Java Scanner useRadix()用法及代码示例

java.util.Scanner类的useRadix(radix)方法将此扫描程序的默认基数设置为指定的基数。扫描仪的基数会影响其默认数字与正则表达式匹配的元素。

用法:

public Scanner useRadix(int radix)

参数：该函数接受必需的参数基数，该基数指定扫描数字时要使用的基数。

返回值：该函数返回此扫描器对象。

异常：如果基数小于Character.MIN_RADIX或大于Character.MAX_RADIX，则抛出IllegalArgumentException。

以下示例程序旨在说明上述函数：

示例1:

// Java program to illustrate the 
// useRadix() method of Scanner class in Java 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) 
        throws Exception 
    { 
  
        try { 
  
            String s = "Geeksforgeeks has Scanner Class Methods"; 
  
            // create a new scanner 
            // with the specified String Object 
            Scanner scanner = new Scanner(s); 
  
            // print the line of the scanner 
            System.out.println("String:\n"
                               + scanner.nextLine()); 
  
            // display the Old radix 
            System.out.println("\nOld Radix: "
                               + scanner.radix()); 
  
            // change the radix 
            // of the scanner to 12 
            scanner.useRadix(12); 
  
            // display the new radix 
            System.out.println("\nNew Radix: "
                               + scanner.radix()); 
  
            // close the scanner 
            scanner.close(); 
        } 
  
        catch (IllegalArgumentException e) { 
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

输出：

String:
Geeksforgeeks has Scanner Class Methods

Old Radix: 10

New Radix: 12

示例2:显示异常

// Java program to illustrate the 
// useRadix() method of Scanner class in Java 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) 
        throws Exception 
    { 
  
        try { 
  
            String s = "Geeksforgeeks has Scanner Class Methods"; 
  
            // create a new scanner 
            // with the specified String Object 
            Scanner scanner = new Scanner(s); 
  
            // print the line of the scanner 
            System.out.println("String:\n"
                               + scanner.nextLine()); 
  
            // display the Old radix 
            System.out.println("\nOld Radix: "
                               + scanner.radix()); 
  
            // change the radix 
            // of the scanner to 64 
            scanner.useRadix(64); 
  
            // display the new radix 
            System.out.println("\nNew Radix: "
                               + scanner.radix()); 
  
            // close the scanner 
            scanner.close(); 
        } 
  
        catch (IllegalArgumentException e) { 
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

输出：

String:
Geeksforgeeks has Scanner Class Methods

Old Radix: 10
Exception thrown : java.lang.IllegalArgumentException: radix:64

参考： https://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html#useRadix(int)

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注：本文由纯净天空筛选整理自gopaldave大神的英文原创作品 Scanner useRadix() method in Java with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。