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Build Todo App using JSP, Servlet, JDBC and MySQL - Part 2

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This is part 2 of Build Todo App using JSP, Servlet, JDBC and MySQL tutorial. 

 In this part 2, we create Todo management features such as add todo, update todo, list todo and delete todo.

Table of Contents

In part 2, I will cover the below topics:
  • Model Layer - Todo.java
  • DAO Layer - TodoDao.java and TodoDaoImpl.java
  • Controller Layer - TodoController.java
  • View Layer - todo-form.jsp and todo-list.jsp
  • Creating an error page

Model Layer - Todo.java

This is a model class represents a Todo entity:
package net.javaguides.todoapp.model;

import java.time.LocalDate;


/**
 * Todo.java
 * This is a model class represents a Todo entity
 * @author Ramesh Fadatare
 *
 */
public class Todo {

    private Long id;
    private String title;
    private String username;
    private String description;
    private LocalDate targetDate;
    private boolean status;

    protected Todo() {

    }

    public Todo(long id, String title, String username, String description, LocalDate targetDate, boolean isDone) {
        super();
        this.id = id;
        this.title = title;
        this.username = username;
        this.description = description;
        this.targetDate = targetDate;
        this.status = isDone;
    }

    public Todo(String title, String username, String description, LocalDate targetDate, boolean isDone) {
        super();
        this.title = title;
        this.username = username;
        this.description = description;
        this.targetDate = targetDate;
        this.status = isDone;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public LocalDate getTargetDate() {
        return targetDate;
    }

    public void setTargetDate(LocalDate targetDate) {
        this.targetDate = targetDate;
    }

    public boolean getStatus() {
        return status;
    }

    public void setStatus(boolean status) {
        this.status = status;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + (int)(id ^ (id >>> 32));
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Todo other = (Todo) obj;
        if (id != other.id)
            return false;
        return true;
    }
}

DAO Layer - TodoDao.java and TodoDaoImpl.java

TodoDao.java

Let's create a TodoDao interface with following methods:
package net.javaguides.todoapp.dao;

import java.sql.SQLException;
import java.util.List;

import net.javaguides.todoapp.model.Todo;

public interface TodoDao {

 void insertTodo(Todo todo) throws SQLException;

 Todo selectTodo(long todoId);

 List<Todo> selectAllTodos();

 boolean deleteTodo(int id) throws SQLException;

 boolean updateTodo(Todo todo) throws SQLException;

}

TodoDaoImpl.java

This DAO class provides CRUD database operations for the table todos in the database.
package net.javaguides.todoapp.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.time.LocalDate;
import java.util.ArrayList;
import java.util.List;

import net.javaguides.todoapp.model.Todo;
import net.javaguides.todoapp.utils.JDBCUtils;

/**
 * This DAO class provides CRUD database operations for the table todos in the
 * database.
 * 
 * @author Ramesh Fadatare
 *
 */

public class TodoDaoImpl implements TodoDao {

    private static final String INSERT_TODOS_SQL = "INSERT INTO todos" +
        "  (title, username, description, target_date,  is_done) VALUES " + " (?, ?, ?, ?, ?);";

    private static final String SELECT_TODO_BY_ID = "select id,title,username,description,target_date,is_done from todos where id =?";
    private static final String SELECT_ALL_TODOS = "select * from todos";
    private static final String DELETE_TODO_BY_ID = "delete from todos where id = ?;";
    private static final String UPDATE_TODO = "update todos set title = ?, username= ?, description =?, target_date =?, is_done = ? where id = ?;";

    public TodoDaoImpl() {}

    @Override
    public void insertTodo(Todo todo) throws SQLException {
        System.out.println(INSERT_TODOS_SQL);
        // try-with-resource statement will auto close the connection.
        try (Connection connection = JDBCUtils.getConnection(); PreparedStatement preparedStatement = connection.prepareStatement(INSERT_TODOS_SQL)) {
            preparedStatement.setString(1, todo.getTitle());
            preparedStatement.setString(2, todo.getUsername());
            preparedStatement.setString(3, todo.getDescription());
            preparedStatement.setDate(4, JDBCUtils.getSQLDate(todo.getTargetDate()));
            preparedStatement.setBoolean(5, todo.getStatus());
            System.out.println(preparedStatement);
            preparedStatement.executeUpdate();
        } catch (SQLException exception) {
            JDBCUtils.printSQLException(exception);
        }
    }

