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Client Server File transfer Chat Java GUI

i have a client and a server,
1) client should send choose files and send them to server
2) client should send a command message so that the server knows that the incoming is a file not a message (thats why i have "SF" which stands for send file)
3) server receives files and store them somewhere in the system
Also, i dont want to close the socket after i send/receive files (because this is done when the client clicks on disconnect button)
Below is my code but it does not work for some reason, if someone can help me fix it.
Client
public void sendFiles(String file) {
this.out.print("SF");
this.out.flush();
File myfile = new File(file);
// Get the size of the file
long length = myfile.length();
if (length > Integer.MAX_VALUE) {
System.out.println("File is too large.");
}
byte[] bytes = new byte[(int) length];
FileInputStream fis;
try {
fis = new FileInputStream(myfile);
BufferedInputStream bis = new BufferedInputStream(fis);
BufferedOutputStream out = new BufferedOutputStream(sock.getOutputStream());
int count;
while ((count = bis.read(bytes)) > 0) {
out.write(bytes, 0, count);
}
System.out.println("count "+bytes.length);
// this.out.flush();
out.flush();
// out.close();
fis.close();
bis.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
Server
public void recvFile() {
InputStream is = null;
FileOutputStream fos = null;
BufferedOutputStream bos = null;
int bufferSize = 0;
try {
is = sock.getInputStream();
bufferSize = sock.getReceiveBufferSize();
System.out.println("Buffer size: " + bufferSize);
fos = new FileOutputStream("/Users/day/Documents/Parallels/server.txt");
bos = new BufferedOutputStream(fos);
byte[] bytes = new byte[bufferSize];
int count;
while ((count = is.read(bytes)) > 0) {
bos.write(bytes, 0, count);
}
System.out.println("bytes "+bytes.length);
System.out.println("count "+count);
bos.flush();
bos.close();
// is.close();
// sock.close();
} catch (IOException e) {
System.out.println("ERROR" +e);
}
Also in the server side; this is how i jump to the method recvFile();
if (message.contains("SF")) {
recvFile();
}
MORE explanation about my problem:
It does not work in a sense that i dont know if the file is actually sent properly? or the file received properly because i get 0 bytes in the received file. Also, this is the thing i dont want to close the connection because this is a chat so how can i let the server know that this is the end of file?
Can someone help me making the code works because i dont know whats wrong? thanks

Could you kindly elaborate on the error that you are getting. That may help in answering. Because, prima facie the code structure looks fine.
Additionally, I presume that you are using TCP connection for file transfer.
P.S.: I couldn't add a comment to the question, so asking question here.

