创建自定义Hashmap()

public class CustomHashMap<K, V> {
    private int size;
    private Node<K, V>[] buckets;

    public CustomHashMap(int capacity) {
        size = 0;
        buckets = new Node[capacity];
    }

    public void put(K key, V value) {
        int index = Math.abs(key.hashCode()) % buckets.length;
        Node<K, V> node = buckets[index];
        while (node != null) {
            if (node.key.equals(key)) {
                node.value = value;
                return;
            }
            node = node.next;
        }
        Node<K, V> newNode = new Node<>(key, value);
        newNode.next = buckets[index];
        buckets[index] = newNode;
        size++;
    }

    public V get(K key) {
        int index = Math.abs(key.hashCode()) % buckets.length;
        Node<K, V> node = buckets[index];
        while (node != null) {
            if (node.key.equals(key)) {
                return node.value;
            }
            node = node.next;
        }
        return null;
    }

    private static class Node<K, V> {
        K key;
        V value;
        Node<K, V> next;

        public Node(K key, V value) {
            this.key = key;
            this.value = value;
            this.next = null;
        }
    }
}