Today, when using the scanner class to obtain data from the console, a Java. Util. NoSuchElementException exception was reported

Here is the problem code

public static void init(LinkList l){
        for(int i=0;i<3;i++){
            System.out.println("Please enter the "+i+" value");
            Scanner temp=new Scanner(System.in);
            int len=temp.nextInt();
            l.addNode(len);
            temp.close();
        }
    }

When you want to input the second data, you will report an error. This is abnormal information

Please enter the 0th value
2
Please enter the 1st value
Exception in thread "main" java.util.NoSuchElementException
    at java.util.Scanner.throwFor(Unknown Source)
    at java.util.Scanner.next(Unknown Source)
    at java.util.Scanner.nextInt(Unknown Source)
    at java.util.Scanner.nextInt(Unknown Source)
    at com.zji.List.LinkList.init(LinkList.java:33)
    at com.zji.List.LinkList.main(LinkList.java:60)

This is because temp. Close() is closed in the for loop. Just write temp. Close() outside the for loop

At first, I thought I’d cycle through a new scanner and turn it off. Can’t I turn it on again?No! This is because your scanner. Close will call the system. In. Close method to close the system. In. After you, new scanner will not help you open the system. In stream, so an error is reported

The following is the source code of the close method, which you can refer to

public void close() {
      if (closed)
          return;
      if (source instanceof Closeable) {
          try {
              ((Closeable)source).close();
          } catch (IOException ioe) {
              lastException = ioe;
          }
      }
      sourceClosed = true;
      source = null;
      closed = true;
  }