api.conferences.ConferenceList.java Source code

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Here is the source code for api.conferences.ConferenceList.java

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/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package api.conferences;

import api.db.DBHandler;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Date;
import java.sql.SQLException;
import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.ServletConfig;
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 org.json.simple.JSONArray;
import org.json.simple.JSONObject;

/**
 *
 * @author guoweim
 */
@WebServlet(name = "ConferenceList", urlPatterns = { "/getConferenceList" })
public class ConferenceList extends HttpServlet {

    DBHandler db;

    @Override
    public void init(ServletConfig config) throws ServletException {
        super.init(config); //To change body of generated methods, choose Tools | Templates.

        this.connectToMySQL();
    }

    /**
     * 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 {
        // request { categoryId: 1 , categoryName: "" , timeStart: "",  timeEnd: "",  location: [] }
        String categoryId = request.getParameter("categoryId");
        String categoryName = request.getParameter("categoryName");

        String timeStart = request.getParameter("timeStart");
        String timeEnd = request.getParameter("timeEnd");

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

        if (categoryId != null) {
            Integer.parseInt(categoryId);
        }

        if (locations != null) {
            locations = locations.substring(1, locations.length() - 1);
        }

        List<Map<String, Object>> allResults = this.getAllConferences();
        JSONObject conferences = new JSONObject();
        JSONArray conferenceList = new JSONArray();
        for (Map<String, Object> result : allResults) {
            Iterator it = result.entrySet().iterator();
            JSONObject conference = new JSONObject();
            while (it.hasNext()) {
                Map.Entry pair = (Map.Entry) it.next();
                Object value = pair.getValue();
                System.out.println(pair.getKey() + " = " + value);
                if (value instanceof Timestamp) {
                    value = value.toString();
                }
                conference.put(pair.getKey(), value);

                it.remove(); // avoids a ConcurrentModificationException
            }
            conferenceList.add(conference);
        }

        conferences.put("conferences", conferenceList);

        response.setContentType("text/html;charset=UTF-8");
        try (PrintWriter out = response.getWriter()) {
            out.write(conferences.toJSONString());

            out.close();
        }

    }

    public void connectToMySQL() {
        db = new DBHandler();
        db.getConnection();
    }

    public List<Map<String, Object>> getAllConferences() {
        //{id, name, venue, time, image, category
        String queryStr = "SELECT id, name, city, startTime, imageUrl, categoryId, categoryName, cost FROM Rakett_ProConferences";
        List<Map<String, Object>> results = new ArrayList<>();
        try {
            results = db.findMultiResult(queryStr, null);
        } catch (SQLException ex) {
            Logger.getLogger(ConferenceList.class.getName()).log(Level.SEVERE, null, ex);
        }

        return results;
    }

    // <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>

}