Sending Message From One Client To Another Via Server?
Apr 2, 2014
I've just recently started playing around with network programming in Java, and I've come up with a simplistic server than can handle multiple clients and return the IP and port each one is connected to (or I'm under the impression that is so). What I've been requested to do as an exercise by one of the programming teachers at my high school (I'm not in a class, this is my own time) is send a message from one client to the other through the ServerSocket so that it may "watch" everything going on. I'm not sure how to go about this at all.
EDIT : now it never seems to go the the else or else if statements...
That is now the main problem. It never, ever, goes past the first if statement, no matter what it is.
EDIT : Okay, I haven't changed a line of code but suddenly not a single if statement is working. They just stopped. The client simply hangs and I can't type anything.
Server
public class Server implements Runnable {
Socket clientSocket;
Server(Socket clientSocket) {
this.clientSocket = clientSocket;
}
public static void main(String args[]) throws Exception {
ServerSocket ssock = new ServerSocket(3480);
System.out.println("Listening on port 3480");
[code]....
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Feb 25, 2014
I am trying to check the integrity in a Bank Transaction that the message sent to the server has not been modified by any malware in the client system. For this I am trying to read the message sent to the server at the client boundary so as that it enters the network as customer with customer intended values. So, firstly I need to check where to I need intercept the message within client boundary. Secondly, Can I intercept the message and read its contents using Java?
I want to check what my Online Banking Server( Leta Say Bank of America) receives if I ask to transfer amount $100 to Account A . I assume that there is a malware in client system that changes recipient to B,$10000. My aplicaion which I intend to design, shoudl inform the user that the integrity of the message is compromised and should give the option to the user to abort it. plan to track what message is being sent from client to server. This I want to achieve by reading the message from client at the last point before it leaves the client and enter the network.
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Apr 17, 2014
I have two programs that I'll post below, one is a Server and the other is a Client. The ChatServer runs once and many clients can run ChatClient from separate computers and talk together in their GUI's. The the client program comes with two buttons, one that's simulates the sending of a message to a single user ; "Send Message To User", and one that just generally sends a message ; "Send Message To All". Although now the Clients on the server seem to be able to selectively send messages to an individual by giving the recipient name, all the clients can see that message, which is not exact what I am aiming for. What I am going for is having the "Send Message To User" button click to send a message to the named user without all other users seeing the message.
The Server Program Code
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
[Code] ....
Now I have tried thing like having various input output streams and trying to connect those, but no luck. Tried fiddling with having the names arraylist directing the messages to one client versus all but that did not work out either. How I what I would need to do to go about doing this?
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Mar 4, 2015
I am creating a server that stores application updates. When the client connects the server send the update. The server is sending the file but the file is not complete, i.e, if the file is 317kb,its send 117kb. Below is the code I am using :
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
public class TestFileServer {
[Code] ....
What could the problem be?
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Feb 8, 2014
I'm creating ftp program which server will send not existing files on client to him.
There is method responsible for creating connection and sending list of files on client written by me.
Java Code:
[JAVA]//client method
public void enableClient() throws IOException, ClassNotFoundException {
System.out.print("Rozpoczęto działanie klienta");
strIP = jtfIP.getText();
intPort = Integer.parseInt(jtfNrPortu.getText());
clientPath= "C:/serweris/";
sck = new Socket(strIP, intPort);
[Code]....
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Sep 3, 2014
I have a problem on how to make my client to send the object to a server.
So I have one interface called "RMIInterface" and client "RMIClient" and server "RMIServer":
RMIInterface
interface RMIInterface {
public String getMessage(String text) throws RemoteException;
}
RMIClient
public class RMIClient {
[code]....
With this program I can connect to a Server with a Client, and print in Client console a message.But, how can I send message from a client to a server, and print that message in server console output?
make the simpliest example with sending a message to a server, edit inteface header code to public interface RMIInterface extends Remote, I forgot to add.
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Apr 21, 2014
I have to write a client and server class for a UDP protocol sending integer numbers by UDP packets. So far i have this;
Client Code:
import java.io.*;
import java.net.*;
class UDPClient {
public static void main(String args[]) throws Exception {
BufferedReader inFromUser =
new BufferedReader(new InputStreamReader(System.in));
[Code] ....
But i now need to change this so that:
The client;
1. Reads an integer from keyboard input and stores its value in a UDP packet.
// byte[] send = ByteBuffer.allocate(4).putInt(num).array(); ???
