I want to inject data directly to ElasticSearch to perform some performance tests. My first thought was to create JSON file for each document and import the files into ElasticSearch, but it will take too long. I tested 110K files and it took 18 min only to create the files, I need 55M documents - that's 500 times what I tested. Quick calculation: it will take 150 hours, or 6.25 days, that's too long.
Second option is stop when I have the JSON in a stirng and inject the string into ElasticSearch using Logstash. But, I get an exception:
2019-12-16 13:49:27,240 | Timer-0 | ERROR | search-injector | c.n.es.injector.output.SocketOutput | SocketOutput::output:
java.net.SocketException: Software caused connection abort: socket write error
at java.net.SocketOutputStream.socketWrite0(Native Method)
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:111)
at java.net.SocketOutputStream.write(SocketOutputStream.java:134)
at java.io.DataOutputStream.writeBytes(DataOutputStream.java:276)
at com.beniregev.es.injector.output.SocketOutput.output(SocketOutput.java:39)
at com.beniregev.es.injector.policies.UpdateOutputHandlers.run(UpdateOutputHandlers.java:60)
at java.util.TimerThread.mainLoop(Timer.java:555)
at java.util.TimerThread.run(Timer.java:505)
ElasticSearch is running on localhost port 9200, Logstash is running on localhost port 9600.
My SocketOutput.java
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;
public class SocketOutput implements OutputHandler {
private static final Logger log = LoggerFactory.getLogger(SocketOutput.class);
public static final String CLI_OPTION = "socket";
#Value("${socket.hostname}")
private String hostname;
#Value("${socket.port}")
private int port;
Socket clientSocket;
public boolean open() {
try {
clientSocket = new Socket(hostname, port);
} catch (IOException ioe) {
log.error("", ioe);
return false;
}
return true;
}
#Override
public void output(String data) {
DataOutputStream outToServer = null;
try {
outToServer = new DataOutputStream(clientSocket.getOutputStream());
outToServer.writeBytes( data );
} catch (IOException ioe) {
log.error("", ioe);
}
}
}
logstash-simple.conf
# Simple Logstash configuration for creating a simple
# Stdin -> Logstash -> Elasticsearch pipeline.
input { stdin { } }
output {
elasticsearch {
hosts => ["http://localhost:9200"]
index => "%{[#metadata][beat]}-%{[#metadata][version]}-%{+YYYY.MM.dd}"
}
stdout { codec => rubydebug }
}
I am running Logstash with this command: bin/logstash.bat -f config/logstash-simple.conf
The JSON string is created and is valid, the Socket gets correct parameters values (hostname="localhost" and port=9600).
I will appreciate any assistance.
There are several layers for the solution, starting with creating and using the correct index in Elastic Search using Kibana Manager, then configuring Logstash properly, and last is using a JSON string instead of the file.
Creating an index is not the issue of this question, so I will not get into it.
Logstash.conf (configuration file):
#################################################
# Stdin -> Logstash -> Elastic Search pipeline.
#################################################
input {
stdin{}
tcp{
host => "localhost"
port => 9600
codec => json
}
}
filter
{
mutate
{
remove_field => ["host", "#version", "#timestamp", "port", "tags", "level", "logger_name", "themessage", "mensage", "spring.application.name", "level_value", "thread_name"]
}
}
output {
stdout{ codec => rubydebug }
elasticsearch{
hosts => ["localhost:9200"]
index => ["my-index"]
}
}
NOTE: in index you enter the name of the index you created and will use.
Running Logstash with the configuration file: bin/logstash.bat -f config/logstash-simple.conf
Outputing the string to Logstash in Java:
package com.beniregev.injector.output;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;
public class SocketOutput implements OutputHandler {
private static final Logger log = LoggerFactory.getLogger(SocketOutput.class);
public static final String CLI_OPTION = "socket";
private int outputIndex = 0;
#Value("${socket.hostname}")
private String hostname;
#Value("${socket.port}")
private int port;
Socket clientSocket;
public boolean open() {
try {
clientSocket = new Socket(hostname, port);
} catch (IOException ioe) {
log.error("", ioe);
return false;
}
return true;
}
#Override
public void output(String data) {
DataOutputStream outToServer = null;
try {
outToServer = new DataOutputStream(clientSocket.getOutputStream());
outToServer.writeBytes( data );
outputIndex++;
} catch (IOException ioe) {
log.error("", ioe);
}
System.out.println("Wrote segment " + outputIndex + " to socket");
}
}
host and port are to Logstash, by default port=9600.
This resolved the problem for me.
