Mvc Java Example With Database
JSP Servlet MVC Example with Database
In this quick article, we'll create a small web application that implements theModel View Controller (MVC) design pattern using basic Servlets and JSPs.
Model-View-Controller (MVC) is a pattern used in software engineering to separate the application logic from the user interface. As the name implies, the MVC pattern has three layers.
TheModel defines the business layer of the application, theController manages the flow of the application, and theView defines the presentation layer of the application.
Video
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Model-View-Controller (MVC) Architecture
From the above diagram, here is MVC flow:
1. The web browser sends an HTTP request to a controller (Servlet).
2. The controller (servlet) gets a model object with data from the database or other sources.
3. The controller(servlet) redirects to a web page (JSP) with model data.
4. Finally, the web page(JSP) will be displayed with model data on the browser.
Model-View-Controller Layers
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The Model Layer - This is the data layer that contains the business logic of the system, and also represents the state of the application. It's independent of the presentation layer, the controller fetches the data from the Model layer and sends it to the View layer.
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The Controller Layer - The controllerlayer acts as an interface betweenViewandModel. It receives requests from theViewlayer and processes them, including the necessary validations.
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The View Layer - This layer represents the output of the application, usually some form of UI. The presentation layer is used to display theModeldata fetched by theController.
Java MVC Example using JSP, Servlet with Database Example
To implement a web application based on the MVC design pattern, we'll create anEmployee Registration module usingJSP,Servlet,JDBC, andMySQL database.
EmployeeServlet class will act as aController, and for the presentation layer, we'll createemployees.jsp page.
Before getting started, let's first set up the database.
1. MySQL Database Setup
Let's create a database named "mysql_database" in MySQL. Let's create an employee table using below DDL script:
CREATE TABLE `employee` ( `id` int(3) NOT NULL, `first_name` varchar(20) DEFAULT NULL, `last_name` varchar(20) DEFAULT NULL, `username` varchar(250) DEFAULT NULL, `password` varchar(20) DEFAULT NULL, `address` varchar(45) DEFAULT NULL, `contact` varchar(45) DEFAULT NULL, PRIMARY KEY ( `id` ) ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci; SELECT * FROM mysql_database.employee; 2. Model Layer
Let's create theEmployee class which will act as ourModel class.
Employee
package net.javaguides.jsp.jdbc.bean; import java.io.Serializable; /** * JavaBean class used in jsp action tags. * @author Ramesh Fadatare */ public class Employee implements Serializable { /** * */ private static final long serialVersionUID = 1 L; private String firstName; private String lastName; private String username; private String password; private String address; private String contact; public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this .firstName = firstName; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this .lastName = lastName; } public String getUsername() { return username; } public void setUsername(String username) { this .username = username; } public String getPassword() { return password; } public void setPassword(String password) { this .password = password; } public String getAddress() { return address; } public void setAddress(String address) { this .address = address; } public String getContact() { return contact; } public void setContact(String contact) { this .contact = contact; } } 3. DAO Layer
EmployeeDao.java
Let's create EmployeeDao class that contains JDBC code to connect with the MySQL database.
