Java Instant truncatedTo()用法及代碼示例

Instant類的truncatedTo()方法用於以指定單位獲取此Instant的值。此方法采用參數Unit，即此Instant被截斷為的Unit。它返回帶有指定單位的值的截斷的不可變Instant。

用法:

public Instant truncatedTo(TemporalUnit unit)

參數：此方法采用參數uint，該參數uint是要將此Instant截斷的單位。它不能為空。

返回值：此方法以指定的單位返回不可變的截斷的Instant。

異常：此方法引發以下異常：

DateTimeException：如果單位對於截斷無效。
UnsupportedTemporalTypeException：如果不支持該設備。

以下示例程序旨在說明Instant.truncatedTo()方法：

程序1:

// Java program to demonstrate 
// Instant.truncatedTo() method 
  
import java.time.*; 
import java.time.temporal.ChronoUnit; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // create a Instant object 
        Instant instant 
            = Instant.parse("2018-12-30T09:24:54.63Z"); 
  
        // print instance 
        System.out.println("Instant before"
                           + " truncate: "
                           + instant); 
  
        // truncate to ChronoUnit.HOURS 
        // means unit smaller than Hour 
        // will be Zero 
        Instant returnvalue 
            = instant.truncatedTo(ChronoUnit.HOURS); 
  
        // print result 
        System.out.println("Instant after "
                           + " truncate: "
                           + returnvalue); 
    } 
}

輸出：

Instant before truncate: 2018-12-30T09:24:54.630Z
Instant after  truncate: 2018-12-30T09:00:00Z

程序2:

// Java program to demonstrate 
// Instant.truncatedTo() method 
  
import java.time.*; 
import java.time.temporal.ChronoUnit; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // create a Instant object 
        Instant instant 
            = Instant.parse("2018-12-30T09:24:54.63Z"); 
  
        // print instance 
        System.out.println("Instant before"
                           + " truncate: "
                           + instant); 
  
        // truncate to ChronoUnit.DAYS 
        // means unit smaller than DAY 
        // will be Zero 
        Instant returnvalue 
            = instant.truncatedTo(ChronoUnit.DAYS); 
  
        // print result 
        System.out.println("Instant after "
                           + " truncate: "
                           + returnvalue); 
    } 
}

輸出：

Instant before truncate: 2018-12-30T09:24:54.630Z
Instant after  truncate: 2018-12-30T00:00:00Z

程序3:顯示異常：

// Java program to demonstrate 
// Instant.truncatedTo() method 
  
import java.time.*; 
import java.time.temporal.ChronoUnit; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // create a Instant object 
        Instant instant 
            = Instant.parse("2018-12-30T09:24:54.63Z"); 
  
        try { 
            instant.truncatedTo(ChronoUnit.ERAS); 
        } 
        catch (Exception e) { 
  
            // print result 
            System.out.println("Exception: " + e); 
        } 
    } 
}

輸出：

Exception:
 java.time.temporal.UnsupportedTemporalTypeException:
 Unit is too large to be used for truncation

參考：https://docs.oracle.com/javase/10/docs/api/java/time/Instant.html#truncatedTo(java.time.temporal.TemporalUnit)

相關用法

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