生成lru算法Java代码

好的，我可以回答这个问题。以下是一个简单的 LRU 算法的 Java 代码实现：

import java.util.HashMap;
import java.util.Map;

public class LRUCache<K, V> {
    private final int capacity;
    private final Map<K, Node<K, V>> cache;
    private Node<K, V> head;
    private Node<K, V> tail;

    public LRUCache(int capacity) {
        this.capacity = capacity;
        cache = new HashMap<>(capacity);
    }

    public V get(K key) {
        Node<K, V> node = cache.get(key);
        if (node == null) {
            return null;
        }
        moveToHead(node);
        return node.value;
    }

    public void put(K key, V value) {
        Node<K, V> node = cache.get(key);
        if (node == null) {
            node = new Node<>(key, value);
            cache.put(key, node);
            addToHead(node);
            if (cache.size() > capacity) {
                removeTail();
            }
        } else {
            node.value = value;
            moveToHead(node);
        }
    }

    private void addToHead(Node<K, V> node) {
        if (head == null) {
            head = node;
            tail = node;
        } else {
            node.next = head;
            head.prev = node;
            head = node;
        }
    }

    private void removeNode(Node<K, V> node) {
        if (node == head) {
            head = node.next;
        } else if (node == tail) {
            tail = node.prev;
        } else {
            node.prev.next = node.next;
            node.next.prev = node.prev;
        }
    }

    private void moveToHead(Node<K, V> node) {
        removeNode(node);
        addToHead(node);
    }

    private void removeTail() {
        cache.remove(tail.key);
        if (tail == head) {
            tail = null;
            head = null;
        } else {
            tail = tail.prev;
            tail.next = null;
        }
    }

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

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

这个类实现了一个 LRU 缓存，使用双向链表和哈希表来实现。它有两个主要的方法：`get` 和 `put`。`get` 方法根据给定的键返回缓存中对应的值，如果缓存中没有该键，则返回 null。`put` 方法将给定的键值对添加到缓存中，如果缓存已满，则删除最近最少使用的键值对。