如何利用哈希映射实现多维度到唯一值的映射并查询前缀相关结果？

import java.util.Objects;

class Dimension {
    String a, b, c;

    // Getters and setters omitted for brevity

    @Override
    public int hashCode() {
        return Objects.hash(a, b, c);
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) return true;
        if (obj == null || getClass() != obj.getClass()) return false;
        Dimension other = (Dimension) obj;
        return Objects.equals(a, other.a) && Objects.equals(b, other.b) && Objects.equals(c, other.c);
    }
}

import java.util.*;
import java.util.stream.*;

public class MultiDimensionMapping {
    public static void main(String[] args) {
        Map<Dimension, String> hashMap = new HashMap<>();
        hashMap.put(new Dimension() {{ a = "a"; b = "b"; }}, "u1");
        hashMap.put(new Dimension() {{ a = "a"; c = "c"; }}, "u2");
        hashMap.put(new Dimension() {{ a = "x"; b = "y"; }}, "v1");

        String prefix = "a";
        String[] result = hashMap.entrySet().stream()
                .filter(entry -> entry.getKey().a.equals(prefix))
                .map(Map.Entry::getValue)
                .toArray(String[]::new);

        System.out.println(Arrays.toString(result)); // Output: [u1, u2]
    }
}