I have tomcat installed on vps, everything has been configured, but how do I host my java server on it? What extension should I use and which folder should I put? Or do I need to change something in the Server.java?
Here he is:
public class Server {
public static void main(String[] ar) throws IOException {
int port = 8080;
try {
ServerSocket ss = new ServerSocket(port);
System.out.println("Waiting for a client...");
Socket socket = ss.accept();
System.out.println("Got a client!");
System.out.println();
InputStream sin = socket.getInputStream();
OutputStream sout = socket.getOutputStream();
DataInputStream in = new DataInputStream(sin);
DataOutputStream out = new DataOutputStream(sout);
String line = null;
while(true) {
line = in.readUTF();
System.out.println("The dumb client just sent me this line : " + line);
System.out.println("I'm sending it back...");
out.writeUTF(line);
out.flush();
System.out.println("Waiting for the next line...");
System.out.println();
}
} catch(Exception x) { x.printStackTrace(); }
}
}
Related
I'm an amateur in java socket programming. As I say in title, When I using PrintStream for socket output,it works;but it doesn't work if I using simply OutputStream.
I know the the client connected to the server cause' the server got the info of the client.So I think there must be something wrong with I/O stream, not the socket connection.
btw, I even use the flush() method for OutputStream.I think flush() will force to send all bytes, but it seems like it didn't work.
The Client Code:#line 12:
public class Clinet {
public static void main(String[] args) throws UnknownHostException, IOException {
System.out.println("==========Client============");
Socket socket = new Socket("localhost", 8888);// Server's addr and port
socket.setSoTimeout(3000);
InputStream inputStream = socket.getInputStream();
OutputStream outputStream = socket.getOutputStream();
String msgToSent = "Hello TCP";
outputStream.write(msgToSent.getBytes());
outputStream.flush();// FIXME:why flush() didn't work?why msg wasn't sent.
// read from socket input
String receivedMsg = new String(inputStream.readAllBytes());
System.out.println(receivedMsg);
socket.close();
}
}
When I using a filter stream like PrintStream,the msg can be sent to server.
The Server Code: if using PrintStream it will work perfectly with the Client:
public class Server {
public static void main(String[] args) throws IOException {
ServerSocket serverSocket = new ServerSocket(8888);
while (true) {
Socket client = serverSocket.accept();
new Thread(new ServerHandler(client)).start();
}
}
}
class ServerHandler implements Runnable {
private Socket client;
ServerHandler(Socket client) {
this.client = client;
}
#Override
public void run() {
try {
InetAddress clientAddr = client.getInetAddress();
int clientPort = client.getPort();
System.out.println("client connected # " + clientAddr + ":" + clientPort);
InputStream inputStream = client.getInputStream();
OutputStream outputStream = client.getOutputStream();
while (true) {
String msg = new String(inputStream.readAllBytes());// FIXME: Why Server didn't receive Client's msg?
System.out.print("/" + clientAddr + "#" + clientPort + " : ");
System.out.println(msg);
String reply = "I received " + msg.length() + " words.";// return how many words the server got.
outputStream.write(reply.getBytes());
outputStream.flush();// flush to ensure send all msg,but seems doesn't work
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
I'm trying to make a connection between a client and server in java but when I run the server it gives a "Connection refused: connect" I don't know what to do and I'm really new to java networking can you please help me? here's my server code:
class reserver {
static int serverPort = 6667;
static int serverPort1 = 6668;
static String Message,input;
String ip = "127.0.0.1";
public reserver(){
try{
InetAddress ipAddress = InetAddress.getByName(ip);
Socket socket = new Socket(ipAddress,serverPort);
OutputStream sout = socket.getOutputStream();
InputStream sin = socket.getInputStream();
DataOutputStream out = new DataOutputStream(sout);
out.writeUTF(input);
out.flush();
}catch(IOException e){
System.out.print(e.getMessage());
}
}
public static void main(String [] args){
new reserver();
try{
ServerSocket ss = new ServerSocket(serverPort1);
int i = 0;
while(true){
i++;
Socket socket = ss.accept();
OutputStream sout = socket.getOutputStream();
InputStream sin = socket.getInputStream();
DataInputStream in = new DataInputStream(sin);
DataOutputStream out = new DataOutputStream(sout);
input = in.readUTF();
System.out.println("Message [" + i + "]" +input);
