在 Java 中实例化和初始化 "multi-level" 个地图

Question

我试图在不使用大量 if/elses 的情况下解决 This problem in BeeCrowd。

它包括从使用中读取 3 个输入，例如：

vertebrado
ave
carnivoro

并输出这些输入对应的单词。

aguia

我 python 比 java 了解更多，这将是我在 python 中的解决方案（有效）：

dict = {
  "vertebrado": {
    "ave": {
      "carnivoro": "aguia",
      "onivoro": "pomba"
    },
    "mamifero": {
      "onivoro": "homem",
      "herbivoro": "vaca"
    }
  },
  "invertebrado": {
    "inseto": {
      "hematofago": "pulga",
      "herbivoro": "lagarta"
    },
    "anelideo": {
      "hematofago": "sanguessuga",
      "onivoro": "minhoca"
    }
  }
}

word1 = input()
word2 = input()
word3 = input()

word = dict[word1][word2][word3]

print(word)

但是我正在努力在 Java 中编写一个好的解决方案。这是我当前的 Java 解决方案（也有效）：

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

public class Main {
    public static void main (String[]args) {
        Scanner scanner = new Scanner(System.in);
        String word1 = new String(scanner.nextLine());
        String word2 = new String(scanner.nextLine());
        String word3 = new String(scanner.nextLine());
        
        HashMap<String, HashMap<String, HashMap<String, String>>> dict = new HashMap();
        dict.put("vertebrado",  new HashMap<String, HashMap<String, String>>());
        dict.put("invertebrado", new HashMap<String, HashMap<String, String>>());
        
        dict.get("vertebrado").put("ave", new HashMap<String, String>());
        dict.get("vertebrado").put("mamifero", new HashMap<String, String>());
        
        dict.get("invertebrado").put("inseto", new HashMap<String, String>());
        dict.get("invertebrado").put("anelideo", new HashMap<String, String>());
        
        dict.get("vertebrado").get("ave").put("carnivoro", "aguia");
        dict.get("vertebrado").get("ave").put("onivoro", "pomba");
        dict.get("vertebrado").get("mamifero").put("onivoro", "homem");
        dict.get("vertebrado").get("mamifero").put("herbivoro", "vaca");
        
        dict.get("invertebrado").get("inseto").put("hematofago", "pulga");
        dict.get("invertebrado").get("inseto").put("herbivoro", "lagarta");
        dict.get("invertebrado").get("anelideo").put("hematofago", "sanguessuga");
        dict.get("invertebrado").get("anelideo").put("onivoro", "minhoca");
        
        
        String word = dict.get(word1).get(word2).get(word3);
        
        System.out.println(word);
    }
}

该解决方案的明显问题是，以这种方式填充字典是不切实际的。代码已经很大了。如果dict有很多值，有很多“深度”，维护起来会很麻烦。

有什么办法可以减少吗？ IE，在几行中声明和初始化 dict？

Answer 1

按照 MC Emperor 的建议使用 Map.of():

Map<String, Map<String, Map<String, String>>> dict = Map.of(
    "vertebrado",
        Map.of(
            "ave",
                Map.of(
                    "carnivoro", "aguia",
                    "onivoro", "pomba"
                ),
            "mamifero",
                Map.of("onivoro","homem",
                        "herbivoro","vaca"
                )
        ),
    "invertebrado",
        Map.of(
            "inseto",
                Map.of(
                    "hematofago", "pulga",
                    "herbivoro", "lagarta"
                ),
            "anelideo",
                Map.of(
                    "hematofago","sanguessuga",
                    "onivoro","minhoca"
                )
        )
);

与使用 json 文件相比，这还可以让您在进行时进行类型检查，尽管为了真正的类型安全，您需要引入名为 Phylum 的类、Class 和 Order 来包装你的字符串，而不是留下“字符串类型”的值。

在 Java 中实例化和初始化 "multi-level" 个地图

Instantiate and initialize "multi-level" maps in Java

java