Savitribai Phule Pune University T.Y.B.B.A.(C.A.) Advanced Java Practical Slip 23 Answers

Q.1. Advanced Java:

A) Write a Java Program to display the details of College(CID, CName, address, Year)

on JTable.

Answer :

import java.sql.*;

import javax.swing.*;

import javax.swing.table.DefaultTableModel;

public class CollegeDetailsProgram extends JFrame {

    private JTable table;

    public CollegeDetailsProgram() {

        setTitle("College Details");

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        setSize(500, 500);

        // Create a table model with column names

        String[] columnNames = {"CID", "CName", "Address", "Year"};

        DefaultTableModel model = new DefaultTableModel(columnNames, 0);

        // Connect to the database and retrieve the college details

        try {

            // Step 1: Load the JDBC driver

            Class.forName("com.mysql.jdbc.Driver");

            // Step 2: Establish the connection to the database

            String url = "jdbc:mysql://localhost/mydatabase";

            String username = "root";

            String password = "password";

            Connection connection = DriverManager.getConnection(url, username, password);

            // Step 3: Retrieve the college details from the database

            String query = "SELECT * FROM college";

            Statement statement = connection.createStatement();

            ResultSet resultSet = statement.executeQuery(query);

            while (resultSet.next()) {

                String cid = resultSet.getString("CID");

                String cname = resultSet.getString("CName");

                String address = resultSet.getString("Address");

                int year = resultSet.getInt("Year");

                model.addRow(new Object[]{cid, cname, address, year});

            }

            // Step 4: Close the database resources

            resultSet.close();

            statement.close();

            connection.close();

        } catch (ClassNotFoundException e) {

            System.out.println("JDBC driver not found.");

        } catch (SQLException e) {

            System.out.println("SQL exception occurred: " + e.getMessage());

        }

        // Create the JTable and add it to the JFrame

        table = new JTable(model);

        JScrollPane scrollPane = new JScrollPane(table);

        add(scrollPane);

        // Show the JFrame

        setVisible(true);

    }

    public static void main(String[] args) {

        new CollegeDetailsProgram();

    }

}

Output :

 

B) Write a SERVLET application to accept username and password, search them into

database, if found then display appropriate message on the browser otherwise display

error message.

Answer :

import java.io.*;

import java.sql.*;

import java.util.Properties;

import javax.servlet.*;

import javax.servlet.http.*;

public class LoginServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;

    private Connection connection;

    @Override

    public void init() throws ServletException {

        // Load database configuration from properties file

        Properties props = new Properties();

        try {

            props.load(getServletContext().getResourceAsStream("/dbconfig.properties"));

            String dbUrl = props.getProperty("db.url");

            String dbUsername = props.getProperty("db.username");

            String dbPassword = props.getProperty("db.password");

            // Establish a connection to the database

            connection = DriverManager.getConnection(dbUrl, dbUsername, dbPassword);

        } catch (IOException | SQLException e) {

            throw new ServletException("Failed to initialize database connection.", e);

        }

    }

    @Override

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        doPost(request, response);

    }

    @Override

    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        // Get the username and password from the request parameters

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

        String password = request.getParameter("password");

        // Check if the username and password are valid

        boolean isValidUser = false;

        try {

            String sql = "SELECT * FROM users WHERE username = ? AND password = ?";

            PreparedStatement statement = connection.prepareStatement(sql);

            statement.setString(1, username);

            statement.setString(2, password);

            ResultSet resultSet = statement.executeQuery();

            isValidUser = resultSet.next();

            statement.close();

        } catch (SQLException e) {

            throw new ServletException("Failed to search for user.", e);

        }

        // Send appropriate response based on search results

        if (isValidUser) {

            response.setContentType("text/html");

            PrintWriter out = response.getWriter();

            out.println("<html><body>");

            out.println("<h2>Welcome, " + username + "!</h2>");

            out.println("</body></html>");

        } else {

            response.sendError(HttpServletResponse.SC_UNAUTHORIZED, "Invalid username or password.");

        }

    }

    @Override

    public void destroy() {

        // Close the database connection

        try {

            connection.close();

        } catch (SQLException e) {

            throw new RuntimeException("Failed to close database connection.", e);

        }

    }

}

Output :