import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.*;


public class Servlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
        this.process(request, response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {
        this.process(request, response);
    }

    /*
       generate the page showing all the request parameters
     */
    private void process(HttpServletRequest request, HttpServletResponse response) throws IOException {
        response.setStatus(200);



        PrintWriter out = response.getWriter();
        response.setContentType("text/plain");

        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
            out.println("Driver is not loaded");
            out.close();
            return;
        }

        Connection conn;
        Statement st = null;
        ResultSet rs;
        try {
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydict","root", "root");
            st = conn.createStatement();
            String selectTableSQL = "SELECT VALUE FROM MYTABLE WHERE " +
                    "MYKEY=" + "'" + request.getParameter("key")
                    +"'";
            rs = st.executeQuery(selectTableSQL);
            boolean fl = true;
            while (rs.next()) {
                fl = false;
                String value = rs.getString("value");
                if (value != null) {
                    out.println(value);
                }
            }
            if (fl){
                out.println("There is no element with this key");
            }
        } catch (SQLException e) {
            e.printStackTrace();
            out.println("Couldn't connect to database");
        }
        out.close();
    }
}