}
}catch(IOException e){
System.out.print(e.getMessage());
}
}
}
And here's my clients code:
class reclient {
String ip = "127.0.0.1";
static int serverPort = 6667;
static int serverPort1 = 6668;
static String Message,input;
public reclient(){
try{
Scanner s = new Scanner(System.in);
System.out.print("Enter Text: ");
input = s.nextLine();
InetAddress ipAddress = InetAddress.getByName(ip);
Socket socket = new Socket(ipAddress,serverPort);
OutputStream sout = socket.getOutputStream();
InputStream sin = socket.getInputStream();
DataInputStream in = new DataInputStream(sin);
DataOutputStream out = new DataOutputStream(sout);
out.writeUTF(input);
out.flush();
}catch(IOException e){
System.out.print(e.getMessage());
}
}
public static void main(String [] args){
new reclient();
try{
ServerSocket ss = new ServerSocket(serverPort1);
int i = 0;
while(true){
i++;
Socket socket = ss.accept();
OutputStream sout = socket.getOutputStream();
InputStream sin = socket.getInputStream();
DataInputStream in = new DataInputStream(sin);
DataOutputStream out = new DataOutputStream(sout);
input = in.readUTF();
System.out.println("Message [" + i + "]" +input);
}
}catch(IOException e){
System.out.print(e.getMessage());
}
}
}
It looks like your code is swapped for server and client.
Look at :
how do i connect to the server socket using the ip address and port number( client is running on a different machine than server)
Client program
public class client implements Runnable {
protected static String server_IP = "141.117.57.42";
private static final int server_Port = 5555 ;
protected static String client_IP ;
public static void main(String[] args) throws IOException{
final String host = "localhost";
int init = 0 ;
try {
InetAddress iAddress = InetAddress.getLocalHost();
client_IP = iAddress.getHostAddress();
System.out.println("Current IP address : " +client_IP);
} catch (UnknownHostException e) {
}
try {System.out.println("hello1");
Socket socket = new Socket(server_IP,server_Port);
System.out.println("hello3");
init = initialize(socket);
}catch (SocketException e) {
System.out.println("Error: Unable to connect to server port ");
}
if (init == 0 ){
System.out.println("error: Failed to initialize ");
System.exit(0);
}
//Thread init_Thread = new Thread();
}
private static int initialize(Socket socket ) throws IOException{
System.out.println("hello");
int rt_value = 0 ;
OutputStream os = socket.getOutputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
PrintWriter pw = new PrintWriter(os, true);
System.out.println("server: " + br.readLine());
pw.println("192.343.34.321");
// BufferedReader userInputBR = new BufferedReader(new InputStreamReader(System.in));
//String userInput = userInputBR.readLine();
//out.println(userInput);
socket.close();
return rt_value = 1 ;
}
public void run(){
}
}
server side program
public class server {
protected static String server_IP ;
public static void main(String[] args) throws IOException {
int server_Port = 5555 ;
try {
InetAddress iAddress = InetAddress.getLocalHost();
server_IP = iAddress.getHostAddress();
System.out.println("Server IP address : " +server_IP);
} catch (UnknownHostException e) {
}
ServerSocket serverSocket = new ServerSocket(server_Port);
while (true) {
Socket socket = serverSocket.accept();
OutputStream os = socket.getOutputStream();
PrintWriter pw = new PrintWriter(os, true);
InputStreamReader isr = new InputStreamReader(socket.getInputStream());
pw.println("Connection confirmed ");
BufferedReader br = new BufferedReader(isr);
String str = br.readLine();
pw.println("your ip address is " + str);
pw.close();
//socket.close();
//System.out.println("Just said hello to:" + str);
}
How do I connect to the server socket using the ip address and port number (client is running on a different machine than server).
When I change the server_IP in client to "local host", it works perfectly.
To connect in your code you use:
Socket socket = new Socket(server_IP,server_Port);
So you could use:
Socket socket = new Socket("192.168.1.4", 5555);
It looks like you have this in your code so I'm not sure what problem you're having.
Don't forget that you have to setup your router to forward ports if it is located outside of your local network.
http://www.wikihow.com/Set-Up-Port-Forwarding-on-a-Router
Don't forget that if you are running a firewall, this can also interfere with the connection.
Update /etc/hosts
Add following line
127.0.1.1 192.168.10.109
This is a simple client-server program. It works fine when executed in a single computer. But, it doesn't work when executed in two different laptops connected using WiFi.
