Java中的即时 isBefore() 方法和示例

Instant 类的isBefore()方法检查此即时时间线位置是否在作为参数传递的瞬间之前。如果此即时时间线位置在作为参数传递的即时之前，则该方法将返回 true，否则返回 false。比较基于时刻的时间线位置。

句法：

public boolean isBefore(Instant otherInstant)

参数：此方法接受一个参数otherInstant ，它是要比较的另一个瞬间。它不应该为空。

返回：如果此时刻在指定时刻之前，则此方法返回true 。

异常：如果 otherInstant 为 null，则此方法抛出NullPointerException 。

下面的程序说明了 isBefore() 方法：

方案一：

// Java program to demonstrate
// Instant.isBefore() method
  
import java.time.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // create a Instant object
        Instant instant1
            = Instant.parse("2018-12-30T09:24:54.63Z");
  
        // create other Instant
        Instant instant2
            = Instant.parse("2018-12-31T01:34:00.63Z");
  
        // print instances
        System.out.println("Instance 1: " + instant1);
        System.out.println("Instance 2: " + instant2);
  
        // check if instant1 is after instant2
        // using isAfter()
        boolean value = instant1.isBefore(instant2);
  
        // print result
        System.out.println("Is Instant1 before Instant2: "
                           + value);
    }
}

输出：

Instance 1: 2018-12-30T09:24:54.630Z
Instance 2: 2018-12-31T01:34:00.630Z
Is Instant1 before Instant2: true

方案二：

// Java program to demonstrate
// Instant.isBefore() method
  
import java.time.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // create a Instant object
        Instant instant1
            = Instant.parse("2018-11-27T09:24:54.63Z");
  
        // create other Instant
        Instant instant2 = Instant.now();
  
        // print instances
        System.out.println("Instance 1: " + instant1);
        System.out.println("Instance 2: " + instant2);
  
        // check if instant1 is after instant2
        // using isAfter()
        boolean value = instant1.isBefore(instant2);
  
        // print result
        System.out.println("Is Instant1 before Instant2: "
                           + value);
    }
}

输出：

Instance 1: 2018-11-27T09:24:54.630Z
Instance 2: 2018-11-27T04:55:36.127Z
Is Instant1 before Instant2: false

程序 3：显示 isBefore() 抛出的异常

// Java program to demonstrate
// Instant.isBefore() method
  
import java.time.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // create a Instant object
        Instant instant1 = Instant.parse("2018-10-30T19:34:50.63Z");
  
        // create other Instant
        Instant instant2 = null;
  
        try {
  
            // print instances
            System.out.println("Instance 1: " + instant1);
            System.out.println("Instance 2: " + instant2);
  
            // check if instant1 is after instant2
            // using isAfter()
            boolean value = instant1.isBefore(instant2);
        }
        catch (Exception e) {
            // print result
            System.out.println("Exception: " + e);
        }
    }
}

输出：

Instance 1: 2018-10-30T19:34:50.630Z
Instance 2: null
Exception: java.lang.NullPointerException

参考资料：https: Java Java.time.Instant)