Java 电话簿不接受来自 2 个字符串的输入

Question

这是我正在为 java 电话簿工作的项目。 我试图编译，但是当我尝试添加第二个字符串时，它只是跳过它。

import java.util.HashMap;
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
    Scanner s = new Scanner(System.in);
    HashMap<String, String> PhoneBook = new HashMap<String, String>();
        while (true == true){
            System.out.println("Main Menu: ");
            System.out.println("1. Add to phonebook");
            System.out.println("2. Remove from phonebook");
            System.out.println("3. Read the phonebook");
            System.out.println("4. Clear entire phonebook");
            int choice = s.nextInt();
            if (choice == 1) {
                System.out.println("Please enter the name of the person: ");
                String name = s.nextLine();
                PhoneBook.put(name, "Blah");
                System.out.println("Please enter the number of the person: ");
                String number = s.nextLine();
                PhoneBook.put(name, number);

            }

        }

    }

Answer 1

这与您尝试插入重复条目有关

if (choice == 1) {
   System.out.println("Please enter the name of the person: ");
   String name = s.nextLine();
   PhoneBook.put(name, "Blah"); //first entry of name
   System.out.println("Please enter the number of the person: ");
   String number = s.nextLine();
   PhoneBook.put(name, number); //second duplicate entry!

}

Answer 2

A) 将具有无效值的键放入哈希映射然后重写该值似乎效率低下。

import java.util.HashMap;
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
    Scanner s = new Scanner(System.in);
    HashMap<String, String> PhoneBook = new HashMap<String, String>();
        while (true == true){
            System.out.println("Main Menu: ");
            System.out.println("1. Add to phonebook");
            System.out.println("2. Remove from phonebook");
            System.out.println("3. Read the phonebook");
            System.out.println("4. Clear entire phonebook");
            int choice = s.nextInt();
            if (choice == 1) {
                System.out.println("Please enter the name of the person: ");
                String name = s.nextLine();
                System.out.println("Please enter the number of the person: ");
                String number = s.nextLine();
                PhoneBook.put(name, number);

            }

    }

}

B）我认为这应该可以帮助您解决问题，但如果没有，请告诉我，我可以重新编辑我的答案。 我认为你只是把值放在同一个键上，这就是为什么你认为你没有得到第二个值