    @Override
    public Todo selectTodo(long todoId) {
        Todo todo = null;
        // Step 1: Establishing a Connection
        try (Connection connection = JDBCUtils.getConnection();
            // Step 2:Create a statement using connection object
            PreparedStatement preparedStatement = connection.prepareStatement(SELECT_TODO_BY_ID);) {
            preparedStatement.setLong(1, todoId);
            System.out.println(preparedStatement);
            // Step 3: Execute the query or update query
            ResultSet rs = preparedStatement.executeQuery();

            // Step 4: Process the ResultSet object.
            while (rs.next()) {
                long id = rs.getLong("id");
                String title = rs.getString("title");
                String username = rs.getString("username");
                String description = rs.getString("description");
                LocalDate targetDate = rs.getDate("target_date").toLocalDate();
                boolean isDone = rs.getBoolean("is_done");
                todo = new Todo(id, title, username, description, targetDate, isDone);
            }
        } catch (SQLException exception) {
            JDBCUtils.printSQLException(exception);
        }
        return todo;
    }

    @Override
    public List < Todo > selectAllTodos() {

        // using try-with-resources to avoid closing resources (boiler plate code)
        List < Todo > todos = new ArrayList < > ();

        // Step 1: Establishing a Connection
        try (Connection connection = JDBCUtils.getConnection();

            // Step 2:Create a statement using connection object
            PreparedStatement preparedStatement = connection.prepareStatement(SELECT_ALL_TODOS);) {
            System.out.println(preparedStatement);
            // Step 3: Execute the query or update query
            ResultSet rs = preparedStatement.executeQuery();

            // Step 4: Process the ResultSet object.
            while (rs.next()) {
                long id = rs.getLong("id");
                String title = rs.getString("title");
                String username = rs.getString("username");
                String description = rs.getString("description");
                LocalDate targetDate = rs.getDate("target_date").toLocalDate();
                boolean isDone = rs.getBoolean("is_done");
                todos.add(new Todo(id, title, username, description, targetDate, isDone));
            }
        } catch (SQLException exception) {
            JDBCUtils.printSQLException(exception);
        }
        return todos;
    }

    @Override
    public boolean deleteTodo(int id) throws SQLException {
        boolean rowDeleted;
        try (Connection connection = JDBCUtils.getConnection(); PreparedStatement statement = connection.prepareStatement(DELETE_TODO_BY_ID);) {
            statement.setInt(1, id);
            rowDeleted = statement.executeUpdate() > 0;
        }
        return rowDeleted;
    }

    @Override
    public boolean updateTodo(Todo todo) throws SQLException {
        boolean rowUpdated;
        try (Connection connection = JDBCUtils.getConnection(); PreparedStatement statement = connection.prepareStatement(UPDATE_TODO);) {
            statement.setString(1, todo.getTitle());
            statement.setString(2, todo.getUsername());
            statement.setString(3, todo.getDescription());
            statement.setDate(4, JDBCUtils.getSQLDate(todo.getTargetDate()));
            statement.setBoolean(5, todo.getStatus());
            statement.setLong(6, todo.getId());
            rowUpdated = statement.executeUpdate() > 0;
        }
        return rowUpdated;
    }
}

Controller Layer - TodoController

This servlet acts as a page controller for the application, handling all requests from the todo. This TodoController class to process HTTP request parameters and redirect to the appropriate JSP page after request data stored in the database:
package net.javaguides.todoapp.web;

import java.io.IOException;
import java.sql.SQLException;
import java.time.LocalDate;
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 net.javaguides.todoapp.dao.TodoDao;
import net.javaguides.todoapp.dao.TodoDaoImpl;
import net.javaguides.todoapp.model.Todo;

/**
 * ControllerServlet.java This servlet acts as a page controller for the
 * application, handling all requests from the todo.
 * 
 * @email Ramesh Fadatare
 */

