add dto, refactor names, update controllers

src/main/java/com/faf223/expensetrackerfaf/dto/mappers/UserMapper.java

@@ -0,0 +1,28 @@
+package com.faf223.expensetrackerfaf.dto.mappers;
+
+import com.faf223.expensetrackerfaf.dto.UserCreationDTO;
+import com.faf223.expensetrackerfaf.dto.UserDTO;
+import com.faf223.expensetrackerfaf.model.User;
+import com.faf223.expensetrackerfaf.service.UserService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+@Component
+public class UserMapper {
+
+    private final UserService userService;
+
+    @Autowired
+    public UserMapper(UserService userService) {
+        this.userService = userService;
+    }
+
+    public UserDTO toDto(User user) {
+        return new UserDTO(user.getUuid(), user.getName(), user.getSurname(), user.getUsername());
+    }
+
+    public User toUser(UserCreationDTO userDTO) {
+        return userService.getUserById(userDTO.getUuid());
+    }
+
+}