JAVA 19

19 negative integers. && accept username and password

Q1]

import java.util.*;

public class NegativeIntegers {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);

    System.out.print("Enter the value of N: ");
    int N = scanner.nextInt();

  
    LinkedList<Integer> numbers = new LinkedList<>();

  
    System.out.println("Enter " + N + " integers:");
    for (int i = 0; i < N; i++) {
        int num = scanner.nextInt();
        numbers.add(num);
    }

  
    System.out.println("Negative Integers:");
    for (int num : numbers) {
        if (num < 0) {
            System.out.println(num);
        }
    }

    scanner.close();
}

}

Q2]

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

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

static final String JDBC_URL = "jdbc:mysql://localhost:3306/your_database_name";
static final String USER = "your_username";
static final String PASSWORD = "your_password";

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    response.setContentType("text/html");
    PrintWriter out = response.getWriter();

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

    
    try (Connection conn = DriverManager.getConnection(JDBC_URL, USER, PASSWORD)) {
      
        String query = "SELECT * FROM Users WHERE username = ? AND password = ?";
        try (PreparedStatement pstmt = conn.prepareStatement(query)) {
            pstmt.setString(1, username);
            pstmt.setString(2, password);
            ResultSet rs = pstmt.executeQuery();

           
            if (rs.next()) {
                out.println("<h2>Login Successful!</h2>");
            } else {
         
                out.println("<h2>Error: Invalid username or password!</h2>");
            }
        }
    } catch (SQLException e) {
        e.printStackTrace();
    }
}

}