java socket programming to send and receive file between two machines

I am trying to communicate between two machines using socket programming.
What I basically need is both machines should be able to send and receive files. The code I am pasting below is not showing any error but the server side program seems to be running indefinitely, i.e., it is not terminating. It got stuck on the line marked with comment stuck here.
In this code, initially, server is sending the file named "file.txt" and client is receiving it and saving the file with name "copy.txt". Later client is sending a file named "file2.txt" and server is receiving and saving it with name "copy2.txt".
Can someone please tell me the error and suggest some improvements?
//server side code
import java.net.*;
import java.io.*;
public class server
{
public static void main (String [] args ) throws IOException
{
//sending file started
ServerSocket serverSocket = new ServerSocket(16167);
Socket socket = serverSocket.accept();
System.out.println("Accepted connection : " + socket);
File transferFile = new File ("/Users/abhishek/desktop/file.txt");
byte [] bytearray = new byte [(int)transferFile.length()];
FileInputStream fin = new FileInputStream(transferFile);
BufferedInputStream bin = new BufferedInputStream(fin);
bin.read(bytearray,0,bytearray.length);
OutputStream os = socket.getOutputStream();
System.out.println("Sending Files...");
os.write(bytearray,0,bytearray.length);
os.flush();
System.out.println("File transfer complete");
//socket.close();
//sending comleted
//receiving file started
int filesize=1022386;
int bytesRead=0;
int currentTot = 0;
byte [] bytearray1 = new byte [filesize];
InputStream is = socket.getInputStream();
FileOutputStream fos = new FileOutputStream("/Users/abhishek/desktop/copy2.txt");
//fos.flush();
BufferedOutputStream bos = new BufferedOutputStream(fos);
//bos.flush();
System.out.println("not moving ahead!!!");//program stucked here
bytesRead = is.read(bytearray1,0,bytearray1.length);
currentTot = bytesRead;
System.out.println("current"+currentTot);
do
{
bytesRead = is.read(bytearray1, currentTot, (bytearray1.length-currentTot));
if(bytesRead >= 0)
currentTot += bytesRead;
System.out.println("current"+currentTot);
} while(bytesRead > -1);
System.out.println("outside current"+currentTot);
bos.write(bytearray1, 0 , currentTot);
bos.flush();
//receiving complete
System.out.println("Receving file completed");
socket.close();
}
}
//client side code
import java.net.*;
import java.io.*;
public class client
{
public static void main (String [] args ) throws IOException
{
int filesize=1022386;
int bytesRead=0;
int currentTot = 0;
Socket socket = new Socket("localhost",16167);
byte [] bytearray = new byte [filesize];
InputStream is = socket.getInputStream();
FileOutputStream fos = new FileOutputStream("/Users/abhishek/desktop/copy.txt");
BufferedOutputStream bos = new BufferedOutputStream(fos);
bytesRead = is.read(bytearray,0,bytearray.length);
currentTot = bytesRead;
do
{
bytesRead = is.read(bytearray, currentTot, (bytearray.length-currentTot));
if(bytesRead >= 0)
currentTot += bytesRead;
} while(bytesRead > -1);
System.out.println("current"+currentTot);
bos.write(bytearray, 0 , currentTot);
bos.flush();
bos.close();
System.out.println("receiving first file completed!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
//sending file
System.out.println("sending second file started!");
File transferFile = new File ("/Users/abhishek/desktop/file2.txt");
byte [] bytearray2 = new byte [(int)transferFile.length()];
FileInputStream fin = new FileInputStream(transferFile);
BufferedInputStream bin = new BufferedInputStream(fin);
bin.read(bytearray2,0,bytearray2.length);
OutputStream os = socket.getOutputStream();
os.flush();
os.write(bytearray2,0,bytearray2.length);
os.flush();
System.out.println("sending second file completed!");
//sending complete
socket.close();
}
}

Does the System.out.println("not moving ahead!!!");//program stucked here line actually execute? if so, then the problem is that the InputStream.read() functions are blobking functions; they will stop execution of the program ("block") until they are able to complete.
From the JavaDoc for InputStream:
Reads up to len bytes of data from the input stream into an array of bytes. An attempt is made to read as many as len bytes, but a smaller number may be read. The number of bytes actually read is returned as an integer.
This method blocks until input data is available, end of file is detected, or an exception is thrown.
Since you aren't getting an exception, this means that when you call .read(), there is no data available to be read, and you program sits around waiting for data to read (that never arrives). You should check that your client program is actually sending the data in the first place.

I'd bet
bytesRead = is.read(bytearray1,0,bytearray1.length);
is where you're really getting stuck. The problem normally if you are stuck here is that the other side of the communication has not sent any data, there's nothing to read, and your thread is stuck waiting for it to send.
on your client side, you call
bos.close();
after sending the first message. This is going to cause the socket to close as well, which will throw an IOException on your server end, and because you are not catching the IOException, your server program will just exit.
How much socket experience do you have? If you are just beginning with sockets, you might want to check out the extensions I wrote around this, starting with ServerSocketEx and DataFetcher.