@WebServlet("/")
public class TodoController extends HttpServlet {
    private static final long serialVersionUID = 1 L;
    private TodoDao todoDAO;

    public void init() {
        todoDAO = new TodoDaoImpl();
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        doGet(request, response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        String action = request.getServletPath();

        try {
            switch (action) {
                case "/new":
                    showNewForm(request, response);
                    break;
                case "/insert":
                    insertTodo(request, response);
                    break;
                case "/delete":
                    deleteTodo(request, response);
                    break;
                case "/edit":
                    showEditForm(request, response);
                    break;
                case "/update":
                    updateTodo(request, response);
                    break;
                case "/list":
                    listTodo(request, response);
                    break;
                default:
                    RequestDispatcher dispatcher = request.getRequestDispatcher("login/login.jsp");
                    dispatcher.forward(request, response);
                    break;
            }
        } catch (SQLException ex) {
            throw new ServletException(ex);
        }
    }

    private void listTodo(HttpServletRequest request, HttpServletResponse response)
    throws SQLException, IOException, ServletException {
        List < Todo > listTodo = todoDAO.selectAllTodos();
        request.setAttribute("listTodo", listTodo);
        RequestDispatcher dispatcher = request.getRequestDispatcher("todo/todo-list.jsp");
        dispatcher.forward(request, response);
    }

    private void showNewForm(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        RequestDispatcher dispatcher = request.getRequestDispatcher("todo/todo-form.jsp");
        dispatcher.forward(request, response);
    }

    private void showEditForm(HttpServletRequest request, HttpServletResponse response)
    throws SQLException, ServletException, IOException {
        int id = Integer.parseInt(request.getParameter("id"));
        Todo existingTodo = todoDAO.selectTodo(id);
        RequestDispatcher dispatcher = request.getRequestDispatcher("todo/todo-form.jsp");
        request.setAttribute("todo", existingTodo);
        dispatcher.forward(request, response);

    }

    private void insertTodo(HttpServletRequest request, HttpServletResponse response) throws SQLException, IOException {

        String title = request.getParameter("title");
        String username = request.getParameter("username");
        String description = request.getParameter("description");

        /*DateTimeFormatter df = DateTimeFormatter.ofPattern("yyyy-mm-dd");
        LocalDate targetDate = LocalDate.parse(request.getParameter("targetDate"),df);*/

        boolean isDone = Boolean.valueOf(request.getParameter("isDone"));
        Todo newTodo = new Todo(title, username, description, LocalDate.now(), isDone);
        todoDAO.insertTodo(newTodo);
        response.sendRedirect("list");
    }

    private void updateTodo(HttpServletRequest request, HttpServletResponse response) throws SQLException, IOException {
        int id = Integer.parseInt(request.getParameter("id"));

        String title = request.getParameter("title");
        String username = request.getParameter("username");
        String description = request.getParameter("description");
        //DateTimeFormatter df = DateTimeFormatter.ofPattern("yyyy-mm-dd");
        LocalDate targetDate = LocalDate.parse(request.getParameter("targetDate"));

        boolean isDone = Boolean.valueOf(request.getParameter("isDone"));
        Todo updateTodo = new Todo(id, title, username, description, targetDate, isDone);

        todoDAO.updateTodo(updateTodo);

        response.sendRedirect("list");
    }

    private void deleteTodo(HttpServletRequest request, HttpServletResponse response) throws SQLException, IOException {
        int id = Integer.parseInt(request.getParameter("id"));
        todoDAO.deleteTodo(id);
        response.sendRedirect("list");
    }
}

View Layer - todo-form.jsp and todo-list.jsp

todo-form.jsp

Let' create a "todo-form.jsp" page to add and edit a todo. Let's create todo-form.jsp file and add following code to it.
<%@ page language="java" contentType="text/html; charset=UTF-8"
 pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<html>
<head>
<title>User Management Application</title>

<link rel="stylesheet"
 href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css"
 integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T"
 crossorigin="anonymous">

</head>

</head>
<body>
 <header>
  <nav class="navbar navbar-expand-md navbar-dark"
   style="background-color: tomato">
   <div>
    <a href="https://www.javaguides.net" class="navbar-brand"> Todo
     App</a>
   </div>

   <ul class="navbar-nav">
    <li><a href="<%=request.getContextPath()%>/list"
     class="nav-link">Todos</a></li>
   </ul>

   <ul class="navbar-nav navbar-collapse justify-content-end">
    <li><a href="<%=request.getContextPath()%>/logout"
     class="nav-link">Logout</a></li>
   </ul>
  </nav>
 </header>
 <div class="container col-md-5">
  <div class="card">
   <div class="card-body">
    <c:if test="${todo != null}">
     <form action="update" method="post">
    </c:if>
    <c:if test="${todo == null}">
     <form action="insert" method="post">
    </c:if>

    <caption>
     <h2>
      <c:if test="${todo != null}">
               Edit Todo
              </c:if>
      <c:if test="${todo == null}">
               Add New Todo
              </c:if>
     </h2>
    </caption>

