java - 获取用户输入并将其分配给不同类中的 HashMap

Question

我正在尝试获取用户输入并将其分配给不同类中的 HashMap 。我的意图是在主类中声明一个映射并将值存储在该映射中，然后通过构造函数将主类映射中收集的数据分配给另一个类中的映射。 map 结构<string, integer>目标是打印两个值而不是仅打印一个值。我该怎么办？到目前为止，我在将值放入 map (oldVal)时遇到了这个特定错误

Error: required: java.lang.string found: java.lang.integer

这是我的代码:
主类 -

import java.util.HashMap;
import java.util.Scanner;
import java.util.Random;

public class Main{

    public static void main(String[] args) throws Exception{
        int choice;
        final int MAX = 999999999;
        boolean loopAgain = true;
        HashMap<String, Integer> mapRatings = new HashMap<>();

           System.out.println("Enter movie rating (PG OR NC): ");
           String rating = input.nextLine();

           System.out.println("Enter the rating age (13 OR 17): ");
           Integer ratingId = Integer.parseInt(input.nextLine());

           String oldVal = mapRatings.put(rating, ratingId);
    }
}     

电影类:

import java.util.*;

public class Movie {
    private String id;
    private String name;
    private String description;
    private String[] genre;
    private String[] actors;
    private String[] language;
    private String countryOfOrigin;
    private Map<String, Integer> ratings;    

//Constructor
    public Movie(String id, String name, String description, String[] genre, String[] actors, String[] language, String countryOfOrigin, Map<String, Integer> ratings){
        this.id = id;
        this.name = name;
        this.description = description;
        this.genre = genre;
        this.actors = actors;
        this.language = language;
        this.countryOfOrigin = countryOfOrigin;
        this.ratings = ratings;
    }

 public void setRatings(Map<String, Integer> ratings){
        this.ratings = ratings;
    }
}

Answer 1

检查Map documentation如下:

V put​(K key, V value)

参数:

key - key with which the specified value is to be associated
value - value to be associated with the specified key

即返回类型应与值的类型匹配。在您的情况下，您的值是 int 类型，因此您应该编写

int oldVal = mapRatings.put(rating, ratingId);