Java 8 BigInteger byteValueExact()用法及代碼示例

Java 8中引入了java.math.BigInteger.byteValueExact()。它是一個內置函數，可將BigInteger的值轉換為字節，並檢查是否丟失任何信息。如果BigInteger的值大於127或小於-128，則該方法將拋出ArithmeticException，因為BigInteger不在字節範圍內。

用法:

public byte byteValueExact()

返回值：此方法返回此BigInteger的字節值。

異常：如果BigInteger的值大於127或小於-128，則此方法將引發ArithmeticException，因為此範圍不適合字節範圍。

例：

Input:122
Output:122
Explanation:122 is given as input which is bigInteger
and byte value of 122 is 122

Input:-46
Output:-46
Explanation:-46 is given as input which is bigInteger 
and byte value of -46 is -46

Input:200
Output:ArithmeticException
Explanation:When 200 is tried to convert to Byte,
since 200 > 127 (greater than a Byte's range), 
therefore it throws an arithmetic exception.

以下示例程序旨在說明BigInteger類的byteValueExact()方法：

程序1:演示byteValueExact()方法的正數<127

// Java program to demonstrate byteValueExact() 
// method of BigInteger Class 
  
import java.math.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
        // Creating a BigInteger object 
        BigInteger big; 
        big = new BigInteger("122"); 
  
        // print value of BigInteger 
        System.out.println("BigInteger value:"
                           + big); 
  
        // convert big to the byte value 
        byte b1 = big.byteValueExact(); 
  
        // print byte value 
        System.out.println("Byte converted value:"
                           + b1); 
    } 
}

輸出：

BigInteger value:122
Byte converted value:122

程序2:演示byteValueExact()方法用於負數> -128

// Java program to demonstrate byteValueExact() 
// method of BigInteger Class 
  
import java.math.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Creating a BigInteger object 
        BigInteger big = new BigInteger("-46"); 
  
        // print value of BigInteger 
        System.out.println("BigInteger value:"
                           + big); 
  
        // convert big to the byte value 
        byte b1 = big.byteValueExact(); 
  
        // print byte value 
        System.out.println("Byte converted value:"
                           + b1); 
    } 
}

輸出：

BigInteger value:-46
Byte converted value:-46

程序3:演示用於負數<-128的byteValueExact()方法。它將引發算術異常

// Java program to demonstrate byteValueExact() 
// method of BigInteger Class 
  
import java.math.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Creating a BigInteger object 
        BigInteger big = new BigInteger("-200"); 
  
        // print value of BigInteger 
        System.out.println("BigInteger value:"
                           + big); 
  
        try { 
            // convert big to the byte value 
            byte b1 = big.byteValueExact(); 
  
            // print byte value 
            System.out.println("Byte converted value:"
                               + b1); 
        } 
        catch (Exception e) { 
            System.out.println("Exception:" + e); 
        } 
    } 
}

輸出：

BigInteger value:-200
Exception:java.lang.ArithmeticException:BigInteger out of byte range

程序4:演示byteValueExact()方法用於正數> 127。它將引發算術異常

// Java program to demonstrate byteValueExact() 
// method of BigInteger Class 
  
import java.math.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Creating a BigInteger object 
        BigInteger big = new BigInteger("200"); 
  
        // print value of BigInteger 
        System.out.println("BigInteger value:"
                           + big); 
  
        try { 
            // convert big to the byte value 
            byte b1 = big.byteValueExact(); 
  
            // print byte value 
            System.out.println("Byte converted value:"
                               + b1); 
        } 
        catch (Exception e) { 
            System.out.println("Exception:" + e); 
        } 
    } 
}

輸出：

BigInteger value:200
Exception:java.lang.ArithmeticException:BigInteger out of byte range

參考： https://docs.oracle.com/javase/8/docs/api/java/math/BigInteger.html#byteValueExact-

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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 Java 8 | BigInteger byteValueExact() method 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。