2. Sends the UDP packet to the server, on port number 1999;
3. Listens for UDP packets from the server (until it receives a packet with a non-positive number; see
step (b) below). While listening:
(a) Once it receives a UDP packet from the server, it subtracts 2 from the integer value num contained in it.
// int num = ByteBuffer.wrap(receive).getInt(); ???
(b) Checks the integer value num: if the value is greater than 0 (num>0) then the client stores it in a new UDP packet and sends the packet to the server; otherwise (num<=0) the client terminates.
The Server;
1. Listens on port 1999;
2. For each UDP packet it receives from a client:
(a) extracts the integer value n contained in it;
(b) decreases the value of n by 2;
(c) sends back to the client a UDP packet containing the new value of n.
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Jan 22, 2015
I want to send a message to a specific client in a server. This is my code and what I tried(I have only given you 3 classes in which I believe I have the problem).
TextClient:
import java.io.*;
import java.net.*;
import java.util.ArrayList;
import java.util.Scanner;
import java.util.concurrent.TimeUnit;
public class TextClient {
public TextClient() {
[Code] .....
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Jan 22, 2015
I want to send a message to a specific client in a server. This is my code and what I tried(I have only given you 3 classes in which I believe I have the problem).
TextClient:
import java.io.*;
import java.net.*;
import java.util.ArrayList;
import java.util.Scanner;
import java.util.concurrent.TimeUnit;
public class TextClient {
public TextClient() {
[Code]...
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Apr 22, 2014
I'm making a class in Android that takes a photo, list a photos in Listview, and then sends them all to server. I'm stuck on listing them. How to send them all to server.
Here is my code :
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.photo_upload);
Button picBtn = (Button) findViewById(R.id.buttonPhoto);
setBtnListenerOrDisable(picBtn, mTakePiconclickListener,
MediaStore.ACTION_IMAGE_CAPTURE);
[Code] ....
Executing this code i can take a first photo and place it into listview. But on second photo listing it crashes..
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Apr 26, 2014
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
public class M_serverApp extends javax.swing.JFrame implements Runnable {
[Code] ....
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Apr 26, 2014
Server:
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
public class M_serverApp extends javax.swing.JFrame implements Runnable {
ServerSocket server = null;
[Code]...
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Mar 3, 2015
I am a first-timer using J2EE and here on coderanch.com and wanted to make a Simple Email-like System which a Registered User can Send Message/Email to another Registered User. how to do it. I have already my register/login process done but I'm stuck on how to make the Email. And I have an sample Bootstrap for my UserInterface which I want to use.
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Oct 22, 2014
I am attempting to test a TCP Client and Server for an assignment I am doing in class. The goal here is to "test your client and Server applications by transferring (i) a file having 10,000+ lines (see supplied big-file1.txt having 12000+ lines), (ii) a file having 20,000+ lines (you may create one of your own from big-file1.txt, or obtain a large size file from the Google website at [URL] ...). Then, compute and display the total transfer time of the files at both of the sides separately (your choice in millisecond/second)."
I have created the TCPClient and TCPServer java classes, ran the server first and then the client, and using mathematical formulas to calculate the transfer time. Trouble is, I'm having trouble testing the client and server in the file area and not the area where I had to input a line, let the server print it, and then have the client eliminate the articles from the line. I need testing the file. Here is my code so far:
TCPClient:
package tcpclient;
import java.io.*;
import java.net.*;
public class TCPClient {
public static void main(String[] args) throws IOException{
// TODO Auto-generated method stub
String sentence;
[code] ....
How to fix the code so that the time in seconds does not output as 60 for both files and that the files go through the exchange?
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Apr 20, 2015
I have a program using Pipe line to exchange the infomation in the Client-Server model. Can I separate out main function and then put into Server main and Client main?
//PipeEchoServer
public class PipedEchoServer extends Thread {
PipedInputStream readPipe;
PipedOutputStream writePipe;
PipedEchoServer(PipedInputStream readPipe, PipedOutputStream writePipe){
this.readPipe = readPipe;
[code]....
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Feb 17, 2014
I have to develop a code in parallel which is implemented in sequential yet. How to add the server client relation in the program so that work can be divided into multiple clients.
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Apr 6, 2014
I want to ask that, when a server listen to A port and it accepts a request from a client then the server accepts the request using accept method,but how does the server get the info about the client like wat is the port no and ip address of the client,I read a answer regarding this that Server never gets the port no of client only the ip address and it connects to client using a connection stream but as far I know from networking, a device must have the ip address and port no of the device it wants to connect to.
