Java Scanner hasNextLine()用法及代码示例

如果此扫描器的输入中还有另一行，则java.util.Scanner类的hasNextLine()方法将返回true。等待输入时，此方法可能会阻塞。扫描仪不会越过任何输入。

用法:

public boolean hasNextLine()

参数：该函数不接受任何参数。

返回值：当且仅当此扫描仪具有另一行输入时，此函数才返回true

异常注意：如果关闭此扫描器，则此函数将引发IllegalStateException。

以下示例程序旨在说明上述函数：

示例1:

// Java program to illustrate the 
// hasNextLine() method of Scanner class in Java 
// without parameter 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) 
        throws Exception 
    { 
  
        String s = "gfg 2 geeks!"; 
  
        // new scanner with the 
        // specified String Object 
        Scanner scanner = new Scanner(s); 
  
        // use US locale to interpret Lines in a string 
        scanner.useLocale(Locale.US); 
  
        // iterate till end 
        while (scanner.hasNextLine()) { 
  
            // print what is scanned 
            System.out.println(scanner.nextLine()); 
        } 
  
        // close the scanner 
        scanner.close(); 
    } 
}

输出：

gfg 2 geeks!

示例2:演示异常的程序

// Java program to illustrate the 
// hasNextLine() method of Scanner class in Java 
// without parameter 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) 
        throws Exception 
    { 
        try { 
  
            String s = "gfg 2 geeks!"; 
  
            // new scanner with the 
            // specified String Object 
            Scanner scanner = new Scanner(s); 
  
            // use US locale to interpret Lines in a string 
            scanner.useLocale(Locale.US); 
  
            scanner.close(); 
  
            // iterate till end 
            while (scanner.hasNextLine()) { 
  
                // print what is scanned 
                System.out.println(scanner.nextLine()); 
            } 
  
            // close the scanner 
            scanner.close(); 
        } 
        catch (IllegalStateException e) { 
            System.out.println("Exception is: " + e); 
        } 
    } 
}

输出：

Exception is: java.lang.IllegalStateException: Scanner closed

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

相关用法

注：本文由纯净天空筛选整理自gopaldave大神的英文原创作品 Scanner hasNextLine() 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。