I am trying to read some packets from a port 2020 in my server. I have run tcpdump -r eth1 port 2020 and can find that udp packets are coming into the port. Following is the screenshot :
But when i try to read those packets from the java code, i do not get any data. Following is my java code :
package packetreceiver;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.SocketException;
import java.net.UnknownHostException;
import main.Main;
import propertyfilereader.PropertyFileReader;
import org.apache.log4j.Logger;
import com.sun.jmx.snmp.SnmpMessage;
import alarmprocessor.AlarmProcessor;
public class UDPPacketReceiver extends Thread {
private DatagramSocket socket = null;
private Logger logger = Logger.getLogger(UDPPacketReceiver.class);
public boolean dynamicKey = false;
private UDPPacketReceiver() {
try {
logger.debug(" port : " + Main.orgPort);
logger.debug(" ip : " + Main.orgBindIPStr);
logger.debug("creating socket");
socket = new DatagramSocket(null);
//socket = new DatagramSocket(38567);
InetSocketAddress address = new InetSocketAddress(2020);
socket.bind(address);
logger.debug("Receiver Socket created successfully");
} catch (Exception e) {
logger.fatal("Exception at creating socket ", e);
logger.fatal("Exiting successfully ");
System.exit(0);
}
this.running = true;
}
static UDPPacketReceiver instance = null;
public static UDPPacketReceiver getInstance() {
if (instance == null) {
createInstance();
}
return instance;
}
boolean running = false;
private static synchronized UDPPacketReceiver createInstance() {
if (instance == null) {
instance = new UDPPacketReceiver();
}
return instance;
}
public void run() {
byte[] data = new byte[2048];
DatagramPacket packet = new DatagramPacket(data, data.length);
while (this.running) {
try {
logger.debug("waiting for received data");
this.socket.receive(packet);
int length = packet.getLength();
logger.debug("length:"+length);
logger.debug("data:"+new String(packet.getData()));
} catch (Exception e) {
if ((this.socket == null) || (this.socket.isClosed())) {
this.running = false;
} else {
this.logger.fatal("Error in receiving UDP packet:", e);
}
}
}
}
public void shutdown() {
this.running = false;
try {
if ((this.socket != null) && (!this.socket.isClosed())) {
this.socket.close();
}
} catch (Exception localException) {
}
this.socket = null;
}
}
I have searched in stackeoverflow and other posts but could not find any solution. Can you please help me.
Regards,
Tanvir
Check with the netstat command to see whether your application is actually bound to the correct IP/interface:
> sudo netstat -tunlp | grep 2020
works in linux.
You can also change this line:
InetSocketAddress address = new InetSocketAddress(172.22.49.116, 2020);
I am planning to do a java onvif application. I have created a new project and generated sources from devicemgmt.wsdl.Also generated the classes from remote discovery.wsdl.
How can I discover a device in a network using theses generated classes?
Thanks for any help.
devicemgmt.wsdl is not related to discovery process, the ONVIF discovery process is based on http://specs.xmlsoap.org/ws/2005/04/discovery it use SOAP over UDP.
If you are using apache-cxf, this can be achieve using
org.apache.cxf.ws.discovery.WSDiscoveryClient
A simple sample code could be :
import java.util.List;
import javax.xml.ws.EndpointReference;
import org.apache.cxf.ws.discovery.WSDiscoveryClient;
public class Main
{
public static void main(String[] args)
{
WSDiscoveryClient client = new WSDiscoveryClient();
client.setVersion10(); // use WS-discovery 1.0
client.setDefaultProbeTimeout(1000); // timeout 1s
System.out.println("Probe:" + client.getAddress());
List<EndpointReference> references = client.probe();
System.out.println("Nb answsers:" + references.size());
for (EndpointReference ref : references)
{
System.out.println(ref.toString());
}
}
}
I had the same problem, CXF is simply to big, please check my approach: JavaWsDiscovery at https://github.com/thhart/javaWsDiscovery.
It uses a simple network probe as suggested by Onvif standards to be able to identify any devices on your local network, following line will return you all available devices:
final Collection urls = DeviceDiscovery.discoverWsDevicesAsUrls("^http$", ".onvif.");
Simple and complete example pure Java
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.net.SocketTimeoutException;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.List;
/**
*
* #author Ronald
*/
public class TestDiscoveryPureJava {
public static void main(String cor[]) throws SocketException{
discoverWsDevices();
}
public static void discoverWsDevices() throws SocketException {
final int WS_DISCOVERY_PORT = 3702;
final String WS_DISCOVERY_ADDRESS_IPv4 = "239.255.255.250";
Thread thread = new Thread() {
#Override
public void run() {
final String probe = "<?xml version=\"1.0\" encoding=\"UTF-8\"?><s:Envelope xmlns:s=\"http://www.w3.org/2003/05/soap-envelope\" xmlns:a=\"http://schemas.xmlsoap.org/ws/2004/08/addressing\">\n" +
" <s:Header>\n" +
" <a:Action s:mustUnderstand=\"1\">http://schemas.xmlsoap.org/ws/2005/04/discovery/Probe</a:Action>\n" +
" <a:MessageID>uuid:f0ded492-301a-4891-882b-cb2d7cac2e45</a:MessageID>\n" +
" <a:ReplyTo>\n" +
" <a:Address>http://schemas.xmlsoap.org/ws/2004/08/addressing/role/anonymous</a:Address>\n" +
" </a:ReplyTo>\n" +
" <a:To s:mustUnderstand=\"1\">urn:schemas-xmlsoap-org:ws:2005:04:discovery</a:To>\n" +
" </s:Header>\n" +
" <s:Body>\n" +
" <Probe xmlns=\"http://schemas.xmlsoap.org/ws/2005/04/discovery\">\n" +
" <d:Types xmlns:d=\"http://schemas.xmlsoap.org/ws/2005/04/discovery\" xmlns:dp0=\"http://www.onvif.org/ver10/network/wsdl\">dp0:Device</d:Types>\n" +
" </Probe>\n" +
" </s:Body>\n" +
"</s:Envelope>";
DatagramSocket datagramSocket = null;
try {
datagramSocket = new DatagramSocket();
datagramSocket.setBroadcast(true);
datagramSocket.setSoTimeout(9000);
} catch (SocketException e) {
System.out.println( "In discoverWsDevices datagram socket exception" + datagramSocket);
e.printStackTrace();
}
byte[] soapMessageByteArray = probe.getBytes();
DatagramPacket datagramPacketSend = null;
try {
datagramPacketSend = new DatagramPacket(
soapMessageByteArray,
soapMessageByteArray.length,
InetAddress.getByName(WS_DISCOVERY_ADDRESS_IPv4),
WS_DISCOVERY_PORT);
} catch (UnknownHostException e) {
System.out.println("Unknown host in send packet");
e.printStackTrace();
}
try {
System.out.println("Send package");
datagramSocket.send(datagramPacketSend);
System.out.println("package sent");
} catch (IOException e) {
System.out.println("In discoverWsDevices datagram socket IOException send " + datagramSocket);
e.printStackTrace();
}
System.out.println("Sending data");
System.out.println(datagramPacketSend.getAddress().getHostName()+":"+WS_DISCOVERY_PORT);
List<ByteArrayInputStream> probeMatches = new ArrayList<>();
while (true) {
byte[] responseMessageByteArray = new byte[9000];
DatagramPacket datagramPacketRecieve = new DatagramPacket(responseMessageByteArray,responseMessageByteArray.length);
try {
System.out.println("Waiting response...");
datagramSocket.receive(datagramPacketRecieve);
} catch (SocketTimeoutException e) {
datagramSocket.close();
System.out.println("In discoverWsDevices datagram socket timeout exception");
break;
} catch (IOException e) {
System.out.println("In discoverWsDevices datagram socket ioexception");
e.printStackTrace();
break;
}
probeMatches.add(new ByteArrayInputStream(datagramPacketRecieve.getData(), 0, datagramPacketRecieve.getLength()));
}
for (ByteArrayInputStream input : probeMatches) {
byte[] bytes = new byte[input.available()];
input.read(bytes, 0, input.available());
String stream = new String(bytes);
System.out.println("stream" + stream);
}
}
};
thread.start();
}
}
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Reinstating this question with a bounty! I need an example that stays online, like a real instant messenger! It needs to always be ready to receive or send a message to an arbitrary address over an arbitrary port, using TCP. The program must not quit after sending/receiving a message.
