段階2です

src/main/java/com/example/rhizome/app/domain/service/DeleteDepartment.java

@@ -0,0 +1,5 @@
+package com.example.rhizome.app.domain.service;
+
+public interface DeleteDepartment {
+	void deleteDepartment(Integer idDepartment);
+}

src/main/java/com/example/rhizome/app/domain/service/impl/DeleteDepartmentImpl.java

@@ -0,0 +1,32 @@
+package com.example.rhizome.app.domain.service.impl;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import com.example.rhizome.app.domain.service.DeleteDepartment;
+import com.example.rhizome.app.infra.repository.DepartmentRepository;
+
+/**
+ * Department レコード削除関連の機能を持つサービス
+ */
+@Service
+@Transactional
+public class DeleteDepartmentImpl implements DeleteDepartment {
+
+	DepartmentRepository departmentRepository;
+
+	@Autowired
+	public DeleteDepartmentImpl(DepartmentRepository departmentRepository) {
+		this.departmentRepository = departmentRepository;
+	}
+
+	/**
+	 * idDepartment を元に department データを削除
+	 *
+	 * @param idDepartment 削除対象のidDepartmnet
+	 */
+	public void deleteDepartment(Integer idDepartment) {
+		departmentRepository.deleteById(idDepartment);
+	}
+}

src/main/java/com/example/rhizome/app/presentation/controller/DeleteDepartmentController.java

@@ -0,0 +1,120 @@
+package com.example.rhizome.app.presentation.controller;
+
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import javax.servlet.http.HttpSession;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Controller;
+import org.springframework.ui.Model;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RequestParam;
+
+import com.example.rhizome.app.domain.model.SearchConditionDepartment;
+import com.example.rhizome.app.domain.service.DeleteDepartment;
+import com.example.rhizome.app.domain.service.SearchDepartment;
+import com.example.rhizome.app.domain.service.SearchEmployee;
+import com.example.rhizome.app.presentation.controller.pageproperty.PageReturnAttributeKeyword;
+import com.example.rhizome.app.presentation.controller.pageproperty.TransitionTargetPageNameKeyword;
+import com.example.rhizome.app.presentation.form.DepartmentForm;
+import com.example.rhizome.app.presentation.form.MessageForm;
+
+/**
+ * 削除処理のコントロータ
+ */
+@Controller
+public class DeleteDepartmentController {
+	// ログ出力用インスタンス
+	private final static Logger LOGGER = Logger.getLogger(DeleteEmployeeController.class.getName());
+
+	// エラーメッセージ用の定数フィールド
+	private final static String SEVERE_ERROR_MESSAGE = "エラーが発生しました！";
+
+	HttpSession httpSession;
+	DeleteDepartment deleteDepartment;
+	SearchDepartment searchDepartment;
+	SearchEmployee searchEmployee; // 所属社員の確認に使う（既存）
+
+	@Autowired
+	public DeleteDepartmentController(DeleteDepartment deleteDepartment, SearchDepartment searchDepartment,
+			HttpSession httpSession, SearchEmployee searchEmployee) {
+		this.httpSession = httpSession;
+		this.deleteDepartment = deleteDepartment;
+		this.searchDepartment = searchDepartment;
+		this.searchEmployee = searchEmployee;
+	}
+
+	/**
+	 * 削除処理のコントローラ
+	 *
+	 * @param idDepartment 削除対象のdepartmentId
+	 * @param model      ビューにデータを渡すためのコンテナ
+	 * @return 遷移先の画面
+	 */
+
+	@RequestMapping(value = TransitionTargetPageNameKeyword.DELETE_DEPARTMENT, method = RequestMethod.POST)
+	public String deleteDepartment(@RequestParam(value = "idDepartment", required = false) Integer idDepartment,
+			Model model) {
+
+		final String UNKNOWN_ID = "削除対象のIDが不明です。";
+
+		try {
+			// 部署一覧を取得し、画面に返す用のクラスに詰め替える
+			// 作成した部署一覧をセット
+			model.addAttribute(
+					PageReturnAttributeKeyword.DEPARTMENT_FORM_LIST,
+					DepartmentForm.convertFrom(searchDepartment.selectAll()));
+
+			if (idDepartment == null
+					|| searchDepartment.searchBy(new SearchConditionDepartment(idDepartment, null)) == null) {
+				model.addAttribute(PageReturnAttributeKeyword.MESSAGE_ERROR, new MessageForm(UNKNOWN_ID));
+			}
+
+			// 削除処理実施
+			deleteExec(model, idDepartment);
+
+			// 検索画面に遷移
+			return "forward:" + TransitionTargetPageNameKeyword.SELECT_DEPARTMENT_FORM_EMPTY;
+
+		} catch (Exception e) {
+			// ログイン情報の破棄
+			httpSession.invalidate();
+			e.printStackTrace();
+			// エラーログ出力
+			LOGGER.log(Level.SEVERE, SEVERE_ERROR_MESSAGE, e);
+			// エラー画面遷移
+			return TransitionTargetPageNameKeyword.ERROR_HTML;
+		}
+	}
+
+	/**
+	 * 削除処理実施
+	 *
+	 * @param model      ビューにデータを渡すためのコンテナ
+	 * @param idEmployee 削除対象のDepartmentId
+	 */
+	private void deleteExec(Model model, Integer idDepartment) {
+
+		final String DELETE_DPARTMENT_TARGET_ID_CAN_NOT_DELETE = "1名以上が所属している部署は削除出来ません。";
+		final String DELETE_COMPLETE = "削除しました。";
+
+		// 削除対象部署が1名以上所属しているかチェック
+		if (!searchEmployee.searchEmployeeByIdDepartment(idDepartment).isEmpty()) {
+			// 削除対象だった場合
+			// エラーメッセージをセット
+			model.addAttribute(PageReturnAttributeKeyword.MESSAGE_ERROR,
+					new MessageForm(DELETE_DPARTMENT_TARGET_ID_CAN_NOT_DELETE));
+			// 検索画面に遷移
+			return;
+		}
+
+		// 削除を実施
+		deleteDepartment.deleteDepartment(idDepartment);
+
+		// 削除完了したメッセージをセット
+		model.addAttribute(PageReturnAttributeKeyword.MESSAGE_INFO, new MessageForm(DELETE_COMPLETE));
+
+	}
+}

