如何使用Java实现多维度哈希映射和前缀查询功能？

class Dimension {
    private String a, b, c;

    // getters and setters
    // ...

    @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);
    }
}

Map<Dimension, String> hashMap = new HashMap<>();
hashMap.put(new Dimension("a", "b", "c"), "u1");
hashMap.put(new Dimension("a", "d", "e"), "u2");
hashMap.put(new Dimension("x", "y", "z"), "v1");

String[] result = hashMap.entrySet().stream()
        .filter(entry -> Objects.equals(entry.getKey().getA(), "a"))
        .map(Map.Entry::getValue)
        .toArray(String[]::new);
System.out.println(Arrays.toString(result)); // 输出 [u1, u2]