Add the following code to anEmployeeDao class:
package net.javaguides.jsp.jdbc.database; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.SQLException; import net.javaguides.jsp.jdbc.bean.Employee; public class EmployeeDao { public int registerEmployee(Employee employee) throws ClassNotFoundException { String INSERT_USERS_SQL = "INSERT INTO employee" + " (id, first_name, last_name, username, password, address, contact) VALUES " + " (?, ?, ?, ?, ?,?,?);" ; int result = 0; Class .forName( "com.mysql.jdbc.Driver" ); try (Connection connection = DriverManager .getConnection( "jdbc:mysql://localhost:3306/mysql_database?useSSL=false" , "root" , "root" ); // Step 2:Create a statement using connection object PreparedStatement preparedStatement = connection.prepareStatement(INSERT_USERS_SQL)) { preparedStatement.setInt(1, 1); preparedStatement.setString(2, employee.getFirstName()); preparedStatement.setString(3, employee.getLastName()); preparedStatement.setString(4, employee.getUsername()); preparedStatement.setString(5, employee.getPassword()); preparedStatement.setString(6, employee.getAddress()); preparedStatement.setString(7, employee.getContact()); System .out.println(preparedStatement); // Step 3: Execute the query or update query result = preparedStatement.executeUpdate(); } catch (SQLException e) { // process sql exception printSQLException(e); } return result; } private void printSQLException(SQLException ex) { for (Throwable e: ex) { if (e instanceof SQLException) { e.printStackTrace(System .err); System .err.println( "SQLState: " + ((SQLException) e).getSQLState()); System .err.println( "Error Code: " + ((SQLException) e).getErrorCode()); System .err.println( "Message: " + e.getMessage()); Throwable t = ex.getCause(); while (t != null) { System .out.println( "Cause: " + t); t = t.getCause(); } } } } } 4. Controller Layer
Let's create an EmployeeServlet class to process HTTP request parameters and redirect to the appropriate JSP page after request data stored in the database:
package net.javaguides.employeemanagement.web; import java.io.IOException; 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.employeemanagement.dao.EmployeeDao; import net.javaguides.employeemanagement.model.Employee; /** * @email Ramesh Fadatare */ @WebServlet( "/register" ) public class EmployeeServlet extends HttpServlet { private static final long serialVersionUID = 1 L; private EmployeeDao employeeDao; public void init() { employeeDao = new EmployeeDao(); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String firstName = request.getParameter( "firstName" ); String lastName = request.getParameter( "lastName" ); String username = request.getParameter( "username" ); String password = request.getParameter( "password" ); String address = request.getParameter( "address" ); String contact = request.getParameter( "contact" ); Employee employee = new Employee(); employee.setFirstName(firstName); employee.setLastName(lastName); employee.setUsername(username); employee.setPassword(password); employee.setContact(contact); employee.setAddress(address); try { employeeDao.registerEmployee(employee); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } response.sendRedirect( "employeedetails.jsp" ); } }
5. View Layer
employeeregister.jsp
Let's design an employee registration HTML form with the following fields:
- firstName
- lastName
- username
- password
- address
- contact
<%@ page language= "java" contentType= "text/html; charset=ISO-8859-1" pageEncoding= "ISO-8859-1" %> <!DOCTYPE html> <html> <head> <meta charset= "ISO-8859-1" > <title>Insert title here</title> </head> <body> <div align= "center" > <h1>Employee Register Form</h1> <form action= " <%= request.getContextPath() %>/register" method= "post" > <table style= " with: 80% " > <tr> <td>First Name</td> <td><input type= "text" name= "firstName" /></td> </tr> <tr> <td>Last Name</td> <td><input type= "text" name= "lastName" /></td> </tr> <tr> <td>UserName</td> <td><input type= "text" name= "username" /></td> </tr> <tr> <td>Password</td> <td><input type= "password" name= "password" /></td> </tr> <tr> <td>Address</td> <td><input type= "text" name= "address" /></td> </tr> <tr> <td>Contact No</td> <td><input type= "text" name= "contact" /></td> </tr> </table> <input type= "submit" value= "Submit" /> </form> </div> </body> </html>
employeedetails.jsp
After an employee successfully registered then this page show a successful message on screen:
<%@ page language= "java" contentType= "text/html; charset=ISO-8859-1" pageEncoding= "ISO-8859-1" %> <%@page import= "net.javaguides.employeemanagement.dao.*" %> <!DOCTYPE html> <html> <head> <meta charset= "ISO-8859-1" > <title>Insert title here</title> </head> <body> <h1>User successfully registered!</h1> </body> </html>
6. Demo
It's time to see a demo of the above development. Deploy this web application to the tomcat server.
Employee Registration
Registration Success Page
Conclusion
In this tutorial, we've learned about the MVC i.e.Model View Controller architecture, and we focused on how to implement a simple MVC web application using JSP and Servlet.
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Source: https://www.javaguides.net/2020/01/jsp-servlet-mvc-example-with-database.html
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