clicker/ClickerResponseServlet.java at main · roolimmm/clicker · GitHub

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import java.io.*;
import java.sql.*;
import jakarta.servlet.*;            // Tomcat 10 (Jakarta EE 9)
import jakarta.servlet.http.*;
import jakarta.servlet.annotation.*;
//import javax.servlet.*;            // Tomcat 9 (Java EE 8 / Jakarta EE 8)
//import javax.servlet.http.*;
//import javax.servlet.annotation.*;

@WebServlet("/select")   // Configure the request URL for this servlet (Tomcat 7/Servlet 3.0 upwards)
public class ClickerResponseServlet extends HttpServlet {

   // The doGet() runs once per HTTP GET request to this servlet.
   @Override
   public void doGet(HttpServletRequest request, HttpServletResponse response)
               throws ServletException, IOException {
      // Set the MIME type for the response message
      response.setContentType("text/html");
      // Get a output writer to write the response message into the network socket
      PrintWriter out = response.getWriter();
      // Print an HTML page as the output of the query
      out.println("<!DOCTYPE html>");
      out.println("<html>");
      out.println("<head><title>Query Response</title></head>");
      out.println("<body>");

      try (
         // Step 1: Allocate a database 'Connection' object
         Connection conn = DriverManager.getConnection(
               "jdbc:mysql://localhost:3306/clicker?allowPublicKeyRetrieval=true&useSSL=false&serverTimezone=UTC",
               "myuser", "xxxx");   // For MySQL
               // The format is: "jdbc:mysql://hostname:port/databaseName", "username", "password"

         // Step 2: Allocate a 'Statement' object in the Connection
         Statement stmt = conn.createStatement();
      ) {
         // Step 3 & 4 of the database servlet
         // Assume that the URL is http://ip-addr:port/clicker/select?choice=x
         // Assume that the questionNo is 8 String choice = request.getParameter("choice");

         String[] choice = request.getParameterValues("choice");

         if (choice != null) {
            // Prepare SQL statement to insert the choice into the responses table
            String sqlStr = "INSERT INTO responses (questionNo, choice) VALUES (8, '" + choice + "')";
            out.println("<p>SQL: " + sqlStr + "</p>");  // For debugging

            // Execute the SQL INSERT statement
            int count = stmt.executeUpdate(sqlStr);
         } else {
            // No choice was provided
            out.println("<h3>Error: No choice was selected.</h3>");
         }
      } catch(SQLException ex) {
         out.println("<p>Error: " + ex.getMessage() + "</p>");
         out.println("<p>Check Tomcat console for details.</p>");
         ex.printStackTrace();
      }  // Step 5: Close conn and stmt - Done automatically by try-with-resources (JDK 7)

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