java/W8/Cache.java

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

public class Cache<K, V> {
    private final Map<K, V> cache;

    public Cache() {
        cache = new HashMap<>();
    }

    // 存入缓存
    public void put(K key, V value) {
        cache.put(key, value);
    }

    // 读取缓存
    public V get(K key) {
        return cache.get(key);
    }

    // 移除缓存
    public V remove(K key) {
        return cache.remove(key);
    }

    // 清空缓存
    public void clear() {
        cache.clear();
    }

    // 获取缓存大小
    public int size() {
        return cache.size();
    }

    // 测试
    public static void main(String[] args) {
        Cache<String, Integer> ageCache = new Cache<>();
        ageCache.put("张三", 20);
        ageCache.put("李四", 22);

        System.out.println("张三的年龄：" + ageCache.get("张三"));
        System.out.println("缓存大小：" + ageCache.size());

        ageCache.remove("李四");
        System.out.println("移除李四后缓存大小：" + ageCache.size());
    }
}