CODEWITHSUNDEEP
javanetwork-programming
Veronica
Veronica

Reputation: 11

URLConnection class java.net.ConnectException: Connection refused: connect

I am programming on a system with client running Java Applet on one end and server on the other. Now I have the client and server on the same computer. But as a client, I cannot see the applet and I get error like below:

        java.net.ConnectException: Connection refused: connect
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.PlainSocketImpl.doConnect(Unknown Source)
    at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
    at java.net.PlainSocketImpl.connect(Unknown Source)
    at java.net.SocksSocketImpl.connect(Unknown Source)
    at java.net.Socket.connect(Unknown Source)
    at sun.net.NetworkClient.doConnect(Unknown Source)
    at sun.net.www.http.HttpClient.openServer(Unknown Source)
    at sun.net.www.http.HttpClient.openServer(Unknown Source)
    at sun.net.www.http.HttpClient.<init>(Unknown Source)
    at sun.net.www.http.HttpClient.New(Unknown Source)
    at sun.net.www.http.HttpClient.New(Unknown Source)
    at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(Unknown Source)
    at sun.net.www.protocol.http.HttpURLConnection.plainConnect(Unknown Source)
    at sun.net.www.protocol.http.HttpURLConnection.connect(Unknown Source)
    at sun.net.www.protocol.http.HttpURLConnection.getOutputStream(Unknown Source)
    at MainJApplet.init(MainJApplet.java:58)
    at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
java.net.ConnectException: Connection refused: connect
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.PlainSocketImpl.doConnect(Unknown Source)
    at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
    at java.net.PlainSocketImpl.connect(Unknown Source)
    at java.net.SocksSocketImpl.connect(Unknown Source)
    at java.net.Socket.connect(Unknown Source)
    at sun.net.NetworkClient.doConnect(Unknown Source)
    at sun.net.www.http.HttpClient.openServer(Unknown Source)
    at sun.net.www.http.HttpClient.openServer(Unknown Source)
    at sun.net.www.http.HttpClient.<init>(Unknown Source)
    at sun.net.www.http.HttpClient.New(Unknown Source)
    at sun.net.www.http.HttpClient.New(Unknown Source)
    at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(Unknown Source)
    at sun.net.www.protocol.http.HttpURLConnection.plainConnect(Unknown Source)
    at sun.net.www.protocol.http.HttpURLConnection.connect(Unknown Source)
    at sun.net.www.protocol.http.HttpURLConnection.getOutputStream(Unknown Source)
    at RequestServer.sendRequest(RequestServer.java:25)
    at createGUI.createEditingBar(createGUI.java:1313)
    at GUI.createAndShowGUI(GUI.java:813)
    at MainJApplet.init(MainJApplet.java:137)
    at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
java.net.ConnectException: Connection refused: connect
java.lang.NullPointerException
    at createGUI.createEditingBar(createGUI.java:1315)
    at GUI.createAndShowGUI(GUI.java:813)
    at MainJApplet.init(MainJApplet.java:137)
    at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Exception: java.lang.NullPointerException

Below is where the problem traced back:

URL url = new URL(ipAddr);
URLConnection connection = url.openConnection();

connection.setDoOutput(true);
OutputStreamWriter out = new OutputStreamWriter(connection.getOutputStream()); // exception happens

I checked http://localhost:8080/ and port conflict. I have turn off windows firewall and yet the problem exists. Can someone kindly point me some direction? Any advice would be great! Thanks ahead!

I apologize for the long code. The first is for client.

import javax.swing.*;
import java.awt.*;
import java.net.*;
import java.io.*;

public class MainJApplet extends JApplet {

    GUI gui = new GUI();
    Thread renewThread;

    public void init() {
        //pass parameters from url to applet
        String filePath = this.getParameter("FilePath");
        //temporary solution to bypass the new extention
        String userName = this.getParameter("UserName");
        String ipAddr = this.getParameter("IpAddress");
        String userLevel = this.getParameter("UserLevel");
        String ticket = this.getParameter("Ticket");
        String accessMode = this.getParameter("AccessMode"); //1-normal 2-shared 3-email

        //sharedTo will be get from the file path infor
        String sharedTo = this.getParameter("ShareTo");
        String type = this.getParameter("Type");

        gui.shareTo = sharedTo;
        gui.ticket = ticket; //this gui.ticket is used to varify email access, will be replaced

        String relativePath = "";
        try {
            //connect to servlet

            URL url = new URL(ipAddr);
            URLConnection connection = url.openConnection();

            connection.setDoOutput(true);
            OutputStreamWriter out = new OutputStreamWriter(connection.getOutputStream());
            //Passing NAME+FILE+TICKET+TYPE to server at the initialization stage
            out.write("IN");
            out.write(userName + "#");
            out.write(filePath + "#");
            out.write(ticket + "#");
            out.write(type + "#");
            out.close();

            //Wait for server response
            BufferedReader in = new BufferedReader(
                    new InputStreamReader(
                    connection.getInputStream()));

            String dcodedStr;
            StringBuffer decodedStringBuffer = new StringBuffer("");
            while ((dcodedStr = in.readLine()) != null) {
                decodedStringBuffer.append(dcodedStr);
            }

            String dStr = decodedStringBuffer.toString();
            in.close();

            if (dStr.equals("NOT_AUTHORIZED")) { //not passing authentication check
                JOptionPane.showMessageDialog(new JFrame(),
                        "Access Denied",
                        "Warning!",
                        JOptionPane.ERROR_MESSAGE);
                return;
            } else {//pass authentication check
                String[] initResp = dStr.split("#");
                gui.FID = initResp[0]; //file ID
                gui.EditMode = Boolean.parseBoolean(initResp[1]);
                gui.userLevel = 1; //temporary set all as normal user
                boolean firstOpen = Boolean.parseBoolean(initResp[2]);
                relativePath = initResp[3];
                if (initResp[4].trim().equals("normal")) {//owner
                    gui.accessMode = 1;
                } else {//shared user
                    gui.accessMode = 2;
                }
            }
        }catch(UnknownServiceException exp){
            exp.printStackTrace();
        }catch(IOException ex){
            ex.printStackTrace();
        }catch (Exception e) {
            e.printStackTrace();
        }
}

    public void destroy() {
        gui.check_upon_window_close();

        if (gui.is_new_drawing == 0) {
            //2010.9.29 workDir -> FID
            if (gui.EditMode) {
                RequestServer.canClose(gui.IpAddress, gui.user, gui.FID);
            } else {
                RequestServer.canCloseNoEdit(gui.IpAddress, gui.user, gui.FID);
            }
        }
        renewThread.stop();
    }
}

Upvotes: 1

Views: 6423

Answers (1)

Perception
Perception

Reputation: 80633

Based off your comments my guess is that your server is binding to the loopback address (127.0.0.1, aka localhost). You didn't post what the server software is, but change it's configuration so that it binds on 0.0.0.0 instead. That should fix your issue.

Upvotes: 1

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