diff --git a/pom.xml b/pom.xml
index 05a8106..1126b61 100644
--- a/pom.xml
+++ b/pom.xml
@@ -13,5 +13,13 @@
         <maven.compiler.target>21</maven.compiler.target>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.13.2</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
 
 </project>
\ No newline at end of file
diff --git a/src/main/java/cn/zhangdeman/CustomExceptionEnum.java b/src/main/java/cn/zhangdeman/CustomExceptionEnum.java
deleted file mode 100644
index f69bb94..0000000
--- a/src/main/java/cn/zhangdeman/CustomExceptionEnum.java
+++ /dev/null
@@ -1,12 +0,0 @@
-package cn.zhangdeman;
-
-// 自定义异常的枚举值
-public enum CustomExceptionEnum {
-    ;
-    private final Object code; // 异常状态码
-    private final String message; // 异常信息
-    CustomExceptionEnum(Object code, String message) {
-        this.code = code;
-        this.message = message;
-    }
-}
diff --git a/src/main/java/cn/zhangdeman/HashMapCache.java b/src/main/java/cn/zhangdeman/HashMapCache.java
new file mode 100644
index 0000000..bb0b081
--- /dev/null
+++ b/src/main/java/cn/zhangdeman/HashMapCache.java
@@ -0,0 +1,32 @@
+package cn.zhangdeman;
+
+import java.util.HashMap;
+import java.util.Map;
+
+// 基于hashmap实现的内存缓存
+// 因为就是服务启动时初始化一次, 无需考虑多线程并发安全问题
+public class HashMapCache {
+    // 单例: 饿汉模式
+    private static final HashMapCache hashMapCache = new HashMapCache();
+    private final Map<Object, String> cache = new HashMap<>();
+    //将构造器设置为private禁止通过new进行实例化
+    private HashMapCache() {
+
+    }
+    public static HashMapCache getHashMapCache() {
+        return hashMapCache;
+    }
+    // 读取
+    public String getCodeMessage(Object code) {
+        if (!cache.containsKey(code)) {
+            // 不包含指定code
+            return code.toString();
+        }
+        return cache.get(code);
+    }
+
+    // 添加
+    public void put(Object code, String message) {
+        cache.put(code, message);
+    }
+}
diff --git a/src/test/java/cn/zhangdeman/HashMapCacheTest.java b/src/test/java/cn/zhangdeman/HashMapCacheTest.java
new file mode 100644
index 0000000..5b1f273
--- /dev/null
+++ b/src/test/java/cn/zhangdeman/HashMapCacheTest.java
@@ -0,0 +1,14 @@
+package cn.zhangdeman;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class HashMapCacheTest {
+    @Test
+    public void runHashMapCache() {
+        HashMapCache.getHashMapCache().put(200, "OK");
+        Assert.assertEquals("OK", HashMapCache.getHashMapCache().getCodeMessage(200));
+    }
+}
\ No newline at end of file