diff --git a/w8/Main.java b/w8/Main.java
new file mode 100644
index 0000000..31e0e90
--- /dev/null
+++ b/w8/Main.java
@@ -0,0 +1,62 @@
+import java.util.Optional;
+
+public class Main {
+
+    public static void main(String[] args) {
+        System.out.println("===== Pair<K,V> 测试 =====");
+        testPair();
+
+        System.out.println();
+        System.out.println("===== Cache<K,V> 测试 =====");
+        testCache();
+    }
+
+    static void testPair() {
+        // 基本用法
+        Pair<String, Integer> p1 = new Pair<>("age", 20);
+        System.out.println("原始: " + p1);
+
+        Pair<Integer, String> p2 = p1.swap();
+        System.out.println("swap: " + p2);
+
+        // 不同类型组合
+        Pair<String, Boolean> p3 = new Pair<>("isStudent", true);
+        Pair<Boolean, String> p4 = p3.swap();
+        System.out.println("原始: " + p3 + " → swap: " + p4);
+    }
+
+    static void testCache() {
+        // 容量为 3 的 LRU 缓存
+        Cache<String, String> cache = new Cache<>(3);
+
+        cache.put("a", "Apple");
+        cache.put("b", "Banana");
+        cache.put("c", "Cherry");
+        System.out.println("初始状态: " + cache);
+
+        // 访问 a，使其成为最近使用
+        cache.get("a");
+
+        // 放入第4个，b 是最久未使用的，会被淘汰
+        cache.put("d", "Durian");
+        System.out.println("放入 d 后 (b 应被淘汰): " + cache);
+        System.out.println("b 是否存在: " + cache.containsKey("b")); // false
+        System.out.println("a 是否存在: " + cache.containsKey("a")); // true
+
+        // Optional 用法演示
+        Optional<String> val = cache.get("c");
+        val.ifPresent(v -> System.out.println("获取 c: " + v));
+        cache.get("x").ifPresentOrElse(
+            v -> System.out.println("获取 x: " + v),
+            ()  -> System.out.println("获取 x: 不存在（缓存未命中）")
+        );
+
+        // 整数缓存
+        Cache<Integer, Double> numCache = new Cache<>(2);
+        numCache.put(1, 3.14);
+        numCache.put(2, 2.71);
+        numCache.put(3, 1.41); // 1 被淘汰
+        System.out.println("数值缓存: " + numCache);
+        System.out.println("key=1 存在: " + numCache.containsKey(1)); // false
+    }
+}
diff --git a/w8/Pair.java b/w8/Pair.java
new file mode 100644
index 0000000..5299346
--- /dev/null
+++ b/w8/Pair.java
@@ -0,0 +1,26 @@
+/**
+ * 泛型键值对 Pair<K, V>
+ * 支持 swap() 方法返回键值互换后的新 Pair
+ */
+public class Pair<K, V> {
+    private K key;
+    private V value;
+
+    public Pair(K key, V value) {
+        this.key = key;
+        this.value = value;
+    }
+
+    public K getKey()   { return key; }
+    public V getValue() { return value; }
+
+    /** 返回键值互换的新 Pair<V, K> */
+    public Pair<V, K> swap() {
+        return new Pair<>(value, key);
+    }
+
+    @Override
+    public String toString() {
+        return "Pair(" + key + ", " + value + ")";
+    }
+}
diff --git a/w8/ScoreReader.java b/w8/ScoreReader.java
new file mode 100644
index 0000000..323a0a5
--- /dev/null
+++ b/w8/ScoreReader.java
@@ -0,0 +1,45 @@
+package org.example;
+
+import java.io.BufferedReader;
+import java.io.FileNotFoundException;
+import java.io.FileReader;
+import java.io.IOException;
+
+public class ScoreReader {
+    public static void main(String[] args) {
+
+        int sum = 0;
+        int count = 0;
+
+        // try-with-resources：自动关闭流，不需要手动 br.close()
+        try (BufferedReader br = new BufferedReader(new FileReader("scores.txt"))) {
+
+            String line;
+            while ((line = br.readLine()) != null) {
+                try {
+                    sum += Integer.parseInt(line.trim());
+                    count++;
+                } catch (NumberFormatException e) {
+                    // 处理数字格式错误
+                    System.out.println("跳过无效数据：" + line);
+                }
+            }
+
+            if (count > 0) {
+                double average = (double) sum / count;
+                System.out.println("总分：" + sum);
+                System.out.println("人数：" + count);
+                System.out.printf("平均分：%.2f%n", average);
+            } else {
+                System.out.println("文件中没有有效成绩。");
+            }
+
+        } catch (FileNotFoundException e) {
+            // 处理文件不存在
+            System.out.println("错误：找不到文件 scores.txt，请检查路径。");
+        } catch (IOException e) {
+            // 处理读取错误
+            System.out.println("错误：读取文件时发生异常：" + e.getMessage());
+        }
+    }
+}
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