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 MethodsScanner 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()