Question

我试图获取用户输入并使用正则表达式对其进行验证。但是，当我运行程序时，它似乎没有等待接收任何其他用户输入。相反，我得到了

线程中的异常＆＃34; main＆＃34; java.util.NoSuchElementException`

对正在发生的事情的任何帮助都会很棒！

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。尝试将其作为完全正常工作的类（将其保存为 myInput.java，然后使用javac myInput.java 编译，然后使用运行 em> java myInput）：

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（测试））：

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

为什么我的程序不等待输入？

1 个答案: