Java Scanner close()方法及示例

java.util.Scanner 类的 close() 方法可以关闭已经打开的扫描仪。如果扫描器已经被关闭，那么在调用这个方法时，它将不会产生任何影响。

语法

public void close()

返回值： 该函数不返回任何值。

以下程序说明了上述函数。

程序1 :

// Java program to illustrate the
// close() method of Scanner class in Java
  
import java.util.*;
  
public class GFG1 {
    public static void main(String[] argv)
        throws Exception
    {
  
        try {
  
            // Get the string
            String s = "Geeksforgeeks has Scanner Class Methods";
  
            // create a new scanner
            // with the specified String Object
            Scanner scanner = new Scanner(s);
  
            // print the next line of the string
            System.out.println("Scanner: "
                               + scanner.nextLine());
  
            // close the scanner
            scanner.close();
  
            System.out.println("\nScanner Closed.\n");
  
            System.out.println("Trying to use scanner"
                               + " after closing.");
  
            // print the next line of the string
            System.out.println(scanner.nextLine());
        }
  
        catch (Exception e) {
            System.out.println("Exception thrown:\n" + e);
        }
    }
}

输出:

Scanner: Geeksforgeeks has Scanner Class Methods

Scanner Closed.

Trying to use scanner after closing.
Exception thrown:
java.lang.IllegalStateException: Scanner closed

**参考资料: ** https://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html#close()