1段階目です。

src/com/rhizome/example/dao/EmployeeDAO.java

@@ -13,7 +13,6 @@ import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.List;
 
-import com.rhizome.example.dto.EmployeeDTO;
 import com.rhizome.example.util.DbUtil;
 
 public class EmployeeDAO {
@@ -49,8 +48,8 @@ public class EmployeeDAO {
 	 * @throws SQLException
 	 * @throws ClassNotFoundException
 	 */
-	public List<EmployeeDTO> selectAll() throws SQLException, ClassNotFoundException {
-		List<EmployeeDTO> rtnList = new ArrayList<>();
+	public List<String> selectAll() throws SQLException, ClassNotFoundException {
+		List<String> rtnList = new ArrayList<>();
 		StringBuilder sql = new StringBuilder();
 		sql.append(" SELECT ");
 		sql.append("    " + "*");
@@ -61,10 +60,7 @@ public class EmployeeDAO {
 			this.stmt = con.prepareStatement(sql.toString());
 			rs = stmt.executeQuery();
 			while (rs.next()) {
-				EmployeeDTO dto = new EmployeeDTO(rs.getInt(ID_EMPLOYEE), rs.getString(NM_EMPLOYEE),
-						rs.getString(KN_EMPLOYEE), rs.getString(MAIL_ADDRESS), rs.getString(PASSWORD),
-						rs.getInt(ID_DEPARTMENT));
-				rtnList.add(dto);
+				rtnList.add(rs.getString(NM_EMPLOYEE));
 			}
 		} finally {
 			DbUtil.closeStatement(this.stmt);
@@ -72,159 +68,4 @@ public class EmployeeDAO {
 		return rtnList;
 	}
 