src/main/java/com/example/rhizome/app/presentation/controller/DeleteEmployeeController.java

@@ -1,6 +1,21 @@
 package com.example.rhizome.app.presentation.controller;
 
 
+import static com.example.rhizome.app.presentation.controller.pageproperty.TransitionTargetPageNameKeyword.*;
+
+import java.util.Objects;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import javax.servlet.http.HttpSession;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Controller;
+import org.springframework.ui.Model;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RequestParam;
+
 import com.example.rhizome.aop.aspect.PermissionCheck;
 import com.example.rhizome.aop.aspect.SessionCheck;
 import com.example.rhizome.app.domain.model.LoginUser;
@@ -12,22 +27,9 @@ import com.example.rhizome.app.presentation.controller.pageproperty.TransitionTa
 import com.example.rhizome.app.presentation.form.DepartmentForm;
 import com.example.rhizome.app.presentation.form.LoginUserForm;
 import com.example.rhizome.app.presentation.form.MessageForm;
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.stereotype.Controller;
-import org.springframework.ui.Model;
-import org.springframework.web.bind.annotation.RequestMapping;
-import org.springframework.web.bind.annotation.RequestMethod;
-import org.springframework.web.bind.annotation.RequestParam;
-
-import javax.servlet.http.HttpSession;
-import java.util.Objects;
-import java.util.logging.Level;
-import java.util.logging.Logger;
-
-import static com.example.rhizome.app.presentation.controller.pageproperty.TransitionTargetPageNameKeyword.DELETE_EMPLOYEE;
 
 /**
- * 削除処理のコントロータ
+ * 削除処理のコントローラ
  */
 @Controller
 public class DeleteEmployeeController {

src/main/java/com/example/rhizome/app/presentation/controller/SelectDepartmentController.java

@@ -106,10 +106,10 @@ public class SelectDepartmentController {
 				DepartmentForm.convertFrom(searchDepartment.selectAll()));
 
 		// 検索条件を元に検索を実施
-//		model.addAttribute(PageReturnAttributeKeyword.DEPARTMENT_FORM_LIST,
+		//		model.addAttribute(PageReturnAttributeKeyword.DEPARTMENT_FORM_LIST,
-//				DepartmentForm.convertFrom(
+		//				DepartmentForm.convertFrom(
-//						searchDepartment.searchBy(
+		//						searchDepartment.searchBy(
-//								SearchConditionDepartmentForm.convertTo(searchConditionDepartmentForm()))));
+		//								SearchConditionDepartmentForm.convertTo(searchConditionDepartmentForm()))));
 
 		//部分一致検索
 		model.addAttribute(PageReturnAttributeKeyword.DEPARTMENT_FORM_LIST,

src/main/java/com/example/rhizome/app/presentation/controller/pageproperty/TransitionTargetPageNameKeyword.java

@@ -56,6 +56,7 @@ public class TransitionTargetPageNameKeyword {
 	public static final String SELECT_DEPARTMENT = "/selectDepartment";
 	public static final String SELECT_DEPARTMENT_FORM_EMPTY = "/selectAll2";
 	public static final String INSERT_DEPARTMENT_INPUT = "/insertDepartmentInput";
+	public static final String DELETE_DEPARTMENT = "/deleteDepartment";
 
 	/**
 	 * 管理者向けのページリストを返す

src/main/resources/templates/selectDepartment.html

@@ -57,6 +57,7 @@
 			alert([[${messageInfo.message}]]);
 		</script>
 	</th:block>
+
 	<div class="header-spacing"></div>
 	<th:block th:if="${departmentFormList != null and departmentFormList.size() > 0}">
 		<!-- 検索結果が1件以上ある場合 -->
@@ -93,6 +94,7 @@
 		<!-- 検索結果が0件の場合 -->
 		検索結果はありません。
 	</th:block>
+
 </body>
 <script type="text/javascript">