Bounty goes to whoever can give the best example of a real, usable instant messenger.
Looking online, all resources I found are either useless tutorials, dead threads, dead tutorials, ancient examples, or tell the programmer to use external APIs. How can I create a basic instant messenger from the ground up, only using Java SE?
There must be a way to do this, and some sample code would be appreciated. It only needs to perform the simplest tasks: Check if a compatible client is online on another computer (IP will be provided by the user) and send a TCP packet to that client, which will receive and display its contents.
When this question was first asked and answered back in 2011, it was simply "Looking online, all resources I found are either useless
tutorials, dead threads, or tell the programmer to use external
APIs.". The provided links below met the criteria at the time. Further discussion follows in the comments.
First few Google results for "java socket chat":
http://cs.lmu.edu/~ray/notes/javanetexamples/
simple chatting program in java usings socket class
http://pirate.shu.edu/~wachsmut/Teaching/CSAS2214/Virtual/Lectures/chat-client-server.html
http://www.cise.ufl.edu/~amyles/tutorials/tcpchat/
http://ashishmyles.com/tutorials/tcpchat/index.html
Internet Archive link to fix missing Java source file downloads: https://web.archive.org/web/20150623102646/http://ashishmyles.com/tutorials/tcpchat/index.html
Or from "java 8 chat client":
https://gist.github.com/alex-zykov/b4052e3c1b6891081897
Many, many results following in the search. Pick one that suits your needs. You can even modify the Google search to only show results from the past year, if you wish.
I've done this when I was learning Java, something around 10 years ago. It works:
Constantes.java:
package jsc;
public interface Constantes {
public static final String MULTICAST_IP = "224.0.0.1";
public static final int MULTICAST_PORTA = 3333;
public static final String SEPARADOR = "[>>>]";
public static final int TAMANHO_MENSAGEM = 1024;
public static final long ESPERA = 3000;
public static final String ESTOUONLINE = "EstouOnline";
public static final String DESCONECTANDO = "Desconectando";
public static final String PRIVADO = "Privado";
}
ControladorThread.java
package jsc;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.InetAddress;
import java.net.MulticastSocket;
import java.net.UnknownHostException;
import java.util.Date;
import java.util.Iterator;
import java.util.StringTokenizer;
import java.util.Vector;
public class ControladorThread extends Thread implements Constantes{
private MulticastSocket mcSocket;
private Main main;
private Vector<Usuario> listaUsuarios; // lista de usuários ativos
public ControladorThread(Main main){
super("ReceptoraThread_" + main.getNick());
listaUsuarios = new Vector<Usuario>();
listaUsuarios.add(new Usuario(main.getNick(), new Date().getTime()));
this.main = main;
try{
mcSocket = new MulticastSocket(MULTICAST_PORTA);
mcSocket.joinGroup(InetAddress.getByName(MULTICAST_IP));
} catch(IOException e){
e.printStackTrace();
}
}
public void run(){
while(true){
try{
byte[] buffer = receberPacote();
processar(buffer);
removerUsuariosOciosos();
atualizarListaUsuarios();
} catch(IOException e){
e.printStackTrace();
}
}
}
public byte [] receberPacote() throws IOException{
byte[] buffer = new byte[TAMANHO_MENSAGEM];
DatagramPacket pacote = new DatagramPacket(buffer, buffer.length);
mcSocket.receive(pacote);
return buffer;
}
public void processar(byte[] buffer){
String mensagem = new String(buffer);
mensagem = mensagem.trim();
StringTokenizer tokens = new StringTokenizer(mensagem, SEPARADOR);
String t1 = tokens.nextToken();
String t2 = tokens.nextToken();
if(t1.equals(ESTOUONLINE))
atualizarEstadoUsuario(t2);
else if(t1.equals(DESCONECTANDO))
desconectarUsuario(t2);
else if(t1.equals(PRIVADO)){
String t3 = tokens.nextToken();
String t4 = tokens.nextToken();
if(t3.equals(main.getNick())){
receberMensagemPrivada(t2, t4);
}
}
else
main.setTextoEntrada(t1 + " diz: " + t2);
}
public void receberMensagemPrivada(String deUsuario, String mensagem){
main.abrirChatPrivado(main.getNick(), deUsuario, mensagem);
}
public boolean atualizarEstadoUsuario(String nomeUsuario){
int pos;
for(Iterator i = listaUsuarios.iterator(); i.hasNext(); ){
Usuario uAux = (Usuario) i.next();
if(uAux.getNome().equals(nomeUsuario)){
pos = listaUsuarios.indexOf(uAux);
listaUsuarios.remove(uAux);
uAux.setTempoInicio(new Date().getTime());
listaUsuarios.add(pos, uAux);
return true;
}
}
listaUsuarios.add(new Usuario(nomeUsuario, new Date().getTime()));
return false;
}
public void removerUsuariosOciosos(){
Usuario usuario = null;
for(Iterator i = listaUsuarios.iterator(); i.hasNext(); ){
usuario = (Usuario) i.next();
if(new Date().getTime() - usuario.getTempoInicio() > ESPERA){
desconectarUsuario(usuario.getNome());
i = listaUsuarios.iterator();
}
}
}
public void desconectarUsuario(String nomeUsuario){
for(Iterator i = listaUsuarios.iterator(); i.hasNext(); ){
Usuario uAux = (Usuario) i.next();
if(uAux.getNome().equals(nomeUsuario)){