-	/**
-	 * 社員テーブルから社員IDに合致する情報を取得する
-	 * @param id
-	 * 			検索する社員ID
-	 * @return 検索結果
-	 * @throws SQLException
-	 * @throws ClassNotFoundException
-	 * @throws NumberFormatException
-	 */
-	public List<EmployeeDTO> selectById​(int id)
-			throws SQLException, ClassNotFoundException, NumberFormatException {
-		List<EmployeeDTO> rtnList = new ArrayList<>();
-		StringBuilder sql = new StringBuilder();
-		sql.append(" SELECT ");
-		sql.append("    " + "*");
-		sql.append(" FROM ");
-		sql.append("    " + TBL_NAME);
-		sql.append(" WHERE ");
-		sql.append("    " + ID_EMPLOYEE);
-		sql.append(" = ");
-		sql.append("    " + id);
-		try {
-
-			this.stmt = con.prepareStatement(sql.toString());
-			rs = stmt.executeQuery();
-			while (rs.next()) {
-
-				EmployeeDTO dto = new EmployeeDTO(rs.getInt(ID_EMPLOYEE), rs.getString(NM_EMPLOYEE),
-						rs.getString(KN_EMPLOYEE), rs.getString(MAIL_ADDRESS), rs.getString(PASSWORD),
-						rs.getInt(ID_DEPARTMENT));
-				rtnList.add(dto);
-
-			}
-		} finally {
-			DbUtil.closeStatement(this.stmt);
-		}
-		if (rtnList.size() == 0) {
-			System.out.println("入力された値で情報がみつかりませんでした");
-		}
-		return rtnList;
-	}
-
-	/**
-	 * 社員テーブルの社員IDに合致する情報を削除する
-	 *
-	 * @param id
-	 *			削除ID
-	 * @throws ClassNotFoundException
-	 * @throws SQLException
-	 * @throws NumberFormatException
-	 */
-	public void empDelete​(int id)
-			throws ClassNotFoundException, SQLException, NumberFormatException {
-		StringBuilder sql = new StringBuilder();
-		sql.append(" DELETE ");
-		sql.append(" FROM ");
-		sql.append("    " + TBL_NAME);
-		sql.append(" WHERE ");
-		sql.append("    " + ID_EMPLOYEE);
-		sql.append(" = ");
-		sql.append("    " + id);
-
-		try {
-			this.stmt = con.prepareStatement(sql.toString());
-			stmt.executeUpdate();
-			System.out.println("削除が完了しました");
-		} finally {
-			DbUtil.closeStatement(this.stmt);
-		}
-
-	}
-
-	/**
-	 * 社員テーブルに指定された情報を新規登録する
-	 *
-	 * @param name - 社員名
-	 * @param kana - 社員名カナ
-	 * @param mail - メールアドレス
-	 * @param pass - パスワード
-	 * @param depId - 部署ID
-	 * @throws NumberFormatException
-	 * @throws SQLException
-	 * @throws ClassNotFoundException
-	 */
-	public void empInsert​(String name, String kana, String mail, String pass, int depId)
-			throws NumberFormatException, SQLException, ClassNotFoundException {
-		StringBuilder sql = new StringBuilder();
-		sql.append(" INSERT ");
-		sql.append(" INTO ");
-		sql.append("    " + TBL_NAME);
-		sql.append(" ( " + NM_EMPLOYEE);
-		sql.append(" , " + KN_EMPLOYEE);
-		sql.append(" , " + MAIL_ADDRESS);
-		sql.append(" , " + PASSWORD);
-		sql.append(" , " + ID_DEPARTMENT + " ) ");
-		sql.append(" VALUES ");
-		sql.append(" ( '" + name);
-		sql.append("' , '" + kana);
-		sql.append("' , '" + mail);
-		sql.append("' , '" + pass);
-		sql.append("' , " + depId + " ) ");
-
-		try {
-			this.stmt = con.prepareStatement(sql.toString());
-			stmt.executeUpdate();
-			System.out.println("登録が完了しました");
-		} finally {
-			DbUtil.closeStatement(this.stmt);
-		}
-	}
-
-	/**
-	 * 社員テーブルの社員IDに合致する情報を更新する
-	 *
-	 * @param id - 社員ID
-	 * @param name - 社員名
-	 * @param kana - 社員名カナ
-	 * @param mail - メールアドレス
-	 * @param pass - パスワード
-	 * @param depId - 部署ID
-	 * @throws ClassNotFoundException
-	 * @throws SQLException
-	 * @throws NumberFormatException
-	
-	 */
-	public void empUpdate​(int id, String name, String kana, String mail, String pass, int depId)
-			throws ClassNotFoundException, SQLException, NumberFormatException {
-		StringBuilder sql = new StringBuilder();
-		sql.append(" UPDATE ");
-		sql.append("    " + TBL_NAME);
-		sql.append(" SET ");
-		sql.append("    " + NM_EMPLOYEE);
-		sql.append(" = '" + name + " ' ");
-		sql.append(" , " + KN_EMPLOYEE);
-		sql.append(" = '" + kana + " ' ");
-		sql.append(" , " + MAIL_ADDRESS);
-		sql.append(" = '" + mail + " ' ");
-		sql.append(" , " + PASSWORD);
-		sql.append(" = '" + pass + " ' ");
-		sql.append(" , " + ID_DEPARTMENT);
-		sql.append(" = " + depId);
-		sql.append(" WHERE ");
-		sql.append("    " + ID_EMPLOYEE);
-		sql.append(" = ");
-		sql.append("    " + id);
-
-		try {
-			this.stmt = con.prepareStatement(sql.toString());
-			stmt.executeUpdate();
-			System.out.println("更新が完了しました");
-		} finally {
-			DbUtil.closeStatement(this.stmt);
-		}
-
-	}
 }

