java - 不记得第一个用户输入

Question

我正在尝试获取员工姓名的用户输入，但扫描仪要么不接受名字，要么不记得名字。主要方法

import java.util.Scanner;

public class ToyShop {
    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner in = new Scanner(System.in);
        System.out.println("Please select from the following options");
        System.out.println("1. Add new employee");
        System.out.println("2. Add new customer");
        System.out.println("3. Add new product");
        System.out.println("4. Edit employee");
        System.out.println("5. Edit customer");
        System.out.println("6. Edit product");
        System.out.println("7. Add new transaction");
        System.out.println("8. Display all transactions");
        System.out.println("9. Exit");

        int pick = in.nextInt();

        if(pick == 1) {
            //first name input
            System.out.println("What is the employees first name: ");
            String eFirst = in.nextLine();
            Employee e1 = new Employee();
            e1.setFirst(eFirst);
            in.hasNext();
            //last name input
            System.out.println("What is their last name: ");
            String eLast = in.nextLine();
            e1.setLast(eLast);
            in.hasNext();

            System.out.println(e1.toString() + eFirst);
        }

    }

}

employee class
public class Employee extends Person {

    private static int id;
    private String depart;

    public Employee() {
        this.id = 1000;
        this.depart = "";
        Employee.super.setFirst("");
        Employee.super.setLast("");
    }

    public Employee(int id, String depart, String first, String last) {
        super(first, last);
        this.id = id += 1;
        this.depart = depart;
    }

    /**
     * @return the id
     */
    public int getId() {
        return id += 1;
    }

    /**
     * @return the depart (department)
     */
    public String getDepart() {
        return depart;
    }

    /**
     * @param depart the department to set
     */
    public void setDepart(String depart) {
        this.depart = depart;
    }

    @Override
    public String toString() {
        return "[" + id + "] " + getFirst() + " " + getLast() + ", " + depart;
    }
}

当它打印 e1(员工对象 1)toString 时，它只会打印出名字，如果我删除两行 in.hasNext() ，它将跳过用户输入名字

Answer 1

您的问题是方法 nextInt() 无法像方法 nextLine() 那样正确检测换行符(想象一下用户按下 Enter 按钮)。因此，您需要在其后添加 nextLine() 才能检测换行符输入。方法 hasNext() 不是必需的，因为它仅根据扫描仪 token 的状态返回一个 boolean 值。

int pick = in.nextInt();
in.nextLine();            //this is what's needed to detect the newline

if(pick == 1) {
    //first name input
    System.out.println("What is the employees first name: ");
    String eFirst = in.nextLine();
    e1.setFirst(eFirst);
    //in.hasNext();           (you don't need this)
    //last name input  
    System.out.println("What is their last name: ");
    String eLast = in.nextLine();
    e1.setLast(eLast);
    //in.hasNext();           (you don't need this)

    System.out.println(e1.toString() + eFirst);
}

这将成功检测数字选择、名字和姓氏的输入。