初始化

src/main/java/com/blog/service/UserService.java

@@ -0,0 +1,14 @@
+package com.blog.service;
+
+import com.blog.dto.UserLoginDto;
+import com.blog.dto.UserRegisterDto;
+import jakarta.validation.Valid;
+
+public interface UserService {
+
+     <T> T login(UserLoginDto user);
+
+     String register(UserRegisterDto userDto);
+
+     boolean exist(String username);
+}