diff --git a/w8/Cache.java b/w8/Cache.java
new file mode 100644
index 0000000..9136e2e
--- /dev/null
+++ b/w8/Cache.java
@@ -0,0 +1,20 @@
+import java.util.HashMap;
+ import java.util.Map;
+public class Cache<K, V> {
+     private final Map<K, V> cache;
+     public Cache() {
+         cache = new HashMap<>();
+     }
+     public synchronized void put(K key, V value) {
+         cache.put(key, value);
+     }
+     public synchronized V get(K key) {
+         return cache.get(key);
+     }
+     public synchronized boolean hasKey(K key) {
+         return cache.containsKey(key);
+     }
+     public synchronized void remove(K key) {
+         cache.remove(key);
+     }
+ }
\ No newline at end of file
diff --git a/w8/Main.java b/w8/Main.java
new file mode 100644
index 0000000..44fba21
--- /dev/null
+++ b/w8/Main.java
@@ -0,0 +1,9 @@
+public class Main {
+    public void main(){
+        Pair pair=new Pair("鞋子",7);
+        Pair pair2=pair.swap(pair);
+        Object a=pair2.getkey();
+        Object b=pair2.getvalue();
+        System.out.println("pair2的key是 "+a+" value 是 "+b);
+    }
+}
diff --git a/w8/Pair.java b/w8/Pair.java
new file mode 100644
index 0000000..ac7c89b
--- /dev/null
+++ b/w8/Pair.java
@@ -0,0 +1,18 @@
+public class Pair<K,V>{
+    K key;
+    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 static Pair swap (Pair pair){
+        return new Pair(pair.getvalue(),pair.getkey());
+
+    }
+}
\ No newline at end of file