added all needed

src/main/java/mate/academy/mapstruct/config/MapperConfig.java

@@ -0,0 +1,13 @@
+package mate.academy.mapstruct.config;
+
+import org.mapstruct.InjectionStrategy;
+import org.mapstruct.NullValueCheckStrategy;
+
+@org.mapstruct.MapperConfig(
+        componentModel = "spring",
+        injectionStrategy = InjectionStrategy.CONSTRUCTOR,
+        nullValueCheckStrategy = NullValueCheckStrategy.ALWAYS,
+        implementationPackage = "<PACKAGE_NAME>.impl"
+)
+public class MapperConfig {
+}

src/main/java/mate/academy/mapstruct/mapper/GroupMapper.java

@@ -5,9 +5,19 @@
 import mate.academy.mapstruct.model.Group;
 import org.mapstruct.Mapper;
 
-@Mapper(config = MapperConfig.class)
+import java.util.Optional;
+
+@Mapper(config = MapperC)
 public interface GroupMapper {
     GroupDto toDto(Group group);
 
     Group toModel(CreateGroupRequestDto requestDto);
+
+    default Group getGroupById(Long id) {
+        return new Group(Optional.ofNullable(id).orElse(null));
+    }
+
+    default Long getIdFromGroup(Group group) {
+        return Optional.ofNullable(group.getId()).orElse(null);
+    }
 }

src/main/java/mate/academy/mapstruct/mapper/StudentMapper.java

@@ -3,41 +3,20 @@
 import mate.academy.mapstruct.dto.student.CreateStudentRequestDto;
 import mate.academy.mapstruct.dto.student.StudentDto;
 import mate.academy.mapstruct.dto.student.StudentWithoutSubjectsDto;
-import mate.academy.mapstruct.model.Group;
 import mate.academy.mapstruct.model.Student;
-import mate.academy.mapstruct.model.Subject;
 import org.mapstruct.Mapper;
 import org.mapstruct.Mapping;
 
-import java.util.List;
-import java.util.Optional;
-
-@Mapper(config = MapperConfig.class)
+@Mapper(config = MapperConfig.class, uses = {SubjectMapper.class, GroupMapper.class})
 public interface StudentMapper {
     @Mapping(target = "groupId", source = "group", qualifiedByName = "getIdFromGroup")
     @Mapping(target = "subjectIds", source = "subjects", qualifiedByName = "getIdsFromSubjects")
     StudentDto toDto(Student student);
 
-    @Mapping(target = "groupId", source = "group", qualifiedByName = "getId")
+    @Mapping(target = "groupId", source = "group", qualifiedByName = "getIdFromGroup")
     StudentWithoutSubjectsDto toEmployeeWithoutSubjectsDto(Student student);
 
     @Mapping(target = "group", source = "groupId", qualifiedByName = "getGroupById")
     @Mapping(target = "subjects", source = "subjects", qualifiedByName = "getSubjectsByIds")
     Student toModel(CreateStudentRequestDto requestDto);
-
-    default Long getIdFromGroup(Group group) {
-        return Optional.ofNullable(group.getId()).orElse(null);
-    }
-
-    default List<Long> getIdsFromSubjects(List<Subject> subjects) {
-        return subjects.stream().map(s -> s.getId()).toList();
-    }
-
-    default Group getGroupById(Long id) {
-        return Optional.
-    }
-
-    default List<Subject> getSubjectsByIds(List<Long> longList) {
-        return longList.stream().map(Subject::new).toList();
-    }
 }

src/main/java/mate/academy/mapstruct/mapper/SubjectMapper.java

@@ -6,9 +6,19 @@
 import mate.academy.mapstruct.model.Subject;
 import org.mapstruct.Mapper;
 
+import java.util.List;
+
 @Mapper(config = MapperConfig.class)
 public interface SubjectMapper {
     SubjectDto toDto(Subject subject);
 
     Subject toModel(CreateSubjectRequestDto requestDto);
+
+    default List<Subject> getSubjectsByIds(List<Long> longList) {
+        return longList.stream().map(Subject::new).toList();
+    }
+
+    default List<Long> getIdsFromSubjects(List<Subject> subjects) {
+        return subjects.stream().map(s -> s.getId()).toList();
+    }
 }