Sending GET and POST methods from server to client side (JavaFX) - javafx

Question

I have a simple login servlet which checks the email and password if the user is registered or not , now I'm trying to work on a JavaFX app which does the same job by reading from the servlet the information, my servlet works perfect but I don't know how to interact with my servlet from JavaFX , how can I send a response from the servlet to JavaFX ? I've searched a lot but couldn't find anything
Here's my servlet :
import java.io.*;
import java.security.Principal;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import jakarta.servlet.RequestDispatcher;
import jakarta.servlet.ServletConfig;
import jakarta.servlet.ServletContext;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpSession;
#WebServlet("/HelloServlet")
public class HelloServlet extends HttpServlet {
//int attempts = 3;
Date date;
/**
*
*/
private static final long serialVersionUID = -5498866193863633001L;
/**
* HashMap to store all users credentials
*/
private final Map<String, String> credentialsPairs = new HashMap<>();
#Override
public void init(ServletConfig config) throws ServletException {
String delimiter = ",";
String line = "";
/**
* Credentials file will be there in WEB-INF directory as it provide secured
* access only.
*/
String credentialFile = "/WEB-INF/accounts.txt";
/**
* Read the file and prepare Map with username as key and password as value We
* have put this code in init method as it is called once only that will avoid
* overhead of iterating values from file for each request
*/
InputStream is = null;
InputStreamReader isr = null;
BufferedReader br = null;
ServletContext context = config.getServletContext();
try {
/**
* Open stream of file
*/
is = context.getResourceAsStream(credentialFile);
if (is != null) {
/**
* Read the file line by line and store email as a key and password as value
*/
isr = new InputStreamReader(is);
br = new BufferedReader(isr);
while ((line = br.readLine()) != null) {
String[] credentials = line.split(delimiter);
// credentials[0] is email and credentials[1] is password
credentialsPairs.put(credentials[0], credentials[1]);
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (br != null) {
br.close();
}
if (isr != null) {
isr.close();
}
if (is != null) {
is.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
public void service(HttpServletRequest request, HttpServletResponse response) throws
IOException, ServletException {
/**
* Get user entered credentials
*/
String userEmail = request.getParameter("email");
String userPassword = request.getParameter("password");
PrintWriter out = response.getWriter();
boolean isValidUser = false;
/**
* Get value from Map for user entered email address.
*/
String password = credentialsPairs.get(userEmail);
/**
* If User with entered email address found then we will get password for that
* user
*/
if (password != null) {
/**
* Compare password entered by user with one that is retrieved from file
*/
if (password.equals(userPassword)) {
isValidUser = true;
}
}
}
HttpSession session = request.getSession();
if (isValidUser) {
//HttpSession session = request.getSession();
session.setAttribute("email", userEmail);
//request.getRequestDispatcher("welcome.jsp").include(request, response);
response.sendRedirect("welcome.jsp");
//response.setContentType("text/html");
//response.sendError(HttpServletResponse.SC_FOUND,"Hello");
}
else {
int loginAttempt;
if (session.getAttribute("loginCount") == null)
{
session.setAttribute("loginCount", 0);
loginAttempt = 0;
}
else
{
loginAttempt = (Integer) session.getAttribute("loginCount");
}
//this is 3 attempt counting from 0,1,2
if (loginAttempt >= 2 )
{
long lastAccessedTime = session.getLastAccessedTime();
date = new Date();
long currentTime = date.getTime();
long timeDiff = currentTime - lastAccessedTime;
// 20 minutes in milliseconds
if (timeDiff >= 1200000)
{
//invalidate user session, so they can try again
session.invalidate();
}
else
{
// Error message
session.setAttribute("message","You have exceeded the 3 failed login
attempt. Please try loggin in in 20 minutes.");
//request.getRequestDispatcher("fail.jsp");
out.println("You have exceeded the 3 failed login attempt. Please
try loggin in in 20 minutes.");
}
}
else
{
loginAttempt++;
int allowLogin = 3-loginAttempt;
session.setAttribute("message","loginAttempt= "+loginAttempt+". Invalid
username or password. You have "+allowLogin+" attempts remaining. Please try again!");
out.println("Invalid email or password , please try again");
final String message = "The requested page not found";
response.sendError(HttpServletResponse.SC_NOT_FOUND,message);
}
session.setAttribute("loginCount",loginAttempt);
}
}
public void destroy() {
/**
* Free up the map
*/
credentialsPairs.clear();
}
}
Here's my JavaFX code :
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.ComboBox;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
public class HelloApplication extends Application {
TextField tName;
TextField tPassword;
ComboBox comboBox;
Button login;
VBox vBox;
BorderPane borderPane;
URL url = null;
HttpURLConnection con = null;
int flag =0;
#Override
public void start(Stage stage) throws IOException {
stage.setTitle("login Page");
stage.setResizable(false);
setDesign();
comboBox.setOnAction(e->{
if(comboBox.getSelectionModel().isSelected(0)){
flag =0;
}else if (comboBox.getSelectionModel().isSelected(1)){
flag =1;
}
});
login.setOnAction(e->{
if(flag==0){
try {
System.out.println("get");
String name =tName.getText();
String password =tPassword.getText();
url = new URL("http://localhost:8080/try8_war_exploded/login?
email="+name+"&password="+password);
con = (HttpURLConnection)url.openConnection();
con.setRequestMethod("GET");
con.setRequestProperty("Content-Type","text/html");
con.setConnectTimeout(5000);
con.setReadTimeout(5000);
} catch(Exception c) {
c.printStackTrace();
}
}
else {
}
int status = 0;
StringBuffer data = new StringBuffer();
try {
status = con.getResponseCode();
if(status > 299) {
System.out.println("error "+status);
System.out.println(con.getErrorStream());
return;
}
BufferedReader in = new BufferedReader(new
InputStreamReader(con.getInputStream()));
String str = null;
while((str=in.readLine()) != null) data.append(str);
System.out.println("here");
System.out.println(str);
in.close();
con.disconnect();
} catch(Exception c) {
c.printStackTrace();
}
});
Scene scene =new Scene(borderPane,350,180);
stage.setScene(scene);
stage.show();
}
public void setDesign(){
borderPane = new BorderPane();
borderPane.setPadding(new Insets(20,20,20,20));
vBox = new VBox(10);
vBox.setAlignment(Pos.CENTER);
HBox hBox1 =new HBox(5);
hBox1.setAlignment(Pos.CENTER);
HBox hBox2 =new HBox(5);
hBox2.setAlignment(Pos.CENTER);
Label label1= new Label("E-mail");
tName = new TextField();
tName.setMaxWidth(150);
hBox1.getChildren().addAll(label1,tName);
Label label2= new Label("Password");
tPassword = new TextField();
tPassword.setMaxWidth(150);
hBox2.getChildren().addAll(label2,tPassword);
comboBox = new ComboBox();
comboBox.getItems().add("Get");
comboBox.getItems().add("Post");
comboBox.getSelectionModel().selectFirst();
login = new Button("Login");
vBox.getChildren().addAll(hBox1,hBox2,comboBox,login);
borderPane.setTop(vBox);
}
public static void main(String[] args) {
launch();
}
}
I'm posting the entire codes so that everything is clear