java - 为什么我的程序不等待输入？

Question

我正在尝试获取用户输入并使用正则表达式对其进行验证。但是，当我运行该程序时，它似乎并没有等待接收任何额外的用户输入。相反，我得到了

Exception in thread "main" java.util.NoSuchElementException`

任何关于正在发生的事情的帮助都会很棒!

这是我的代码:

//Retrieve name
System.out.println("What name would you like to search for? (Enter first name only without spaces)");
Scanner input = new Scanner(System.in);
while (!input.hasNext("[A-Za-z]+")) {
    System.out.println("Invalid entry. Please enter first name only.");
    input.next();
}
String name = input.next();
System.out.println("You gave me as input the name:" + name);
}

Answer 1

工作正常。将其作为一个完整的工作类进行尝试(将其保存为 myInput.java，然后使用javac myInput.java编译> ，然后使用java myInput运行它:

import java.io.*;
import java.util.Scanner;
class myInput {
    public static void main(String[] args) {
    //Retrieve name
    System.out.println("What name would you like to search for? (Enter first name only without spaces)");
    Scanner input = new Scanner(System.in);
    while (!input.hasNext("[A-Za-z]+")) {
        System.out.println("Invalid entry. Please enter first name only.");
        input.next();
    }
    String name = input.next();
    System.out.println("You gave me as input the name:" + name);
    }
}

OUTPUT(我首先给出无效输入(test1)，然后正确打印有效(test)):

test1
Invalid entry. Please enter first name only.
test
You gave me as input the name:test