May 12, 2022 - 3 ' read

How to create a SimpleDateFormat

SimpleDateFormat #

Table content for reference:

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	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

##Some code extensions kotlin:

I use JodaTime library for support handle features

fun String?.formatHour(toPattern: String) = formatHour("HH:mm:ss", toPattern)

fun String?.formatHour(fromPattern: String, toPattern: String): String {
    if (this == null) return ""
    return try {
        DateTime.parse(this, DateTimeFormat.forPattern(fromPattern)).toString(toPattern)
    } catch (e: Exception) {
        "Invalid Date"
    }
}

fun String?.formatDate(toPattern: String): String {
    if (this == null) return ""
    return try {
        DateTime(this).toString(toPattern)
    } catch (e: Exception) {
        "Invalid Date"
    }
}

fun String?.formatDate(fromPattern: String, toPattern: String): String {
    if (this == null) return ""
    return try {
        DateTime.parse(this, DateTimeFormat.forPattern(fromPattern)).toString(toPattern)
    } catch (e: Exception) {
        "Invalid Date"
    }
}

fun String?.parseDate(pattern: String? = null): DateTime? {
    if (this == null) return null
    return try {
        pattern?.let { DateTime.parse(this, DateTimeFormat.forPattern(pattern)) } ?: DateTime(this)
    } catch (e: Exception) {
        null
    }
}