i.remove();
break;
}
}
}
public void atualizarListaUsuarios(){
Vector<String> sVector = new Vector<String>();
Usuario uAux = null;
System.out.println("\nOnline: ");
for(Iterator i = listaUsuarios.iterator(); i.hasNext(); ){
uAux = (Usuario) i.next();
System.out.print( uAux.getNome() + " ");
sVector.add(uAux.getNome());
}
main.setUsuariosOnline(sVector);
}
private class Usuario{
private String nome;
private long tempoInicio;
public Usuario(){}
public Usuario(String nome, long tempoInicio){
this.nome = nome;
this.tempoInicio = tempoInicio;
}
public String getNome() {
return nome;
}
public void setNome(String nome) {
this.nome = nome;
}
public long getTempoInicio() {
return tempoInicio;
}
public void setTempoInicio(long tempoInicio) {
this.tempoInicio = tempoInicio;
}
}
public void sair(){
try {
mcSocket.leaveGroup(InetAddress.getByName(MULTICAST_IP));
mcSocket.close();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
EstouOnlineThread.java
package jsc;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.InetAddress;
import java.net.MulticastSocket;
public class EstouOnlineThread extends Thread implements Constantes{
private MulticastSocket mcSocket;
private String nick;
private byte[] buffer;
public EstouOnlineThread(String nick){
super("EstouOnlineThread_" + nick);
this.nick = nick;
try {
mcSocket = new MulticastSocket();
} catch(IOException e) {
e.printStackTrace();
}
}
public void run(){
String saida = ESTOUONLINE + SEPARADOR + nick;
buffer = saida.getBytes();
while(true){
try{
DatagramPacket estouOnline = new DatagramPacket(buffer, buffer.length, InetAddress.getByName(MULTICAST_IP), MULTICAST_PORTA);
mcSocket.send(estouOnline);
System.out.println(saida);
sleep(ESPERA);
}
catch(InterruptedException e){
e.printStackTrace();
}
catch(IOException e){
e.printStackTrace();
}
}
}
}
MensagemPrivadaFrame.java
package jsc;
import java.awt.BorderLayout;
import java.awt.Frame;
import java.awt.TextArea;
import java.awt.TextField;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.InetAddress;
import java.net.MulticastSocket;
import java.net.UnknownHostException;
public class MensagemPrivadaFrame extends Frame implements Constantes{
private static final long serialVersionUID = 1L;
private TextArea entrada;
private TextField saida;
private String nomeJanela;
private String nick;
private String paraUsuario;
private MulticastSocket mcSocket;
private ActionListener saidaListener;
private WindowAdapter frameListener;
private boolean estouVivo; // indica que a janela ainda está ativa
public MensagemPrivadaFrame(String nick, String paraUsuario){
super("JSC - Chat com " + paraUsuario);
setIconImage(Toolkit.getDefaultToolkit().getImage("icone.4"));
this.nick = nick;
this.paraUsuario = paraUsuario;
this.nomeJanela = nick + paraUsuario;
try {
mcSocket = new MulticastSocket();
} catch (IOException e) {
e.printStackTrace();
}
iniciarComponentes();
estouVivo = true;
}
public void setNomeJanela(String nomeJanela){
this.nomeJanela = nomeJanela;
}
public String getNomeJanela(){
return nomeJanela;
}
public String getNick() {
return nick;
}
public void setNick(String nick) {
this.nick = nick;
}
public boolean estouVivo(){
return estouVivo;
}
public void iniciarComponentes(){
saidaListener = new ActionListener(){
public void actionPerformed(ActionEvent e){
TextField origem = (TextField) e.getSource();
enviarMensagem(origem.getText());
entrada.append("\n(" + nick + " diz) " + origem.getText());
origem.setText("");
}
};
frameListener = new WindowAdapter(){
public void windowClosing(WindowEvent e){
estouVivo = false;
dispose();
}
};
entrada = new TextArea("[JSC] Bate papo privado entre " + nick + " e " + paraUsuario + "\n");
entrada.setEditable(false);
saida = new TextField();
saida.addActionListener(saidaListener);
addWindowListener(frameListener);
setLayout(new BorderLayout());
int x = (int) (Math.random() * 500);
int y = (int) (Math.random() * 500);
setBounds(x, y, 400, 300);
System.out.println(x + " " + y);
add("Center", entrada);
add("South", saida);
setVisible(true);
saida.requestFocus();
}
public void setTextoEntrada(String texto){
entrada.append("\n" + texto);
entrada.setCaretPosition(entrada.getText().length());
}
public void enviarMensagem(String mensagem){
try{
mensagem = PRIVADO + SEPARADOR + nick + SEPARADOR + paraUsuario + SEPARADOR + mensagem;
byte[] bMensagem = mensagem.getBytes();
DatagramPacket pacote = new DatagramPacket(bMensagem, bMensagem.length, InetAddress.getByName(MULTICAST_IP), MULTICAST_PORTA);
mcSocket.send(pacote);
}
catch(UnknownHostException e){
e.printStackTrace();
}
catch(IOException e){
e.printStackTrace();
}
}
}
Main.java
package jsc;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Frame;
import java.awt.ScrollPane;
import java.awt.TextArea;
import java.awt.TextField;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.InetAddress;
import java.net.MulticastSocket;
import java.net.UnknownHostException;
import java.util.Iterator;
import java.util.Vector;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JOptionPane;
public class Main extends Frame implements Constantes{
