime similar to the above line
128. //date date = new Date ();
130. //calendar.settime (date);
134. str = (new SimpleDateFormat ("yyyy-mm-dd HH:mm:ss:SSS")). format (calendar.gettime ());
136. System.out.println (str);
140. //display Year
142. int year = Calendar.get (calendar.year);
144. System.out.println ("year was =" + string.valueof (year));
148. //display month (starting from 0, actual display to add One)
150. int month = Calendar.get (calendar.month);
152. System.out.println ("nth is =" + (month + 1));
156. //week
158. int week = Calendar.get (calendar.day_of_week);
160. System.out.println ("week is =" + week);
164. //nth Day of the year
166. int day_of_year = Calendar.get (calendar.day_of_year);
168. System.out.println ("day_of_year is =" + day_of_year);
172. //N days of the Month
174. int day_of_month = Calendar.get (calendar.day_of_month);
176. System.out.println ("day_of_month =" + string.valueof (day_of_month));
180. //3 hours later
182. Calendar.add (calendar.hour_of_day, 3);
184. int hour_of_day = Calendar.get (calendar.hour_of_day);
186. System.out.println ("hour_of_day + 3 =" + hour_of_day);
190. //current number of minutes
192. int MINUTE = Calendar.get (calendar.minute);
194. System.out.println ("MINUTE =" + MINUTE);
198. //15 minutes later
200. Calendar.add (calendar.minute, 15);
202. MINUTE = Calendar.get (calendar.minute);
204. System.out.println ("MINUTE + =" + MINUTE);
208. //30 minutes ago
210. Calendar.add (calendar.minute,-30);
212. MINUTE = Calendar.get (calendar.minute);
214. System.out.println ("MINUTE-30 =" + MINUTE);
218. //formatted Display
220. str = (new SimpleDateFormat ("yyyy-mm-dd HH:mm:ss:SS")). format (calendar.gettime ());
222. System.out.println (str);
226. //reset Calendar Show Current Time
228. Calendar.settime (new Date ());
230. str = (new SimpleDateFormat ("yyyy-mm-dd HH:mm:ss:SS")). format (calendar.gettime ());
232. System.out.println (str);
236. //create a Calendar to compare time
238. Calendar calendarnew = calendar.getinstance ();
242. //set to 5 hours ago, latter large, display-1
244. Calendarnew.add (calendar.hour,-5);
246. System.out.println ("time comparison:" + calendarnew.compareto (calendar));
250. //set 7 hours later, The former large, showing 1
252. Calendarnew.add (calendar.hour, +7);
254. System.out.println ("time comparison:" + calendarnew.compareto (calendar));
258. //return 2 hours, same time, display 0
260. Calendarnew.add (calendar.hour,-2);
262. System.out.println ("time comparison:" + calendarnew.compareto (calendar));
264. }
266. }

To calculate the time difference, you can use Calendar.gettimeinmillis () to obtain a microsecond of two times, and then convert it, for example, to obtain the difference in days, the code is as Follows:

[java]View Plain copy

1. A microsecond time Difference.
2. Long val = Calendarend.gettimeinmillis ()-calendarbegin.gettimeinmillis ();
3. Get the number of days after conversion
   

Time operations for the Java Calendar class