src/com/rhizome/example/dto/EmployeeDTO.java

@@ -1,79 +0,0 @@
-package com.rhizome.example.dto;
-
-public class EmployeeDTO {
-	private int ID_EMPLOYEE;
-	private String NM_EMPLOYEE;
-	private String KN_EMPLOYEE;
-	private String MAIL_ADDRESS;
-	private String PASSWORD;
-	private int ID_DEPARTMENT;
-
-	public EmployeeDTO() {
-
-	}
-
-	public EmployeeDTO(int ID_EMPLOYEE, String NM_EMPLOYEE, String KN_EMPLOYEE, String MAIL_ADDRESS, String PASSWORD,
-			int ID_DEPARTMENT) {
-		setID_EMPLOYEE(ID_EMPLOYEE);
-		setNM_EMPLOYEE(NM_EMPLOYEE);
-		setKN_EMPLOYEE(KN_EMPLOYEE);
-		setMAIL_ADDRESS(MAIL_ADDRESS);
-		setPASSWORD(PASSWORD);
-		setID_DEPARTMENT(ID_DEPARTMENT);
-	}
-
-	public int getID_EMPLOYEE() {
-		return ID_EMPLOYEE;
-	}
-
-	public void setID_EMPLOYEE(int iD_EMPLOYEE) {
-		ID_EMPLOYEE = iD_EMPLOYEE;
-	}
-
-	public String getNM_EMPLOYEE() {
-		return NM_EMPLOYEE;
-	}
-
-	public void setNM_EMPLOYEE(String nM_EMPLOYEE) {
-		NM_EMPLOYEE = nM_EMPLOYEE;
-	}
-
-	public String getKN_EMPLOYEE() {
-		return KN_EMPLOYEE;
-	}
-
-	public void setKN_EMPLOYEE(String kN_EMPLOYEE) {
-		KN_EMPLOYEE = kN_EMPLOYEE;
-	}
-
-	public String getMAIL_ADDRESS() {
-		return MAIL_ADDRESS;
-	}
-
-	public void setMAIL_ADDRESS(String mAIL_ADDRESS) {
-		MAIL_ADDRESS = mAIL_ADDRESS;
-	}
-
-	public String getPASSWORD() {
-		return PASSWORD;
-	}
-
-	public void setPASSWORD(String pASSWORD) {
-		PASSWORD = pASSWORD;
-	}
-
-	public int getID_DEPARTMENT() {
-		return ID_DEPARTMENT;
-	}
-
-	public void setID_DEPARTMENT(int iD_DEPARTMENT) {
-		ID_DEPARTMENT = iD_DEPARTMENT;
-	}
-
-	public void showInfo() {
-		System.out.println(ID_EMPLOYEE + "\t" + NM_EMPLOYEE +
-				"\t" + KN_EMPLOYEE + "\t" + MAIL_ADDRESS +
-				"\t" + PASSWORD + "\t" + ID_DEPARTMENT);
-	}
-
-}

src/com/rhizome/example/main/Main.java

@@ -7,7 +7,6 @@ import java.util.List;
 import java.util.Scanner;
 
 import com.rhizome.example.dao.EmployeeDAO;
-import com.rhizome.example.dto.EmployeeDTO;
 import com.rhizome.example.util.DbUtil;
 
 /**
@@ -54,13 +53,10 @@ public class Main {
 			empSelect();
 			break;
 		case "2":
-			empInsert​();
 			break;
 		case "3":
-			empUpdate​();
 			break;
 		case "4":
-			empDelete​();
 			break;
 		case "9":
 			return;
@@ -73,93 +69,6 @@ public class Main {
 		}
 	}
 