private static final long serialVersionUID = 1L;
private TextArea entrada;
private TextField saida;
private JList usuariosOnline;
private ScrollPane usuariosOnlineScroll;
private WindowAdapter mainListener;
private ActionListener saidaListener;
private MouseAdapter listListener;
private MulticastSocket mcSocket; // soquete para multicasting
private Vector<String> listaUsuariosOnline; // lista com os nomes de usuários online
private Vector<MensagemPrivadaFrame> listaJanelasAbertas; // janelas de conversação privadas abertas
private String nick; // nome do usuário no chat
public void setNick(String nick){
this.nick = nick;
}
public String getNick(){
return nick;
}
public Main(String nick){
super("Java Socket Chat [" + nick + "]");
setIconImage(Toolkit.getDefaultToolkit().getImage("icone.1"));
this.nick = nick;
listaUsuariosOnline = new Vector<String>();
listaUsuariosOnline.add(nick);
listaJanelasAbertas = new Vector<MensagemPrivadaFrame>();
try{
mcSocket = new MulticastSocket();
}
catch(IOException e){
e.printStackTrace();
}
iniciarComponentes();
new EstouOnlineThread(nick).start();
new ControladorThread(this).start();
}
public void iniciarComponentes(){
mainListener = new WindowAdapter(){
public void windowClosing(WindowEvent e){
sair();
}
};
saidaListener = new ActionListener(){
public void actionPerformed(ActionEvent e){
TextField origem = (TextField) e.getSource();
enviarMensagem(origem.getText());
origem.setText("");
}
};
listListener = new MouseAdapter(){
public void mouseClicked(MouseEvent e){
if( e.getClickCount() >= 2 ){
// abrir a janela para mensagens privadas e passar o id do usuário
JList jlAux = (JList) e.getSource();
String paraUsuario = (String) jlAux.getSelectedValue();
abrirChatPrivado(nick, paraUsuario, null);
}
}
};
usuariosOnline = new JList(listaUsuariosOnline);
usuariosOnline.setSize(new Dimension(60, 280));
usuariosOnlineScroll = new ScrollPane();
usuariosOnlineScroll.add(usuariosOnline);
entrada = new TextArea("Olá " + nick);
entrada.setEditable(false);
entrada.setSize(300,280);
saida = new TextField();
saida.addActionListener(saidaListener);
usuariosOnline.addMouseListener(listListener);
usuariosOnline.setMinimumSize(new Dimension(60, 250));
addWindowListener(mainListener);
setSize(400, 300);
setLayout(new BorderLayout());
add("North", new JLabel("Java Socket ChatO"));
add("Center", entrada);
add("South", saida);
add("East", usuariosOnlineScroll);
setVisible(true);
requestFocus();
}
public void enviarMensagem(String mensagem){
try{
mensagem = nick + SEPARADOR + mensagem;
byte[] bMensagem = mensagem.getBytes();
DatagramPacket pacote = new DatagramPacket(bMensagem, bMensagem.length, InetAddress.getByName(MULTICAST_IP), MULTICAST_PORTA);
mcSocket.send(pacote);
}
catch(UnknownHostException e){
e.printStackTrace();
}
catch(IOException e){
e.printStackTrace();
}
}
private void desconectando(){
try{
String mensagem = "Desconectando" + SEPARADOR + nick;
byte[] bMensagem = mensagem.getBytes();
DatagramPacket pacote = new DatagramPacket(bMensagem, bMensagem.length, InetAddress.getByName(MULTICAST_IP), MULTICAST_PORTA);
mcSocket.send(pacote);
}
catch(UnknownHostException e){
e.printStackTrace();
}
catch(IOException e){
e.printStackTrace();
}
}
public void abrirChatPrivado(String nick, String paraUsuario, String mensagem){
removerJanelasInativas();
if(nick.equals(paraUsuario)){
JOptionPane.showMessageDialog(null, "Você não pode abrir um janela de conversação para você mesmo!", "Burro!", JOptionPane.ERROR_MESSAGE);
return;
}
String nome = nick + paraUsuario;
MensagemPrivadaFrame janela = null;
for(Iterator i = listaJanelasAbertas.iterator(); i.hasNext();){
janela = (MensagemPrivadaFrame) i.next();
if(nome.equals(janela.getNomeJanela())){
System.out.println(nick + " - " + janela.getNomeJanela() + " - " + janela.toString());
janela.setTextoEntrada("(" + paraUsuario + " diz) " + mensagem);
//janela.requestFocus();
return;
}
}
janela = new MensagemPrivadaFrame(nick, paraUsuario);
if(mensagem != null)
janela.setTextoEntrada("(" + paraUsuario + " diz) " + mensagem);
listaJanelasAbertas.add(janela);
//janela.requestFocus();
}
public void removerJanelasInativas(){
MensagemPrivadaFrame janela = null;
for(Iterator i = listaJanelasAbertas.iterator(); i.hasNext(); ){
janela = (MensagemPrivadaFrame) i.next();
if( !janela.estouVivo()){
i.remove();
}
}
}
public void setTextoEntrada(String texto){
entrada.append("\n" + texto);
entrada.setCaretPosition(entrada.getText().length());
}
public void setUsuariosOnline(Vector<String> listaUsuariosOnline){
usuariosOnline.setListData(listaUsuariosOnline);
}
public void sair(){
desconectando();
dispose();
System.exit(0);
}
public static void main(String args[]){
String nick = JOptionPane.showInputDialog("Digite seu nome (max. 20 caracteres): ");
if(nick != null && !nick.equals("")){
if(nick.length() > 20)
nick = nick.substring(0, 20);
new Main(nick);
}
else
JOptionPane.showMessageDialog(null, "É necessário informar um nome para entrar no bate-papo");
//System.exit(0);
}
}
Nowadays I'm not proud of the code, but it really works.