client/server to send a file get stuck somewhere

I have implemented a client/server to send files . When there is no more messages exchanged after sending the file , the code works perfectly , but if the client sends some string to the server directly after the code of receiving the file both client and server stop doing anything and the file is not sent it's something like if they both get stuck in deadlock but I'm not really sure :
Here is the code to send the file without sending anything after it , which works:
Client
String filename;
BufferedReader UIn = new BufferedReader(new InputStreamReader(System.in));
Socket peer = new Socket("localhost",9999);
System.out.print("Enter the file name to download :");
filename= UIn.readLine();
///////////////////////////////
DataOutputStream OutToServer;
OutToServer = new DataOutputStream(peer.getOutputStream());
OutToServer.writeBytes(filename+"\n");
FileOutputStream fos = new FileOutputStream(new File("D:/new.txt"));
BufferedOutputStream out = new BufferedOutputStream(fos);
InputStream in = peer.getInputStream();
buffer = new byte[1024];
while((count=in.read(buffer))>0)
{
fos.write(buffer, 0, count);
System.out.println(buffer);
}
fos.close();
System.out.println("done");
Server:
ServerSocket server =null;
try {
server = new ServerSocket(9999);
while(true)
{
client= server.accept();
//System.out.println("Connection accepted");
BufferedReader inFromClient = new BufferedReader(new InputStreamReader(client.getInputStream()));
DataOutputStream outToclient =new DataOutputStream(client.getOutputStream());
String request=inFromClient.readLine();
file = new File(request);
if (file.exists())
{
OutputStream out = client.getOutputStream();
BufferedInputStream in = new BufferedInputStream(new FileInputStream(file));
while((count =in.read(buffer)) >0)
{
out.write(buffer,0,count);
out.flush();
}
}
// System.out.println(request);
// outToclient.writeBytes("alaa\n");
}
} catch (IOException ex) {
Logger.getLogger(ServerWork.class.getName()).log(Level.SEVERE, null, ex);
}
But if I try to send anything after the loop between client and server it stops working . Is it because I'm using readLine() and writeBytes()?

You are using both DataOutputStream and OutputStream. I think that they
should work together but what I guess you should do is to flush the buffer (or close it).
After you're done writing everything you want to send, some data may still be in the buffer. Now you will have to flush the buffer, to force it to send all the data.(as it is said here).
outToclient.writeBytes("alaa\n");
outToclient.flush();

Proper way of closing Streams in Java Sockets

I saw some posts about this but I still can't find an answer.
This is how my server interacts with the client:
public void run () {
try {
//Read client request
InputStream is = server.getInputStream();
byte[] buff = new byte[1024];
int i;
ByteArrayOutputStream bos = new ByteArrayOutputStream();
while ((i = is.read(buff, 0, buff.length)) != -1) {
bos.write(buff, 0, i);
System.out.println(i + " bytes readed ("+bos.size()+")");
}
is.close();
is = null;
//Do something with client request
//write response
OutputStream os = server.getOutputStream();
os.write("server response".getBytes());
os.flush();
os.close();
os = null;
} catch (IOException ioe) {
ioe.printStackTrace();
}
}
And this is the client side:
public void run() {
try {
InetAddress serverAddr = null;
serverAddr = InetAddress.getByName("10.0.2.2");
socket = new Socket(serverAddr, 5000);
//Send Request to the server
OutputStream os = socket.getOutputStream();
os.write(jsonRequest.toString().getBytes("UTF-8"));
os.flush();
os.close();
os = null;
//Read Server Response
InputStream is = socket.getInputStream();
byte[] buff = new byte[1024];
int i;
ByteArrayOutputStream bos = new ByteArrayOutputStream();
while ((i = is.read(buff, 0, buff.length)) != -1) {
bos.write(buff, 0, i);
System.out.println(i + " bytes readed ("+bos.size()+")");
}
is.close();
is = null;
//Do something with server response
} catch (UnknownHostException uhe) {
sendCallbackError(uhe);
} catch (IOException ioe) {
sendCallbackError(ioe);
}
}
As you can see, the client connects and send a request. Server read that request then writes a response that the client will read.
The problem with this code is the OutputStream.close() in the client and InputStream.close() in the server. As stated in the Javadocs, closing the stream will close the Socket. The result is that when the client tries to read the server response, the Socket is already closed.
I've managed to overcome this by calling Socket.shutdownInput and Socket.shutdownOutput instead. However I am still thinking whether this is the proper way of doing it
As a note, closing the streams with close() when server writes the response or when the client reads it doesn't create problems (I would guess the closing is synchronized between client and server).
So my questions are:
Is using the Socket shutdown methods a proper way?
Can I keep closing the last streams with close() (when sending and reading
response from server)
Could it happen that closing with shutdown would keep some data in
the buffer and wouldn't be sent?

