mvcSample

model.dao.ConnectionManager.java


package model.dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class ConnectionManager {
	private final static String URL = "jdbc:postgresql://localhost:5432/mydb";
	private final static String USER = "postgres";
	private final static String PASSWORD = "xxxxxxxx";
//	private final static String URL = "jdbc:mysql://localhost:3306/sampledb";
//	private final static String USER = "userU";
//	private final static String PASSWORD = "userP";

	public static Connection getConnection() throws SQLException, ClassNotFoundException {
		// JDBCドライバの読み込み
		Class.forName("org.postgresql.Driver");
//		Class.forName("com.mysql.cj.jdbc.Driver");
		return DriverManager.getConnection(URL, USER, PASSWORD);
	}
}

model.dao.EmployeeDAO.java


package model.dao;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

import model.entity.EmployeeBean;

public class EmployeeDAO {
	public List＜EmployeeBean> selectAll() throws SQLException, ClassNotFoundException {

		List＜EmployeeBean> employeeList = new ArrayList＜EmployeeBean>();

		// データベースへの接続の取得、Statementの取得、SQLステートメントの実行
		try (Connection con = ConnectionManager.getConnection();
				Statement stmt = con.createStatement();
				ResultSet res = stmt.executeQuery("SELECT * FROM m_employee")) {

			// 結果の操作
			while (res.next()) {
				String code = res.getString("code");
				String name = res.getString("name");
				int age = res.getInt("age");
				String section = res.getString("section");

				EmployeeBean employee = new EmployeeBean();
				employee.setCode(code);
				employee.setName(name);
				employee.setAge(age);
				employee.setSection(section);

				employeeList.add(employee);
			}
		}
		return employeeList;
	}
}

model.entity.EmployeeBean.java


package model.entity;
import java.io.Serializable;

public class EmployeeBean implements Serializable {
	private String code;
	private String name;
	private int age;
	private String section;
	public EmployeeBean() {

	}
	public String getCode() {
		return code;
	}
	public void setCode(String code) {
		this.code = code;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public String getSection() {
		return section;
	}
	public void setSection(String section) {
		this.section = section;
	}
}

servlet.EmployeeListServlet.java


package servlet;
import java.io.IOException;
import java.sql.SQLException;
import java.util.List;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import model.dao.EmployeeDAO;
import model.entity.EmployeeBean;

@WebServlet("/employee-list-servlet")
public class EmployeeListServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	public EmployeeListServlet() {
		super();
		// TODO Auto-generated constructor stub
	}
	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		// TODO Auto-generated method stub
		response.getWriter().append("Served at: ").append(request.getContextPath());
	}
	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		List＜EmployeeBean> employeeList = null;
		// DAOの生成
		EmployeeDAO dao = new EmployeeDAO();
		try {
			// DAOの利用
			employeeList = dao.selectAll();
		} catch (SQLException | ClassNotFoundException e) {
			e.printStackTrace();
		}
		// リクエストスコープへの属性の設定
		request.setAttribute("employeeList", employeeList);
		// リクエストの転送
		RequestDispatcher rd = request.getRequestDispatcher("employee-list.jsp");
		rd.forward(request, response);
	}
}

employee-list.jsp


＜%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8" import="java.util.List,model.entity.EmployeeBean"%>
＜!DOCTYPE html>
＜html>
＜head>
＜meta charset="UTF-8">
＜title>従業員情報 一覧＜/title>
＜/head>
＜body>
	＜%
		List＜EmployeeBean> employeeList = (List) request.getAttribute("employeeList");
	%>
	＜table>
		＜tr>
			＜th>コード＜/th>
			＜th>氏名＜/th>
			＜th>年齢＜/th>
			＜th>部署＜/th>
		＜/tr>
		＜%
			for (EmployeeBean employee : employeeList) {
		%>
		＜tr>
			＜td>＜%=employee.getCode()%>＜/td>
			＜td>＜%=employee.getName()%>＜/td>
			＜td>＜%=employee.getAge()%>＜/td>
			＜td>＜%=employee.getSection()%>＜/td>
		＜/tr>
		＜%
			}
		%>
	＜/table>
＜/body>
＜/html>


＜!DOCTYPE html>
＜html>
＜head>
＜meta charset="UTF-8">
＜title>メニュー＜/title>
＜/head>
＜body>
	＜form action="employee-list-servlet" method="POST">
		＜input type="submit" value="一覧表示">
	＜/form>
＜/body>
＜/html>


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