Loading... 多说无益，`LRU` 是啥网上都能查到，直接贴代码。 ## 代码实现 <div class="tip inlineBlock info"> 这里分别提供了同步和异步的实现，异步实现中通过 `synchronized` 包实现加锁 </div> ```dart import 'dart:collection'; import 'package:synchronized/synchronized.dart'; class LRUCache<K, V> { final int maxSize; final LinkedHashMap<K, V> _map; LRUCache({this.maxSize = 1000}) : _map = LinkedHashMap<K, V>(); V? get(K key) { if (!_map.containsKey(key)) return null; final value = _map.remove(key) as V; _map[key] = value; return value; } void put(K key, V value) { if (_map.containsKey(key)) { _map.remove(key); } else if (_map.length >= maxSize) { _map.remove(_map.keys.first); } _map[key] = value; } void clear() => _map.clear(); int size() => _map.length; @override String toString() => _map.toString(); } class AsyncLRUCache<K, V> { final int maxSize; final LinkedHashMap<K, V> _map = LinkedHashMap<K, V>(); final Lock _lock = Lock(); AsyncLRUCache({this.maxSize = 1000}); Future<V?> get(K key) async { return await _lock.synchronized(() async { if (!_map.containsKey(key)) return null; final value = _map.remove(key) as V; _map[key] = value; return value; }); } Future<void> put(K key, V value) async { await _lock.synchronized(() async { if (_map.containsKey(key)) { _map.remove(key); } else if (_map.length >= maxSize) { _map.remove(_map.keys.first); } _map[key] = value; }); } Future<void> clear() async { await _lock.synchronized(() => _map.clear()); } Future<int> size() async { return await _lock.synchronized(() => _map.length); } @override String toString() => _map.toString(); } ``` © 允许规范转载 打赏 赞赏作者 微信 赞
