修改了集合为空的判断

src/main/java/com/example/mybatisdemo/service/UserService.java

@@ -47,7 +47,7 @@ public class UserService implements IUserService{
     @Override
     public JsonResult selectUserByName(UserDTO userDTO) {
         List<User> users = iUserRepository.selectByName(userDTO.getName());
-        return (users!=null)?JsonResult.ok(users):JsonResult.fail();
+        return (users!=null && !users.isEmpty())?JsonResult.ok(users):JsonResult.fail();
     }