-	/**
-	 * 社員テーブルの社員IDに合致する情報を更新する
-	 *
-	 * @throws ClassNotFoundException
-	 * @throws SQLException
-	 * @throws NumberFormatException
-	 */
-	public static void empUpdate​()
-			throws ClassNotFoundException, SQLException, NumberFormatException {
-		Connection con = DbUtil.getConnection();
-		EmployeeDAO empDao = new EmployeeDAO(con);
-		int id = Integer.parseInt(inputCheck("ID", true));
-
-		if (empDao.selectById​(id).size() == 0) {
-			return;
-		}
-		String name = inputCheck("社員名", false);
-		String kana = inputCheck("フリガナ", false);
-		String mail = inputCheck("メールアドレス", false);
-		String pass = inputCheck("パスワード", false);
-		int depId = Integer.parseInt(inputCheck("部署ID", true));
-
-		try {
-			empDao.empUpdate​(id, name, kana, mail, pass, depId);
-		} finally {
-			DbUtil.closeConnection(empDao.con);
-		}
-	}
-
-	/**
-	 * 社員テーブルに指定された情報を新規登録する
-	 * @throws NumberFormatException
-	 * @throws SQLException
-	 * @throws ClassNotFoundException
-	 */
-	public static void empInsert​()
-			throws NumberFormatException, SQLException, ClassNotFoundException {
-		Connection con = DbUtil.getConnection();
-		EmployeeDAO empDao = new EmployeeDAO(con);
-
-		String name = inputCheck("社員名", false);
-		String kana = inputCheck("フリガナ", false);
-		String mail = inputCheck("メールアドレス", false);
-		String pass = inputCheck("パスワード", false);
-		int depId = Integer.parseInt(inputCheck("部署ID", true));
-
-		try {
-			empDao.empInsert​(name, kana, mail, pass, depId);
-		} finally {
-			DbUtil.closeConnection(empDao.con);
-		}
-
-	}
-
-	/**
-	 * 社員テーブルの社員IDに合致する情報を削除する
-	 *
-	 * @throws ClassNotFoundException
-	 * @throws SQLException
-	 */
-	public static void empDelete​()
-			throws ClassNotFoundException, SQLException, NumberFormatException {
-		List<EmployeeDTO> rtnList = new ArrayList<>();
-		Connection con = DbUtil.getConnection();
-		EmployeeDAO empDao = new EmployeeDAO(con);
-		int id = Integer.parseInt(inputCheck("ID", true));
-		rtnList = empDao.selectById​(id);
-		if (rtnList.size() == 0) {
-			return;
-		}
-
-		System.out.println("指定されたIDの情報を削除します？ Y/y\r\n"
-				+ "（Y/y以外の入力であればキャンセル）");
-
-		String str = inputCheck(false);
-
-		if (!str.equalsIgnoreCase("y")) {
-			System.out.println("キャンセルしました");
-			return;
-		}
-		try {
-			empDao.empDelete​(id);
-		} finally {
-			DbUtil.closeConnection(empDao.con);
-		}
-	}
-
 	/**
 	 * 社員テーブルから情報を検索する
 	 *
@@ -167,7 +76,7 @@ public class Main {
 	 * @throws SQLException
 	 */
 	public static void empSelect() throws ClassNotFoundException, SQLException {
-		List<EmployeeDTO> empList = new ArrayList<>();
+		List<String> empList = new ArrayList<>();
 		Connection con = DbUtil.getConnection();
 		EmployeeDAO empDao = new EmployeeDAO(con);
 		System.out.println("1:全検索 2:条件検索 それ以外:戻る");
@@ -177,14 +86,11 @@ public class Main {
 			case "1":
 				empList = empDao.selectAll();
 				break;
-			case "2":
-				empList = empDao.selectById​(Integer.parseInt(inputCheck("ID", true)));
-				break;
 			default:
 				return;
 			}
-			for (EmployeeDTO emp : empList) {
-				emp.showInfo();
+			for (String emp : empList) {
+				System.out.println(emp);
 			}
 		} finally {
 			DbUtil.closeConnection(empDao.con);
@@ -240,26 +146,4 @@ public class Main {
 		}
 		return str;
 	}
-
-	public static String inputCheck(boolean flg) {
-		String str = null;
-		while (true) {
-			str = sc.nextLine();
-			if (str.trim().length() == 0) {
-
-				continue;
-			}
-			if (flg) {
-				if (str.trim().length() > 0) {
-					try {
-						Integer.parseInt(str);
-					} catch (NumberFormatException e) {
-						continue;
-					}
-				}
-			}
-			break;
-		}
-		return str;
-	}
 }

src/com/rhizome/example/util/DbUtil.java

@@ -4,7 +4,6 @@ import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.PreparedStatement;
 import java.sql.SQLException;
-import java.util.Objects;
 
 public class DbUtil {
 	// 定数定義（共通）
@@ -45,13 +44,18 @@ public class DbUtil {
 	 * 				  生成されたConnectionを返却する
 	 * 				  ※Connection生成には上記の定数を活用してください
 	 */
-
 	public static Connection getConnection() throws ClassNotFoundException, SQLException {
-		if (con != null && con.isValid(1)) {
-			return con;
-		}
+		try {
 			Class.forName(DB_DRIVER);
-		return con = DriverManager.getConnection(DB_URL, DB_USER, DB_PASS);
+			return DriverManager.getConnection(DB_URL, DB_USER, DB_PASS);
+		} catch (ClassNotFoundException e) {
+			System.out.println();
+			throw e;
+		} catch (SQLException e) {
+			System.out.println();
+			throw e;
+		}
+
 	}
 
 	/*
@@ -63,10 +67,14 @@ public class DbUtil {
 	 * 例外			：SQLException
 	 * 処理			：引数のDBステートメントがnullでない場合、そのDBステートメントをクローズする
 	 */
-
-	public static void closeStatement(PreparedStatement ps) throws SQLException {
-		if (Objects.nonNull(ps))
-			ps.close();
+	public static void closeStatement(PreparedStatement stmt) {
+		if (stmt != null) {
+			try {
+				stmt.close();
+			} catch (SQLException e) {
+				System.out.println();
+			}
+		}
 	}
 
 	/*
@@ -78,9 +86,16 @@ public class DbUtil {
 	 * 例外			：SQLException
 	 * 処理			：引数のコネクションがnullでない場合、そのコネクションを切断する
 	 */
-	public static void closeConnection(Connection con) throws SQLException {
-		if (Objects.nonNull(con))
+	public static void closeConnection(Connection con) {
+		if (con != null) {
+			try {
+				if (!con.isClosed()) {
 					con.close();
 				}
+			} catch (SQLException e) {
+				e.printStackTrace();
+			}
+		}
+	}
 
 }