In the date formatted, I used to describe how to customize the date format text from a java.util.date date class. Today we will enter a real problem, learn about the real date object Calendar class in Java, and build a practical SWING calendar bean during the analysis process.
I have searched some practical SWING calendars online, but their implementation is more complicated. Here we will use only one class and standard Swing components to implement this calendar, so that this bean can be easily reused.
First, what is Calendar?
The Calendar class is a calendar tool class provided by the Java Standard Library, which is an abstract class. Among it defines a number of useful methods, the most useful is to freely transform the date and time of the SET method, and get the GET method output from the custom date. Because Calendar is an abstract class, it can't create an instance using the new method, it needs to be used: Calendar Calendar = Calendar.getInstance ();
In the Calendar class, the date is divided into the year, month, day, time, minute, second, microseconds, west of eight parts, each portion has one or more domains (Field), in the use of SET or GET methods It is actually accessed through these domains. Every domain is a static integer constant, they are:
area
Representative meaning
AM_PM
AM / afternoon logo
Date
Complete date logo
Day_of_month
The first few days this month
Day_of_week
Day of the week
Day_of_week_in_month
(Not understood)
Day_of_year
The first few days of this year
DST_OFFSET
Time zone offset
ERA
BC mark
Hour
Hours (12 hours, division on the afternoon)
Hour_of_day
Hours (24-hour system, regardless of afternoon)
MilliseCond
Microseconds
Minute
minute
Month
month
SECOND
second
WEEK_OF_MONTH
The first week of this month
WEEK_OF_YEAR
The first week of this year
Year
years
ZONE_OFFSET
Microsecondal time offset relative to the GMT time zone
In addition to the functionality of accessing domain values via set and get methods, Calendar provides some useful methods:
method
parameter
significance
getActualMaximum
Int Field
Get the maximum value of the current time specified domain value
getActualMinimumum
Equally
Get the minimum value of the current time specified domain value
GetFirstdayofweek
air
Get the first day of the current time zone for a week,
Such as: Sunday is the first day of a week;
It is Monday in France.
GetTime
air
Return a java.util.date date object
GetTimeInmillis
air
Returns the cumulative value of the current time, just like
GetTime method in java.util.date
GetTimezone
air
Returns the current time zone
Isset
Int Field
Set whether the domain can be rewritten
SetFirstdayofweek
Int Value
Set the first day of the current time zone for a week,
Such as: Sunday is the first day of a week;
It is Monday in France.
Settime
Date Date
Reset a java.util.date for the current calendar
Date object as the current time
SetTimeInmillis
air
Set a microsecond accumulated value for a time as the current time
Settimezone
Timezone Value
Set the current time zone