You can do the following:
try{
}catch(){
}finally{
if(is!=null){
is.close();
}
if(os!=null){
os.close();
}
}

The problem with this code is the OutputStream.close() in the client and InputStream.close() in the server. As stated in the Javadocs, closing the stream will close the Socket.
Correct but the InputStream in the server isn't connected directly to a Socket: it is connected to something you don't know anything about. You can close it with impunity, although again you don't need to close it at all. You can close the OutputStream in the server if you like: although, again, as it isn't connected directly to a Socket, it may or may not have any effect other than flushing.
To address your actual question, you don't need to close the output stream in the client, but you do need to send an appropriate Content-Length: header. That way the server knows how much to read from the client. If this is only a GET request the content-length may well be zero. You don't need to call shutdownOutput(), although I guess there is nothing to stop you, and calling shutdownInput() doesn't do anything to the network anyway so again there is no point to it.

Java File Transfer getting stuck halfway

I am trying to send a file (an image sent as a byte array) with the client and then the server should receive said byte array to make further use of it. However when I click on the "send" to send the image the file transfer starts (as I get a sentImage.jpg in my Desktop) but it gets stuck for some reason I can't figure out and the image never gets correctly sent.
Here's the part that receives from the server (it already accepted the connection):
public void run(){
try {
byte[] receivedData = new byte[1024];
BufferedInputStream bis = new BufferedInputStream(client.getInputStream());
// while(bis.read() != -1){
s.acquireUninterruptibly();
BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("C:\\Users\\Admin\\Desktop\\sentImage.jpg"));
while ((incoming = bis.read(receivedData)) != -1) {
bos.write(receivedData, 0, incoming);
}
s.release();
n.release();
bis.close();
bos.flush();
// }
} catch (IOException e) {
e.printStackTrace();
}
}
and the client is sending here:
public void sendImageResult() {
new Thread(new Runnable() {
public void run() {
try {
int inside = 0;
Socket socket = new Socket("localhost", 4444);
File myImageFile = new File("C:\\Users\\Admin\\Desktop\\test.jpg");
BufferedInputStream bis = new BufferedInputStream(new FileInputStream(myImageFile));
BufferedOutputStream bos = new BufferedOutputStream(socket.getOutputStream( ));
byte[] byteArray = new byte[1024];
while ((inside = bis.read(byteArray)) != -1){
bos.write(byteArray,0,inside);
}
bis.close();
bos.flush();
} catch (UnknownHostException ex) {
System.out.println("No se pudo establecer la conexión.");
ex.printStackTrace();
} catch (FileNotFoundException fnf){
fnf.printStackTrace();
} catch(IOException ioe){
ioe.printStackTrace();
}
}
}).start();
}

It does not appear that the OutputStream (bos) that is used to write to disk is being closed. This could lead to unexpected results.

As jt said, the OutputStream writing to disk is not being closed, but neither is the OutputStream being used to send the data, nor is the Socket being closed from the sending side. The sending side may be buffering the data at the tcp level, waiting for more bytes before sending the last packet. You are calling flush, but that can be ignored, it's not guaranteed to work like you expect. Another thing to try is calling shutdownOutput on the Socket and seeing if that forces it to flush. You can also try setTcpNoDelay(true) when you open the Socket. If none of that works, get a tcp trace program (I like tcpdump) and use it to see if the packets are actually being sent, it will at least narrow it down to either the send or receive end of things.