City_Servlet.java Source code

Introduction

Here is the source code for City_Servlet.java

Source

/*
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 */

import com.google.gson.Gson;
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.util.ArrayList;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 *
 * @author Vaibhav
 */
public class City_Servlet extends HttpServlet {

    /**
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code>
     * methods.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        try (PrintWriter out = response.getWriter()) {

            try {
                String state = request.getParameter("state");
                String JDBC_driver = "com.mysql.jdbc.Driver";
                String DB_URL = "jdbc:mysql://localhost:3306/wheels_on_rent";
                Class.forName(JDBC_driver);
                String db_user = "root";
                String db_pass = "";

                Connection conn = DriverManager.getConnection(DB_URL, db_user, db_pass);
                String query = "SELECT `City` FROM `india_states_cities` WHERE"
                        + "`State/Union Territory` =? AND `City` IS NOT NULL";
                PreparedStatement pst = conn.prepareStatement(query);
                pst.setString(1, state);
                ResultSet rs = pst.executeQuery();

                String json;
                ArrayList<City> listCity = new ArrayList<City>();
                if (!rs.next()) {
                    out.print("rs is null");
                }
                while (rs.next()) {
                    City c = new City();
                    c.setCity_name(rs.getString("City"));

                    listCity.add(c);
                }
                Gson g = new Gson();

                json = g.toJson(listCity);
                out.print(json);

                rs.close();
                pst.close();
                conn.close();
            } catch (Exception ex) {
                out.print("error" + ex.getMessage());
            }
        } catch (IOException ex) {
            Logger.getLogger(State_Servlet.class.getName()).log(Level.SEVERE, null, ex);
        }

    }

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /**
     * Handles the HTTP <code>GET</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Handles the HTTP <code>POST</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Returns a short description of the servlet.
     *
     * @return a String containing servlet description
     */
    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>

}