OptionalLong幫助我們創建一個可能包含或可能不包含long值的對象。 getAsLong()方法返回值如果OptionalLong對象中存在一個值,否則拋出NoSuchElementException。
用法:
public long getAsLong()
參數:此方法不接受任何內容。
返回值:此方法返回此OptionalLong描述的值。
異常:如果不存在任何值,則此方法將引發NoSuchElementException
以下示例程序旨在說明getAsLong()方法:
示例1:
// Java program to demonstrate
// OptionalLong.getAsLong() method
import java.util.OptionalLong;
public class GFG {
public static void main(String[] args)
{
// Create an OptionalLong instance
OptionalLong opLong = OptionalLong.of(445325);
System.out.println("OptionalLong: "
+ opLong.toString());
// Get value in this instance
// using getAsLong()
System.out.println("Value in OptionalLong = "
+ opLong.getAsLong());
}
}
輸出:
OptionalLong: OptionalLong[445325] Value in OptionalLong = 445325
示例2:
// Java program to demonstrate
// OptionalLong.getAsLong() method
import java.util.OptionalLong;
public class GFG {
public static void main(String[] args)
{
try {
// Create an OptionalLong instance
OptionalLong opLong = OptionalLong.empty();
System.out.println("OptionalLong: "
+ opLong.toString());
// Get value in this instance
// using getAsLong()
System.out.println("Value in OptionalLong = "
+ opLong.getAsLong());
}
catch (Exception e) {
System.out.println("Exception: " + e);
}
}
}
輸出:
OptionalLong: OptionalLong.empty Exception: java.util.NoSuchElementException: No value present
參考文獻: https://docs.oracle.com/javase/10/docs/api/java/util/OptionalLong.html#getAsLong()
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注:本文由純淨天空篩選整理自AmanSingh2210大神的英文原創作品 OptionalLong getAsLong() method in Java with examples。非經特殊聲明,原始代碼版權歸原作者所有,本譯文未經允許或授權,請勿轉載或複製。