diff --git a/w8/Cache.class b/w8/Cache.class
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diff --git a/w8/Cache.java b/w8/Cache.java
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+++ b/w8/Cache.java
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+import java.util.HashMap;
+import java.util.Map;
+
+public class Cache<K, V> {
+    // 用 HashMap 存储缓存数据
+    private final Map<K, V> cache;
+
+    // 构造方法：初始化缓存
+    public Cache() {
+        cache = new HashMap<>();
+    }
+
+    // 存入缓存
+    public void put(K key, V value) {
+        cache.put(key, value);
+    }
+
+    // 从缓存读取
+    public V get(K key) {
+        return cache.get(key);
+    }
+
+    // 判断缓存是否存在某个 key
+    public boolean containsKey(K key) {
+        return cache.containsKey(key);
+    }
+
+    // 移除缓存
+    public void remove(K key) {
+        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 main 方法
+    public static void main(String[] args) {
+        Cache<String, Integer> studentScore = new Cache<>();
+
+        // 存入数据
+        studentScore.put("张三", 90);
+        studentScore.put("李四", 85);
+
+        // 读取数据
+        System.out.println("张三的分数：" + studentScore.get("张三"));
+        System.out.println("缓存大小：" + studentScore.size());
+
+        // 判断是否存在
+        System.out.println("是否包含李四：" + studentScore.containsKey("李四"));
+
+        // 移除数据
+        studentScore.remove("李四");
+        System.out.println("移除后缓存大小：" + studentScore.size());
+    }
+}
diff --git a/w8/Pair.class b/w8/Pair.class
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diff --git a/w8/Pair.java b/w8/Pair.java
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+public class Pair<K, V> {
+    private K key;
+    private V value;
+    public Pair(K key, V value) {
+        this.key = key;
+        this.value = value;
+    }
+    public void swap() {
+        K temp = key;
+        key = (K)value;
+        value = (V)temp;
+    }
+    public K getKey() { return key; }
+    public V getValue() { return value; }
+    public static void main(String[] args) {
+        Pair<Object, Object> pair = new Pair<>("Name", 18);
+        System.out.println("Before swap: key=" + pair.getKey() + ", value=" + pair.getValue());
+        pair.swap();
+        System.out.println("After swap: key=" + pair.getKey() + ", value=" + pair.getValue());
+    }
+}