Java不允许我提示变量

Question

我正在创建一个程序来提示用户输入信息，所以我创建了多个变量，然后让程序根据这些变量输出信息。出于某种原因，每当我声明新的年龄变量时，程序都会给我一个奇怪的错误，在线程“main”中说Exception。我试着将第一次扫描关闭到，但不起作用。

我的密码是

package lab3;
import java.util.Scanner;

public class Story {
public static void main (String[] args) {

extract();

}

public static void extract () {

//variable declarations

     Scanner scan = new Scanner(System.in);
        System.out.println("First Name:  ");
        String firstname = scan.next();
        System.out.println("Last Name:  ");
        String lastname = scan.next();
        String output = firstname.substring(0, 1).toUpperCase() + firstname.substring(1) + " "
                + lastname.substring(0, 1).toUpperCase() + lastname.substring(1);
        


        // Input and processing section

        firstname = firstname.trim();
        lastname = lastname.trim();
        // output section

        Scanner scan1 = new Scanner(System.in);
        System.out.println("City and State :  ");
        String city = scan1.next();
        String state = scan1.next();
        scan1.close();
        
        Scanner scan2 = new Scanner(System.in);
        System.out.println("Age :  ");
        int age = scan2.nextInt();
        scan2.close();



        

        
     
    
        
        // output
        System.out.println("There was once a person named " + output + " who lived in " + city + " " + state + " After studying for 2 years at"
                + " a well-known college in " + state + " " +  firstname + " left the United states at age " + age);
    }}

Answer 1

问题是，当你关闭一个物体扫描仪时，它就是底层系统。那是关着的。我已经对close（）的调用进行了注释，您的脚本正在运行。

import java.util.Scanner;

public class Story {
public static void main (String[] args) {

extract();

}

public static void extract () {

//variable declarations

     Scanner scan = new Scanner(System.in);
        System.out.println("First Name:  ");
        String firstname = scan.next();
        System.out.println("Last Name:  ");
        String lastname = scan.next();
        String output = firstname.substring(0, 1).toUpperCase() + firstname.substring(1) + " "
                + lastname.substring(0, 1).toUpperCase() + lastname.substring(1);


        // Input and processing section

        firstname = firstname.trim();
        lastname = lastname.trim();
        // output section

        Scanner scan1 = new Scanner(System.in);
        System.out.println("City and State :  ");
        String city = scan1.next();
        String state = scan1.next();
//        scan1.close();

        Scanner scan2 = new Scanner(System.in);
        System.out.println("Age :  ");
        int age = scan2.nextInt();
 //       scan2.close();

        // output
        System.out.println("There was once a person named " + output + " who lived in " + city + " " + state + " After studying for 2 years at"
                + " a well-known college in " + state + " " +  firstname + " left the United states at age " + age);
    }}