Edit:
As some have suggested, I've made some code improvements (refactoring) and post the project on GitHub: https://github.com/jaumzera/javasocketchat
Hm, I was tempted to direct you to a java implementation of a server implementing imap protocol (eg. gavamail). But this, of cources, might also qualify as "old" code and for sure would kill your expectation (for being a non-standard solution). Nevertheless it is a proper reference fulfilling your (terse) specification.
What do we have?
We need a solution that should be in java.
It must implement an basic instant messaging system.
The later is problematic as it covers a really broad range of functionality. But "basic" seem to allow for a minimum solution.
So what is a minimum instant messaging system? Let's try with the following:
a client that is posting and retrieving messages.
a server that is storing posted messages for (later) retrieval
We also would need a policy of how a client would identify a proper server. Most trivial solution for the later aspect is using a "central" server with a well-known address. For more complex cases we would need to have the server and/or client functionality distributed across several instances and devise a scheme or policy for identifying the proper instance(s) for communication.
We leave out more complex semantics like having different users or messages being related to a system of categories or tags.
Now, we are down to having two components:
A server implementing two entry points:
POST_MESSAGE
receive a mesage form a client and store it for later retrieval
This immediatley is asking the question of where to store such messages (in a database or filesystem for persistency or simply within memory for a "messages live as long as the server is up" semantics)
LOOKUP_MESSAGE
select a suitable message from the stored ones (preferrably an unread one) and return to caller.
This could also return a set of messages (but think of restricting such set for cases where a caller has a severe backlog of messages)
It might be necessary to keep track of the messages already having been read, either by marking the messages or by maintaining seen status at the client. This could even be as simple as keeping time or ordinal of last message seen and send this information along with the LOOKUP_MESSAGE request.
A client needs to interact with a user on one hand and the service on the other hand.
It will take gat a new message from the user (likely on explicit request (e.g. send button) and call the POST_MESSAGE service at the related server.
It also will (likely regularly, could also be on explicit request (e.g. user is starting client)) poll the server for new messages. (Alternatively, you could devise a separate notification service that is used by the server to notify the client of new messages. What suits your "needs" is beyond your question.)
That's it.
So any example of a TCP based client/server application will form a perfect starting point for a straight implementation.
I should also mention that you could cut the specification logic within the client and delegate user interaction to a standard browser and implement the client application logic into a (web-)server instance (together or separate from the server part). Nevertheless, you still will have both (client/server) logical functionality according to above minimum specification.
Another aspect you should be aware of:
With some comments you mentioned "host" and "guest" attributions available in current messenger examples. This actually is a logical structure of a tagging system provided with those messengers. The messages are still sent from a client to a server and then being retrieved by other clients. Whether a client can see a message is determined by the client being eligible to the specific tag. E.g posting a message to a contact from yours (user b) just tags the message with the tag "for_user_b" and as such it is only visible to the poster and anybody that is also allowed to read "for_user_b" tag messages (user b in our example). So, please be aware that the logical structure of a messaging system is determined by the access and distribution policy and not by the physical distribution structure!
I am not even sure if this question is still being used or what but I liked the task and I thought:
why not?
Here is my implementation, as simple as it gets but without forgetting fundamental parts.
