From 422820bcce234f98650d769cff02ea305e954d72 Mon Sep 17 00:00:00 2001
From: LiuZihan <1353843969@qq.com>
Date: Wed, 29 Apr 2026 21:51:20 +0800
Subject: [PATCH] =?UTF-8?q?=E4=B8=8A=E4=BC=A0=E6=96=87=E4=BB=B6=E8=87=B3?=
 =?UTF-8?q?=20'w8'?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 w8/Cache.java                 | 75 +++++++++++++++++++++++++++++++++++
 w8/GenericReflectionDemo.java | 37 +++++++++++++++++
 w8/Pair.java                  | 33 +++++++++++++++
 3 files changed, 145 insertions(+)
 create mode 100644 w8/Cache.java
 create mode 100644 w8/GenericReflectionDemo.java
 create mode 100644 w8/Pair.java

diff --git a/w8/Cache.java b/w8/Cache.java
new file mode 100644
index 0000000..ffc1f18
--- /dev/null
+++ b/w8/Cache.java
@@ -0,0 +1,75 @@
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+public class Cache<K, V> {
+    private final Map<K, V> store = new HashMap<>();
+    private final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+
+    public void put(K key, V value) {
+        if (key == null || value == null)
+            throw new IllegalArgumentException("Key and value must not be null");
+        lock.writeLock().lock();
+        try {
+            store.put(key, value);
+        } finally {
+            lock.writeLock().unlock();
+        }
+    }
+
+    public V get(K key) {
+        lock.readLock().lock();
+        try {
+            return store.get(key);
+        } finally {
+            lock.readLock().unlock();
+        }
+    }
+
+    public boolean containsKey(K key) {
+        lock.readLock().lock();
+        try {
+            return store.containsKey(key);
+        } finally {
+            lock.readLock().unlock();
+        }
+    }
+
+    public V remove(K key) {
+        lock.writeLock().lock();
+        try {
+            return store.remove(key);
+        } finally {
+            lock.writeLock().unlock();
+        }
+    }
+
+    public void clear() {
+        lock.writeLock().lock();
+        try {
+            store.clear();
+        } finally {
+            lock.writeLock().unlock();
+        }
+    }
+
+    public int size() {
+        lock.readLock().lock();
+        try {
+            return store.size();
+        } finally {
+            lock.readLock().unlock();
+        }
+    }
+
+    public static void main(String[] args) {
+        Cache<String, Integer> cache = new Cache<>();
+        cache.put("one", 1);
+        cache.put("two", 2);
+        System.out.println(cache.get("one"));
+        System.out.println(cache.get("two"));
+        cache.remove("one");
+        System.out.println(cache.containsKey("one"));
+        System.out.println("Cache size: " + cache.size());
+    }
+}
\ No newline at end of file
diff --git a/w8/GenericReflectionDemo.java b/w8/GenericReflectionDemo.java
new file mode 100644
index 0000000..a559da2
--- /dev/null
+++ b/w8/GenericReflectionDemo.java
@@ -0,0 +1,37 @@
+import java.lang.reflect.*;
+import java.util.*;
+
+public class GenericReflectionDemo {
+    private Map<String, List<Integer>> complexField;
+
+    public List<Double> process(Map<String, ? extends Number> map, int value) {
+        return new ArrayList<>();
+    }
+
+    public static void main(String[] args) throws NoSuchFieldException, NoSuchMethodException {
+        Field field = GenericReflectionDemo.class.getDeclaredField("complexField");
+        Type genericType = field.getGenericType();
+        System.out.println("===== 字段泛型信息 =====");
+        if (genericType instanceof ParameterizedType) {
+            ParameterizedType pt = (ParameterizedType) genericType;
+            System.out.println("原始类型: " + pt.getRawType());
+            System.out.println("键的类型: " + pt.getActualTypeArguments()[0]);
+            System.out.println("值的类型: " + pt.getActualTypeArguments()[1]);
+        }
+
+        Method method = GenericReflectionDemo.class.getDeclaredMethod("process", Map.class, int.class);
+        Type returnType = method.getGenericReturnType();
+        System.out.println("\n===== 方法返回类型泛型 =====");
+        System.out.println("返回类型: " + returnType);
+
+        Type[] paramTypes = method.getGenericParameterTypes();
+        System.out.println("\n===== 方法参数泛型 =====");
+        for (Type param : paramTypes) {
+            System.out.println("参数类型: " + param);
+            if (param instanceof ParameterizedType) {
+                ParameterizedType ppt = (ParameterizedType) param;
+                System.out.println("   -> 实际类型参数: " + Arrays.toString(ppt.getActualTypeArguments()));
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/w8/Pair.java b/w8/Pair.java
new file mode 100644
index 0000000..49fd88a
--- /dev/null
+++ b/w8/Pair.java
@@ -0,0 +1,33 @@
+public class Pair<K, V> {
+    private final K key;
+    private final V value;
+
+    public Pair(K key, V value) {
+        this.key = key;
+        this.value = value;
+    }
+
+    public K getKey() {
+        return key;
+    }
+
+    public V getValue() {
+        return value;
+    }
+
+    public Pair<V, K> swap() {
+        return new Pair<>(this.value, this.key);
+    }
+
+    @Override
+    public String toString() {
+        return "Pair{" + key + " -> " + value + "}";
+    }
+
+    public static void main(String[] args) {
+        Pair<String, Integer> p1 = new Pair<>("age", 25);
+        System.out.println("原始: " + p1);
+        Pair<Integer, String> p2 = p1.swap();
+        System.out.println("交换后: " + p2);
+    }
+}
\ No newline at end of file