Here's the code:
Server:
public class Server
{
private static int port;
private ServerSocket serverSocket;
public void GreetingServer(int port) throws IOException
{
serverSocket = new ServerSocket(port);
serverSocket.setSoTimeout(20000);
while(true)
{
try
{
System.out.println("Waiting for client");
Socket server = serverSocket.accept();
System.out.println("Connected");
DataInputStream in =new DataInputStream(server.getInputStream());
System.out.println(in.readUTF());
DataOutputStream out = new DataOutputStream(server.getOutputStream());
out.writeUTF("Thank you for connecting to ");
server.close();
}
catch(SocketTimeoutException s)
{
System.out.println("Socket timed out!");
break;
}
catch(IOException e)
{
e.printStackTrace();
break;
}
}
}
public static void main(String [] args)
{
port=9001;
try
{
Server s=new Server();
s.GreetingServer(port);
}
catch(IOException e)
{
e.printStackTrace();
}
}
}
Client:
public class Client
{
private static String serverName;
public static void main(String [] args)
{
String sName = "192.168.xxxx.x";
int port = 9001;
try
{
System.out.println("Connecting to " + sName
+ " on port " + port);
Socket client = new Socket(sName, port);
System.out.println("Connected");
OutputStream outToServer = client.getOutputStream();
DataOutputStream out = new DataOutputStream(outToServer);
out.writeUTF("Hello from " + client.getLocalSocketAddress());
InputStream inFromServer = client.getInputStream();
DataInputStream in = new DataInputStream(inFromServer);
System.out.println("Server says " + in.readUTF());
client.close();
}catch(IOException e)
{
}
}
}
What could be the problem? Please me..
Thanks in advance..
There are lot of close_wait connection, when ever a client client sends the message to the server and comes out the TCP FSM stuck in the CLOSE_WAIT STATE
This the Client code,
public class Client1
{
private static Socket socket;
public static void main(String args[])
{
try
{
String host = "localhost";
int port = 25000;
InetAddress address = InetAddress.getByName(host);
socket = new Socket(address, port);
//Send the message to the server
OutputStream os = socket.getOutputStream();
OutputStreamWriter osw = new OutputStreamWriter(os);
BufferedWriter bw = new BufferedWriter(osw);
String number = "2";
String sendMessage = number + "\n";
bw.write(sendMessage);
bw.flush();
System.out.println("Message sent to the server : "+sendMessage);
//Get the return message from the server
InputStream is = socket.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String message = br.readLine();
System.out.println("Message received from the server : " +message);
}
catch (Exception exception)
{
exception.printStackTrace();
}
finally
{
//Closing the socket
try
{
socket.close();
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
}
This the Server code which listen to the upcoming connection
public class Server1
{
private static Socket socket;
public static void main(String[] args)
{
try
{
int port = 25000;
ServerSocket serverSocket = new ServerSocket(port);
System.out.println("Server Started and listening to the port 25000");
//Server is running always. This is done using this while(true) loop
while(true)
{
//Reading the message from the client
socket = serverSocket.accept();
InputStream is = socket.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String number = br.readLine();
System.out.println("Message received from client is "+number);
//Multiplying the number by 2 and forming the return message
String returnMessage;
try
{
int numberInIntFormat = Integer.parseInt(number);
int returnValue = numberInIntFormat*2;
returnMessage = String.valueOf(returnValue) + "\n";
}
catch(NumberFormatException e)
{
//Input was not a number. Sending proper message back to client.
returnMessage = "Please send a proper number\n";
}
//Sending the response back to the client.
OutputStream os = socket.getOutputStream();
OutputStreamWriter osw = new OutputStreamWriter(os);
BufferedWriter bw = new BufferedWriter(osw);
bw.write(returnMessage);
System.out.println("Message sent to the client is "+returnMessage);
bw.flush();
}
}
catch (Exception e)
{
e.printStackTrace();
}
finally
{
try
{
socket.close();
}
catch(Exception e){}
}
}
}
The output TCP FSM
-bash:~$ netstat -an | grep 25000
tcp4 0 0 127.0.0.1.25000 127.0.0.1.56459 CLOSE_WAIT
tcp46 0 0 *.25000 *.* LISTEN
You're closing the accepted socket in the wrong place. It needs to be inside the accept loop.