    <c:if test="${todo != null}">
     <input type="hidden" name="id" value="<c:out value='${todo.id}' />" />
    </c:if>

    <fieldset class="form-group">
     <label>Todo Title</label> <input type="text"
      value="<c:out value='${todo.title}' />" class="form-control"
      name="title" required="required" minlength="5">
    </fieldset>

    <fieldset class="form-group">
     <label>Todo Decription</label> <input type="text"
      value="<c:out value='${todo.description}' />" class="form-control"
      name="description" minlength="5">
    </fieldset>

    <fieldset class="form-group">
     <label>Todo Status</label> <select class="form-control"
      name="isDone">
      <option value="false">In Progress</option>
      <option value="true">Complete</option>
     </select>
    </fieldset>

    <fieldset class="form-group">
     <label>Todo Target Date</label> <input type="date"
      value="<c:out value='${todo.targetDate}' />" class="form-control"
      name="targetDate" required="required">
    </fieldset>

    <button type="submit" class="btn btn-success">Save</button>
    </form>
   </div>
  </div>
 </div>

 <jsp:include page="../common/footer.jsp"></jsp:include>
</body>
</html>

todo-list.jsp

This page list out all the todos. Let's create "todo-list.jsp" file and add following code to it:
<%@ page language="java" contentType="text/html; charset=UTF-8"
 pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<html>
<head>
<title>User Management Application</title>

<link rel="stylesheet"
 href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css"
 integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T"
 crossorigin="anonymous">
</head>

</head>
<body>
 <header>
  <nav class="navbar navbar-expand-md navbar-dark"
   style="background-color: tomato">
   <div>
    <a href="https://www.javaguides.net" class="navbar-brand"> Todo
     App</a>
   </div>

   <ul class="navbar-nav">
    <li><a href="<%=request.getContextPath()%>/list"
     class="nav-link">Todos</a></li>
   </ul>

   <ul class="navbar-nav navbar-collapse justify-content-end">
    <li><a href="<%=request.getContextPath()%>/logout"
     class="nav-link">Logout</a></li>
   </ul>
  </nav>
 </header>

 <div class="row">
  <!-- <div class="alert alert-success" *ngIf='message'>{{message}}</div> -->

  <div class="container">
   <h3 class="text-center">List of Todos</h3>
   <hr>
   <div class="container text-left">

    <a href="<%=request.getContextPath()%>/new"
     class="btn btn-success">Add Todo</a>
   </div>
   <br>
   <table class="table table-bordered">
    <thead>
     <tr>
      <th>Title</th>
      <th>Target Date</th>
      <th>Todo Status</th>
      <th>Actions</th>
     </tr>
    </thead>
    <tbody>
     <!--   for (Todo todo: todos) {  -->
     <c:forEach var="todo" items="${listTodo}">

      <tr>
       <td><c:out value="${todo.title}" /></td>
       <td><c:out value="${todo.targetDate}" /></td>
       <td><c:out value="${todo.status}" /></td>

       <td><a href="edit?id=<c:out value='${todo.id}' />">Edit</a>
        &nbsp;&nbsp;&nbsp;&nbsp; <a
        href="delete?id=<c:out value='${todo.id}' />">Delete</a></td>

       <!--  <td><button (click)="updateTodo(todo.id)" class="btn btn-success">Update</button>
                 <button (click)="deleteTodo(todo.id)" class="btn btn-warning">Delete</button></td> -->
      </tr>
     </c:forEach>
     <!-- } -->
    </tbody>

   </table>
  </div>
 </div>

 <jsp:include page="../common/footer.jsp"></jsp:include>
</body>
</html>

Creating Error JSP page

Here’s the code of the Error.jsp page which simply shows the exception message:
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8" isErrorPage="true" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" 
 "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Error</title>
</head>
<body>
 <center>
  <h1>Error</h1>
  <h2><%=exception.getMessage() %><br/> </h2>
 </center> 
</body>
</html>
Configure above error page in web.xml file as:
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xmlns="http://xmlns.jcp.org/xml/ns/javaee"
 xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee 
  http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
 id="WebApp_ID" version="3.1">
 <display-name>Todo Management Web Application</display-name>

 <error-page>
  <exception-type>java.lang.Exception</exception-type>
  <location>/Error.jsp</location>
 </error-page>
</web-app>

Move to Part 3 - Deployment and Demo

Next part,  we will deploy our Todo web application in tomcat server and we will see the demo. Click here at Build Todo App using JSP, Servlet, JDBC, and MySQL - Part 3.

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