Formatting time in Java

Simpledateformat class to solve our time format problem.

Simpledateformat is a type used to format and analyze dates in a language environment-related manner. It allows formatting (date-> text), analysis (text-> date), and normalization. Simpledateformat allows you to select any custom date-Time Format mode.

Date and Time Modes

The date and time formats are specified by the date and time mode strings. Letters that are not enclosed in quotation marks in the date and time format strings'A'To'Z'And'A'To'Z'It is interpreted as a pattern letter used to represent a date or time string element. Single quotes ('."''"Single quotes. All other characters are not interpreted. They are simply copied to the output string during formatting or matched with the input string during analysis.

The following pattern letters are defined (all other characters'A'To'Z'And'A'To'Z'Are retained ):

Letter	Date or time element	Indicates	Example
G	Era identifier	Text	Ad
Y	Year	Year	1996;96
M	Month in Year	Month	July;Jul;07
W	Week in Year	Number	27
W	The number of weeks in the month	Number	2
D	Days in years	Number	189
D	Days in a month	Number	10
F	Week in the month	Number	2
E	Days in a week	Text	Tuesday;Tue
A	AM/PM mark	Text	PM
H	Hours in a day (0-23)	Number	0
K	Hours per day (1-24)	Number	24
K	Hours in AM/PM (0-11)	Number	0
H	Hours in AM/PM (1-12)	Number	12
M	Minutes in an hour	Number	30
S	Seconds in minutes	Number	55
S	Milliseconds	Number	978
Z	Time Zone	General Time Zone	Pacific Standard Time;Pst;GMT-08: 00
Z	Time Zone	RFC 822 Time Zone	-0800

The following example shows how to explain the date and time modes in the U.S. language environment. The given date and time are the local time of the US Pacific Time Zone 12:08:56

 

 

Date and Time Modes	Result
"YYYY. Mm. dd g'at' hh: mm: ss z"	2001.07.04 ad at 12:08:56 PDT
"Eee, mmm D, ''yy"	Wed, Jul 4, '01
"H: mm"	12: 08 pm
"HH 'o' clock 'a, ZZZZ"	12 o 'clock pm, Pacific Daylight Time
"K: Mm A, Z"	0: 08 pm, PDT
"Yyyyy. Mmmmm. dd ggg hh: Mm AAA"	02001. july.04 ad pm
"Eee, d Mmm yyyy hh: mm: ss z"	Wed, 4 Jul 2001 12:08:56-0700
"Yymmddhhmmssz"	010704120856-0700
"Yyyy-mm-dd't'hh: mm: Ss. sssz"	T12: 08: 56.235-0700

 

 

 

 

 

 

 

 

Examples of practical applications of simpledateformat in programming:

(1) format (date-> text)

Generally, the commonly used date and time in Chinese is as follows: 20070719 20:29:30
Simpledateformat formater = new simpledateformat ("yyyymmdd hh: mm: SS ");
System. Out. println ("date to string" + formater. Format (new date ()));

Similar common formats include yymmdd hh: mm: SS yyyy-mm-dd hh: mm: ss dd-mm-yyyy hh: mm: SS
However, it is worth noting that this format (19jul07) and Its similar forms have some tips: 19jul07
Simpledateformat formater = new simpledateformat ("ddmmmyy", new locale ("us "))
System. Out. println ("date to string" + formater. Format (new date (). touppercase ());
Because it is in English, you should use the locale object parameter. Otherwise, the default local locale is used.

(2) analysis (text> date)

Generally, the date and time format and text parameters are used for the desired time format. For example,-7-19, a Java is returned. util. the time object of the date type.

Formater =   New Simpledateformat ( " Yyyymmmdd " , New Locale ( " Us " ));
Try   ... {
System. Out. println ("String to date"+Formater. parse ("2007sep01"));
}   Catch (Parseexception E) ... {
E. printstacktrace ();
}

In particular,

 

Formater =   New Simpledateformat ( " Yyyymmmdd " , New Locale ( " Us " ));
Try   ... {
System. Out. println ("String to date"+Formater. parse ("2007sep01"));
}   Catch (Parseexception E) ... {
E. printstacktrace ();
}

It also returns a date object of the Java. util. date type.

(3) Text-> timestamp, date-> Timestamp

 

Timestamp T;
Simpledateformat format =   New Simpledateformat ( " Yyyy-mm-dd hh: mm: SS " );
Try   ... {
T= NewTimestamp (format. parse ("00:00:00"). Gettime ());
}   Catch (Parseexception E) ... {
E. printstacktrace ();
}

Timestamp T;
Simpledateformat format =   New Simpledateformat ( " Yyyy-mm-dd hh: mm: SS " );
T =   New Timestamp ( New Date (). gettime ());