Instant类的getLong(TemporalField field)方法用于从此瞬间获取作为参数传递的指定字段的long值。此方法在瞬间查询该字段的值，并且返回的值将始终在该字段的值的有效范围内。当不支持该字段并且方法无法返回int值时，将引发异常。
用法:
public int getLong(TemporalField field)
参数：此方法接受一个参数字段，该字段是要获取的字段。它不能为空。
返回值：此方法返回该字段的long值。
异常：此方法引发以下异常：
- DateTimeException：如果无法获取该字段的值，或者该值超出该字段的有效值范围。
- UnsupportedTemporalTypeException：如果不支持该字段或值的范围超过int。
- ArithmeticException：如果发生数字溢出。
以下示例程序旨在说明Instant.getLong()方法：
示例1:
// Java program to demonstrate
// Instant.getLong(TemporalField field) method
import java.time.*;
import java.time.temporal.ChronoField;
public class GFG {
public static void main(String[] args)
{
// create a Instant object
Instant instant
= Instant.parse("2018-12-30T01:34:50.93Z");
// get all enum of chronofield
// and iterate through all enum values
for (ChronoField field : ChronoField.values()) {
try {
// get long value of field
long value = instant.getLong(field);
System.out.println("field : " + field
+ " || value : " + value);
}
catch (Exception e) {
System.out.println("field : " + field
+ " is not supported");
}
}
}
}
输出：
field : NanoOfSecond || value : 930000000 field : NanoOfDay is not supported field : MicroOfSecond || value : 930000 field : MicroOfDay is not supported field : MilliOfSecond || value : 930 field : MilliOfDay is not supported field : SecondOfMinute is not supported field : SecondOfDay is not supported field : MinuteOfHour is not supported field : MinuteOfDay is not supported field : HourOfAmPm is not supported field : ClockHourOfAmPm is not supported field : HourOfDay is not supported field : ClockHourOfDay is not supported field : AmPmOfDay is not supported field : DayOfWeek is not supported field : AlignedDayOfWeekInMonth is not supported field : AlignedDayOfWeekInYear is not supported field : DayOfMonth is not supported field : DayOfYear is not supported field : EpochDay is not supported field : AlignedWeekOfMonth is not supported field : AlignedWeekOfYear is not supported field : MonthOfYear is not supported field : ProlepticMonth is not supported field : YearOfEra is not supported field : Year is not supported field : Era is not supported field : InstantSeconds || value : 1546133690 field : OffsetSeconds is not supported
示例2:
// Java program to demonstrate
// Instant.getLong(TemporalField field) method
import java.time.*;
import java.time.temporal.ChronoField;
public class GFG {
public static void main(String[] args)
{
// create a Instant object
Instant instant
= Instant.parse("2018-12-30T01:34:50.93Z");
// get Instant second value from this Instant
// using getLong method
long secondvalue
= instant.getLong(
ChronoField.INSTANT_SECONDS);
// print result
System.out.println("Instant Seconds: "
+ secondvalue);
}
}
输出：
Instant Seconds: 1546133690
示例3:获取UnsupportedTemporalTypeException
// Java program to demonstrate
// Instant.getLong(TemporalField field) method
import java.time.*;
import java.time.temporal.ChronoField;
public class GFG {
public static void main(String[] args)
{
// create a Instant object
Instant instant
= Instant.parse("2018-12-30T01:34:50.93Z");
// try to find AMPM_OF_DAY
// using ChronoField.AMPM_OF_DAY
// in getLong method
try {
long secondvalue
= instant.getLong(
ChronoField.AMPM_OF_DAY);
}
catch (Exception e) {
// print exception
System.out.println("Exception: " + e);
}
}
}
输出：
Exception: java.time.temporal.UnsupportedTemporalTypeException: Unsupported field: AmPmOfDay
参考：https://docs.oracle.com/javase/10/docs/api/java/time/Instant.html#get(java.time.temporal.TemporalField)
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注：本文由纯净天空筛选整理自AmanSingh2210大神的英文原创作品 Instant getLong() method in Java with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。