Written in pure Java, makes use of, among the rest, Sockets, Threads and SynchronizedList:
SimpleChat.java (Main)
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class SimpleChat {
private static boolean isRunning = true;
private static Sender sender;
private static Receiver receiver;
public static void main(String[] args) throws IOException {
if(args.length < 3){
showUsage();
}
try {
receiver = new Receiver(Integer.parseInt(args[1]));
sender = new Sender(args[0], args[2], Integer.parseInt(args[3]));
} catch (InterruptedException e) {
showUsage();
}
// Read user input
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println("Chat started. Type '\\exit' to quit.");
while(isRunning) {
String input = br.readLine();
if(input.equals("\\exit")){
receiver.stop();
sender.stop();
isRunning = false;
} else {
sender.sendMessage(input);
}
}
}
static void showUsage(){
System.out.println("Usage: java SimpleChat.java listening_port target_IP target_port");
System.exit(1);
}
}
Receiver.java
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
public class Receiver {
private boolean isRunning = true;
public Receiver(int listeningPort) throws IOException {
Runnable receiverT = new Runnable() {
public void run() {
ServerSocket serverSocket;
try {
serverSocket = new ServerSocket(listeningPort);
Socket clientSocket = serverSocket.accept();
BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
while(isRunning) {
try {
System.out.println(in.readLine());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
};
new Thread(receiverT).start();
}
public void stop(){
isRunning = false;
}
}
Sender.java
import java.io.IOException;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
public class Sender {
private boolean isRunning = true;
private volatile List<String> msgs;
public Sender(String username, String targetIP, int targetPort) throws InterruptedException, UnknownHostException, IOException {
msgs = Collections.synchronizedList(new ArrayList<String>());
Runnable senderT = new Runnable() {
public void run() {
try {
Socket socket = new Socket(targetIP, targetPort);
PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
while(isRunning) {
synchronized(msgs){
Iterator<String> it = msgs.iterator();
while(it.hasNext()){
out.println(username + ": " + it.next());
}
// Clear messages to send
msgs.clear();
}
}
out.close();
socket.close();
} catch (UnknownHostException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
};
new Thread(senderT).start();
}
public void stop(){
isRunning = false;
}
public void sendMessage(String msg){
synchronized(msgs){
msgs.add(msg);
}
}
}
As the 'showUsage()' says, use this program as follows:
java SimpleChat.java username listening_port target_ip target_port
Example:
java SimpleChat.java Supuhstar 1234 127.0.0.1 1234
[To talk to yourself]
I think you should clarify some details regarding what exactly you mean by a "basic instant messaging program" and what your objectives actually are regarding this project.
In a 2011 comment, you mentioned that there should be no "central hub", but in a more recent comment, you say that you would like something more in line with Skype or iMessage, where users do not have to know which peer is the server... It is technically possible (using protocols such as mdns, dlna or ssdp) for the program to transparently search the local network for potential existing server nodes and have it either connect to the server peer if there is one, or establish itself as a local server for other nodes to connect to it. That is for example how Apple iChat's Bonjour protocol used to work. This is however a rather complex solution to implement right, and is definitely not in line with what is done by current mass market messaging programs.
Also establishing direct peer-to-peer communication between users pose several practical issues (particularly because of firewalls and NAT, but there are also concerns of confidentiality and security). Most protocols therefore relay most messages through the central server, and negotiate a direct connection only for the purpose of file transfers and audio/video calls.
For all these reasons, unless you are looking merely for an example of local network communication between two hosts, you most certainly want two distinct programs: a server and a client.
Then, assuming my assumption is correct, there are two other questions that need to be clarified. First, do you have an actual reason to conceive the protocol by yourself, or would it be acceptable to rather implement an existing protocol (such as XMPP, IRC, SIMPLE... there are tons). Even though these protocols might looks highly complex at first, it is almost always possible to implement only a subset these protocol's features/messages. Designing a naive network protocol by yourself isn't that difficult, but there are tons of potential mistakes (mostly inefficiencies, incompleteness and other minor issues) that you will have to go through. Maybe that is indeed what you are specifically aiming for (that is, gaining experience at designing a network protocol from scratch), but unless it is so, you should seriously opt for implementing an existing protocol. Indeed, working with an existing protocol will not only avoid such design mistakes, but better yet, you will gain significant knowledge from how others (generally experienced protocol designers) actually resolved problems they met along the way. Using an existing protocol will also make it much easier and more interesting for you to develop that program, given that you will for example be able to test your client and server programs independently by connecting from/to an official client/server implementation. You will also be able to exploit exiting protocol-decoders in traffic sniffing tools in order to debug messages going through.
The second important question is how realistic you would like the server program to be, and most importantly in regard to persistance. Should the server maintain a persistant list of users and authenticate them? Should the server store a list of allowed contacts for each user? Should the server allow store messages aimed at a peer that is currently offline or that can't be reached at that exact moment? Real messaging server programs generally do such things, and though implementing such mechanisms isn't highly difficult, it is best considered early in the design of a program's architecture. For example, should you decide that these features are indeed desirable, then it might turn out to be much more interesting for you to immediately design your server around a persistant message queue engine, such as ActiveMQ...
I know this is not the examples you were asking for, but I still hope these thoughts may help you.
As said before, there is a lot of things that you need to put a real chat to work.
But i belive that you want something to start. And if you know the address and the port of the other "client" it is easy.
Extreme simple "chat" implementation
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.net.Socket;
import javax.net.ServerSocketFactory;
import javax.net.SocketFactory;
public class SimpleChat {
protected boolean running = true;
protected int port;
private Thread server;
public static void main(String... arg) {
//create 2 clients in the localhost to test
SimpleChat app1 = new SimpleChat(8989);
SimpleChat app2 = new SimpleChat(8988);
app1.sendMessage("localhost", 8988, "Message from app1 to app2");
app2.sendMessage("localhost", 8989, "Message from app2 to app1");
System.exit(0); // ugly way to kill the threads and exit
}
public SimpleChat(int port) {
this.port = port;
start();
}
public void start() {
server = new Thread(new Server());
server.start();
}
public boolean sendMessage(String host, int port, String message) {
try {
//Connect to a server on given host and port and "send" the message
InetSocketAddress destination
= new InetSocketAddress(host, port);
Socket s = SocketFactory.getDefault().createSocket();
s.connect(destination);
OutputStream out = s.getOutputStream();
out.write(message.getBytes());
out.flush();
out.close();
s.close();
return true;
} catch (Exception e) {
e.printStackTrace();
return false;
}
}
public void messageRecived(String message) {
System.out.println("Message recived: " + message);
}
public void stop() {
this.running = false; // only stop after a socked connection
}
class Server implements Runnable {
public void run() {
try {
//Create a server socket to recieve the connection
ServerSocket ss = ServerSocketFactory.getDefault()
.createServerSocket(port);
while (running) {
Socket s = ss.accept();
InputStream in = s.getInputStream();
StringBuilder message = new StringBuilder();
int len;
byte[] buf = new byte[2048];
while ((len = in.read(buf)) > -1) {
if (len > 0) {
message.append(new String(buf, 0, len));
}
}
messageRecived(message.toString());
}
} catch (Exception e) {
e.printStackTrace();
System.exit(-1);
}
}
}
}
I am using Restlet to implement a web service. The client (also uses Restlet) makes many consecutive calls to the server, but after a small number of calls complete successfully, further calls hang the server, which shows the message:
INFO: Stop accepting new connections and transactions. Consider increasing the maximum number of threads.