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Jul 22, 2014
So we have a Client and Server. Client opens a socket to Server, server initiates new Thread to handle the communication with client. Is there a way to be singnalled when there is input on socket, so I don't have to use infinite while loop solution?
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Jun 9, 2014
I have gf 4.0.1 and swing client. I want to get EJB over SSL. I've set all certificates. However, I can get it work only when client and server are at the same host. What I see in tcpdump when they are at the same host:
10.0.17.2.48524 > 10.0.17.2.3820: Flags [P.], cksum 0x378f (incorrect -> 0xf2b6), seq 399:756, ack 1085, win 273, options [nop,nop,TS val 347297976 ecr 347297966], length 357
13:01:26.334898 IP (tos 0x0, ttl 64, id 51559, offset 0, flags [DF], proto TCP (6), length 665)
10.0.17.2.3820 > 10.0.17.2.48524: Flags [P.], cksum 0x388f (incorrect -> 0x626d), seq 1085:1698, ack 756, win 273, options [nop,nop,TS val 347297977 ecr 347297976], length 613
[code]...
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Mar 10, 2014
I am looking to run Server and Client from two different JButton.
When I click on start Server button, the server starts to run but I cannot click on start Client button to start the client. Here the code for server:
Java Code:
public void actionPerformed(ActionEvent e) {
Client c = new Client();
c.run();
} mh_sh_highlight_all('java');
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Dec 28, 2014
I've been trying to create a server/client chat program, but I keep running into areas where I'm not really sure how to work it. I've run into a wall where my client just sits and spins instead of working. URL.... I can work out the dynamic parts later, I just want to understand the meat and potatoes of reading from sockets and writing to sockets (and how to do both at the same time).
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May 2, 2015
I'm trying to build a SSL mutual authenticating private server. I'm not sure what keystores, truststores, or certificates I need to accomplish this. I made keystores for both programs using:
keytool -genkey -keyalg RSA -alias selfsigned -keystore keystore.jks -storepass password -validity 360 -keysize 2048
The server starts up fine, but when I run the client they both give errors.
Server code:
System.setProperty("javax.net.ssl.keyStore", "CLA.jks");
System.setProperty("javax.net.ssl.keyStorePassword", "password");
SSLServerSocketFactory sslServerSocketfactory = (SSLServerSocketFactory)SSLServerSocketFactory.getDefault();
SSLServerSocket sslServerSocket = (SSLServerSocket)sslServerSocketfactory.createServerSocket(9090);
SSLSocket s = (SSLSocket)sslServerSocket.accept();
BufferedReader in =
new BufferedReader(new InputStreamReader(s.getInputStream()));
[code]...
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Apr 6, 2014
It's an RMI program that has to be able to return the mean, mode and median of a set of numbers.It's composed of 4 classes; a client, an implementation class (with the math), an Interface, and a server class.
import java.rmi.NotBoundException;
import java.rmi.RMISecurityManager;
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;
import java.io.*;
[code]....
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Dec 6, 2014
So i wrote this text to try and create a simple chat program that does the following: Prepend names to messages, announce entrance and exit of chat, display user list, and share a whiteboard.So far the Server seems to be working but the Chat Client is throwing errors at me left and right..
CURRENT ERROR:
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.
C:Windowssystem32>cd..
C:Windows>cd..
C:>Usersjaydesktopchat
'Usersjaydesktopchat' is not recognized as an internal or external command,
operable program or batch file.
[code]....
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Feb 26, 2014
I have a question: I have a Java/JSP/JavaScript project that access back end Oracle database, and provide interaction through tomcat. After we deployed our project, I found one button does not generate necessary warning message from server, but when I deployed and tested our project on local PC, it does generate correct warning message. I am using the same IE, same tomcat version, and I am sure my container is pointing to the same database, and I am sure I using same version of project code by checking with GIT.
Here is the button that I click:
<a target="frmMain" href="RealignServlet?button=REALIGNMENT" title="Procedure Alignment">Align</a><br>
And here is part of the code of RealignServlet:
public class RealignServlet extends SiapBaseServlet {
private static final long serialVersionUID = 1L;
private static final Logger logger = AppLogger.getLogger(RealignServlet.class.getName());
private static final String PROC_QUERY_JSP = "ProcQuery.jsp";
private static final String REALIGN = "REALIGNMENT";
[Code] .....
Our problem is server could not generate alignMsg. But we can get it on local deployed project.
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Jun 14, 2014
What is the best way to send an arrayList from the server to the client? ObjectInputStream and ObjectOutputStream?
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