Java中的即时toString()方法
字段值的范围可以使用range()Java中Instant类中的方法获得。此方法需要一个参数，即ChronoField，需要该参数的值的范围，并且它返回ChronoField的有效值的范围。
演示此的程序如下所示-
示例
import java.time.*;
import java.time.temporal.ChronoField;
import java.time.temporal.ValueRange;
public class Demo {
public static void main(String[] args) {
Instant i = Instant.now();
ValueRange range1 = i.range(ChronoField.MILLI_OF_SECOND);
ValueRange range2 = i.range(ChronoField.MICRO_OF_SECOND);
ValueRange range3 = i.range(ChronoField.NANO_OF_SECOND);
System.out.println("The current Instant is: " + i);
System.out.println("\nThe Range of MILLI_OF_SECOND is: " + range1);
System.out.println("The Range of MICRO_OF_SECOND is: " + range2);
System.out.println("The Range of NANO_OF_SECOND is: " + range3);
}
}输出结果
The current Instant is: 2019-02-13T09:09:31.210Z The Range of MILLI_OF_SECOND is: 0 - 999 The Range of MICRO_OF_SECOND is: 0 - 999999 The Range of NANO_OF_SECOND is: 0 - 999999999
现在让我们了解上面的程序。
首先，显示当前时刻。然后使用该range()方法打印MILLI_OF_SECOND，MICRO_OF_SECOND和NANO_OF_SECOND的范围。演示这的代码片段如下-
Instant i = Instant.now();
ValueRange range1 = i.range(ChronoField.MILLI_OF_SECOND);
ValueRange range2 = i.range(ChronoField.MICRO_OF_SECOND);
ValueRange range3 = i.range(ChronoField.NANO_OF_SECOND);
System.out.println("The current Instant is: " + i);
System.out.println("\nThe Range of MILLI_OF_SECOND is: " + range1);
System.out.println("The Range of MICRO_OF_SECOND is: " + range2);
System.out.println("The Range of NANO_OF_SECOND is: " + range3);