EN
Java 8 - how to create custom DateTimeFormatter with DateTimeFormatterBuilder?
4 points
Java 8 introduced DateTimeFormatter and DateTimeFormatterBuilder to give programmers more control over date time formats.
DateTimeFormatter has already build-in date time formatters.
We can use DateTimeFormatterBuilder to create our own date time formatter.
Code example:
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import java.time.LocalDateTime;2
import java.time.format.DateTimeFormatter;3
import java.time.format.DateTimeFormatterBuilder;4
import java.time.temporal.ChronoField;5
6
public class DateTimeFormatterBuilderExample1 {7
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public static void main(String[] args) {9
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DateTimeFormatterBuilder builder = new DateTimeFormatterBuilder();11
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DateTimeFormatter formatter = builder13
//14
.appendLiteral("year: ")15
.appendValue(ChronoField.YEAR)16
//17
.appendLiteral(", month: ")18
.appendValue(ChronoField.MONTH_OF_YEAR)19
//20
.appendLiteral(", day: ")21
.appendValue(ChronoField.DAY_OF_MONTH)22
//23
.toFormatter();24
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LocalDateTime localDateTime = LocalDateTime.now();26
String dateTimeNow = localDateTime.format(formatter);27
28
// 2019-10-12T15:21:15.09629
System.out.println(localDateTime);30
31
// year: 2019, month: 10, day: 1232
System.out.println(dateTimeNow);33
}34
}Output:
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2019-10-12T15:21:15.0962
year: 2019, month: 10, day: 12Code example:
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import java.time.LocalDateTime;2
import java.time.format.DateTimeFormatter;3
import java.time.format.DateTimeFormatterBuilder;4
import java.time.temporal.ChronoField;5
6
public class DateTimeFormatterBuilderExample2 {7
8
public static void main(String[] args) {9
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DateTimeFormatterBuilder builder = new DateTimeFormatterBuilder();11
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DateTimeFormatter formatter = builder.13
//14
appendLiteral("year: ")15
.appendValue(ChronoField.YEAR)16
//17
.appendLiteral(", month: ")18
.appendValue(ChronoField.MONTH_OF_YEAR)19
//20
.appendLiteral(", day: ")21
.appendValue(ChronoField.DAY_OF_MONTH)22
//23
.appendLiteral(", hour: ")24
.appendValue(ChronoField.HOUR_OF_DAY)25
//26
.appendLiteral(", minute: ")27
.appendValue(ChronoField.MINUTE_OF_HOUR)28
//29
.appendLiteral(", second: ")30
.appendValue(ChronoField.SECOND_OF_MINUTE)31
//32
.appendLiteral(", milli: ")33
.appendValue(ChronoField.MILLI_OF_SECOND)34
//35
.appendLiteral(", micro: ")36
.appendValue(ChronoField.MICRO_OF_SECOND)37
//38
.toFormatter();39
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LocalDateTime localDateTime = LocalDateTime.now();41
String dateTimeNow = localDateTime.format(formatter);42
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// 2019-10-12T15:21:57.40744
System.out.println(localDateTime);45
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// year: 2019, month: 10, day: 12, 47
// hour: 15, minute: 21, second: 57, milli: 407, micro: 40700048
System.out.println(dateTimeNow);49
}50
}Output:
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2019-10-12T15:21:57.4072
year: 2019, month: 10, day: 12, hour: 15, minute: 21, second: 57, milli: 407, micro: 407000