Начало: Department

build.gradle

@@ -7,6 +7,18 @@ plugins {
 group = 'com.example'
 version = '0.0.1-SNAPSHOT'
 
+defaultTasks 'bootRun'
+
+jar {
+    enabled = false
+}
+
+bootJar {
+    archiveFileName = String.format('%s-%s.jar', rootProject.name, version)
+}
+
+assert System.properties['java.specification.version'] == '17' || '21'
+
 java {
 	sourceCompatibility = '17'
 }
@@ -17,9 +29,13 @@ repositories {
 
 dependencies {
 	implementation 'org.springframework.boot:spring-boot-starter-web'
+	implementation 'org.springframework.boot:spring-boot-starter-validation'
 	implementation 'org.springdoc:springdoc-openapi-starter-webmvc-ui:2.3.0'
 	implementation 'org.modelmapper:modelmapper:3.2.0'
 
+	implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
+	implementation 'com.h2database:h2:2.2.224'
+
 	testImplementation 'org.springframework.boot:spring-boot-starter-test'
 }
 

src/main/java/com/example/demo/core/configuration/Constants.java

@@ -1,6 +1,8 @@
 package com.example.demo.core.configuration;
 
 public class Constants {
+    public static final String SEQUENCE_NAME = "hibernate_sequence";
+
     public static final String API_URL = "/api/1.0";
 
     private Constants() {

src/main/java/com/example/demo/core/error/NotFoundException.java

@@ -1,7 +1,7 @@
 package com.example.demo.core.error;
 
 public class NotFoundException extends RuntimeException {
-    public NotFoundException(Long id) {
-        super(String.format("Entity with id [%s] is not found or not exists", id));
+    public <T> NotFoundException(Class<T> clazz, Long id) {
+        super(String.format("%s with id [%s] is not found or not exists", clazz.getSimpleName(), id));
     }
 }

src/main/java/com/example/demo/core/model/BaseEntity.java

@@ -1,15 +1,23 @@
 package com.example.demo.core.model;
 
+import com.example.demo.core.configuration.Constants;
+
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.MappedSuperclass;
+import jakarta.persistence.SequenceGenerator;
+
+@MappedSuperclass
 public abstract class BaseEntity {
+    @Id
+    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = Constants.SEQUENCE_NAME)
+    @SequenceGenerator(name = Constants.SEQUENCE_NAME, sequenceName = Constants.SEQUENCE_NAME, allocationSize = 1)
     protected Long id;
 
     protected BaseEntity() {
     }
 
-    protected BaseEntity(Long id) {
-        this.id = id;
-    }
-
     public Long getId() {
         return id;
     }

src/main/java/com/example/demo/core/repository/CommonRepository.java

@@ -1,17 +0,0 @@
-package com.example.demo.core.repository;
-
-import java.util.List;
-
-public interface CommonRepository<E, T> {
-    List<E> getAll();
-
-    E get(T id);
-
-    E create(E entity);
-
-    E update(E entity);
-
-    E delete(E entity);
-
-    void deleteAll();
-}

src/main/java/com/example/demo/core/repository/MapRepository.java

@@ -1,57 +0,0 @@
-package com.example.demo.core.repository;
-
-import java.util.List;
-import java.util.Map;
-import java.util.TreeMap;
-
-import com.example.demo.core.model.BaseEntity;
-
-public abstract class MapRepository<E extends BaseEntity> implements CommonRepository<E, Long> {
-    private final Map<Long, E> entities = new TreeMap<>();
-    private Long lastId = 0L;
-
-    protected MapRepository() {
-    }
-
-    @Override
-    public List<E> getAll() {
-        return entities.values().stream().toList();
-    }
-
-    @Override
-    public E get(Long id) {
-        return entities.get(id);
-    }
-
-    @Override
-    public E create(E entity) {
-        lastId++;
-        entity.setId(lastId);
-        entities.put(lastId, entity);
-        return entity;
-    }
-
-    @Override
-    public E update(E entity) {
-        if (get(entity.getId()) == null) {
-            return null;
-        }
-        entities.put(entity.getId(), entity);
-        return entity;
-    }
-
-    @Override
-    public E delete(E entity) {
-        if (get(entity.getId()) == null) {
-            return null;
-        }
-        entities.remove(entity.getId());
-        return entity;
-    }
-
-    @Override
-    public void deleteAll() {
-        lastId = 0L;
-        entities.clear();
-    }
-}

src/main/java/com/example/demo/department/model/DepartmentEntity.java

@@ -4,15 +4,20 @@ import java.util.Objects;
 
 import com.example.demo.core.model.BaseEntity;
 
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Table;
+
+@Entity
+@Table(name = "departments")
 public class DepartmentEntity extends BaseEntity {
+    @Column(nullable = false, unique = true, length = 80)
     private String name;
 
     public DepartmentEntity() {
-        super();
     }
 
     public DepartmentEntity(Long id, String name) {
-        super(id);
         this.name = name;
     }
 

src/main/java/com/example/demo/department/repository/DepartmentRepository.java

@@ -1,10 +1,11 @@
 package com.example.demo.department.repository;
 
-import org.springframework.stereotype.Repository;
+import java.util.Optional;
+
+import org.springframework.data.repository.CrudRepository;
 
-import com.example.demo.core.repository.MapRepository;
 import com.example.demo.department.model.DepartmentEntity;
 
-@Repository
-public class DepartmentRepository extends MapRepository<DepartmentEntity> {
+public interface DepartmentRepository extends CrudRepository<DepartmentEntity, Long> {
+    Optional<DepartmentEntity> findByNameIgnoreCase(String name);
 }

src/main/java/com/example/demo/department/service/DepartmentService.java

@@ -1,9 +1,10 @@
 package com.example.demo.department.service;
 
 import java.util.List;
-import java.util.Optional;
+import java.util.stream.StreamSupport;
 
 import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
 
 import com.example.demo.core.error.NotFoundException;
 import com.example.demo.department.model.DepartmentEntity;
@@ -17,27 +18,45 @@ public class DepartmentService {
         this.repository = repository;
     }
 
+    private void checkName(String name) {
+        if (repository.findByNameIgnoreCase(name).isPresent()) {
+            throw new IllegalArgumentException(
+                    String.format("Type with name %s is already exists", name));
+        }
+    }
+
+    @Transactional(readOnly = true)
     public List<DepartmentEntity> getAll() {
-        return repository.getAll();
+        return StreamSupport.stream(repository.findAll().spliterator(), false).toList();
     }
 
+    @Transactional(readOnly = true)
     public DepartmentEntity get(Long id) {
-        return Optional.ofNullable(repository.get(id))
-                .orElseThrow(() -> new NotFoundException(id));
+        return repository.findById(id)
+                .orElseThrow(() -> new NotFoundException(DepartmentEntity.class, id));
     }
 
+    @Transactional
     public DepartmentEntity create(DepartmentEntity entity) {
-        return repository.create(entity);
+        if (entity == null) {
+            throw new IllegalArgumentException("Entity is null");
+        }
+        checkName(entity.getName());
+        return repository.save(entity);
     }
 
+    @Transactional
     public DepartmentEntity update(Long id, DepartmentEntity entity) {
         final DepartmentEntity existsEntity = get(id);
+        checkName(entity.getName());
         existsEntity.setName(entity.getName());
-        return repository.update(existsEntity);
+        return repository.save(existsEntity);
     }
 
+    @Transactional
     public DepartmentEntity delete(Long id) {
         final DepartmentEntity existsEntity = get(id);
-        return repository.delete(existsEntity);
+        repository.delete(existsEntity);
+        return existsEntity;
     }
 }