I tried:
getContext().getParameters().add("maxThreads", "200");
but that does not help. In any case, it seems like the client should be able to make an unlimited number of calls, and increasing maxThreads just ups the limit. It looks like I am not freeing up some resource or disconnecting after each client call, but I do not know how to do so.
The following (small as I could make it) stand alone program demonstrates the problem. It starts a simple server and then a client calls it a bunch of times:
/** You may copy, modify, and re-use this code as you see fit - Jim Irrer */
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import org.restlet.Application;
import org.restlet.Component;
import org.restlet.Request;
import org.restlet.Response;
import org.restlet.Restlet;
import org.restlet.Server;
import org.restlet.data.MediaType;
import org.restlet.data.Method;
import org.restlet.data.Protocol;
import org.restlet.data.Status;
import org.restlet.representation.InputRepresentation;
import org.restlet.representation.Representation;
import org.restlet.resource.ClientResource;
import org.restlet.resource.Directory;
public class SimpleServerPut extends Component implements Runnable {
private static final int PORT = 8080;
private static int readToByteArray(InputStream inputStream, byte[] buf) throws IOException {
int length = 0;
int b;
while ((b = inputStream.read()) != -1) {
buf[length++] = (byte)b;
}
return length;
}
#Override
public void run() {
getContext().getParameters().add("maxThreads", "200");
// Create the HTTP server and listen on port PORT
SimpleServerPut simpleServer = new SimpleServerPut();
Server server = new Server(Protocol.HTTP, PORT, simpleServer);
simpleServer.getClients().add(Protocol.FILE);
// Create an application
Application application = new Application(simpleServer.getContext()) {
#Override
public Restlet createRoot() {
return new Directory(getContext(), "C:");
}
};
// Attach the application to the component and start it
simpleServer.getDefaultHost().attach("/stuff/", application);
try {
server.start();
}
catch (Exception ex) {
ex.printStackTrace();
}
}
#Override
public void handle(Request request, Response response) {
// assume the worst
response.setStatus(Status.CLIENT_ERROR_METHOD_NOT_ALLOWED);
response.setEntity("No no - Bad client! Only do PUTs.", MediaType.TEXT_PLAIN);
try {
if (request.getMethod() == Method.PUT) {
InputStream inputStream = request.getEntity().getStream();
byte[] buf = new byte[64*1024];
int totalLength = readToByteArray(inputStream, buf);
response.setStatus(Status.SUCCESS_OK);
String msg = "Number of bytes received: " + totalLength;
response.setEntity(msg, MediaType.TEXT_PLAIN);
System.out.println("server: " + msg);
return;
}
}
catch (Exception ex) {
ex.printStackTrace();
}
}
private static String callServer() throws IOException {
String urlText = "http://localhost:" + PORT + "/";
ClientResource clientResource = new ClientResource(urlText);
clientResource.setReferrerRef(urlText);
byte[] buf = new byte[1000];
for (int i = 0; i < buf.length; i++) {
buf[i] = (byte)((int)'a' + (i%26));
}
ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(buf);
Representation representation = new InputRepresentation(byteArrayInputStream, MediaType.APPLICATION_OCTET_STREAM);
Representation representation2 = clientResource.put(representation);
byte[] responseBuf = new byte[16*1024];
int length = readToByteArray(representation2.getStream(), responseBuf);
Response response = clientResource.getResponse();
Status status = response.getStatus();
return "status: " + status + " message: " + new String(responseBuf, 0, length);
}
// Start server and call it a bunch of times
public static void main(String[] args) throws Exception {
SimpleServerPut simpleServer = new SimpleServerPut();
new Thread(simpleServer).start();
Thread.sleep(200); // cheap trick to make sure that server is running
// make a bunch of client calls
for (int t = 0; t < 100; t++) {
System.out.println("client count: " + (t+1) + " " + callServer());
}
System.exit(0);
}
}
We were only able to solve the problem by stopping the ClientResource's associated client directly (using Restlet version 2.0.15):
Client c = (Client)clientResource.getNext();
try {
c.stop();
} catch (Exception e) {
//handle exception
}
Add a line so that the client releases the resource:
Response response = clientResource.getResponse();
Status status = response.getStatus();
clientResource.release(); // add this line
to the client and everything works. Eventually the server times out if the client dies, but that takes a while.
I've solved my problem downloading the last stable release of the Restlet API
Apparently the .jar the I've been using were an old version where the release() command doesn't make any effect.
Before the update the client log only outputs the start of the client:
Sep 05, 2012 9:50:19 AM org.restlet.engine.http.connector.HttpClientHelper start
INFO: Starting the default HTTP client
Now it are outputing the stop too:
Sep 05, 2012 9:50:19 AM org.restlet.engine.http.connector.HttpClientHelper stop
INFO: Stopping the default HTTP client
In addition to calling ClientResource.release(), you may want to call exhaust() on the representation.
Representation responseRepresentation = response.getEntity();
if (responseRepresentation != null) {
try {
responseRepresentation.exhaust();
} catch (IOException e) {
// handle exception
}
responseRepresentation.release();
}
Related discussion in this thread.