i've write a code for transferring file over sockets,
the file is transfers properly but it isn't closed even after calling .close() method.
however the file closes after closing the "sockets", but i want to keep the connection open.
here the server sends the file to client
SERVER CODE
public void sendFile(String sfileName) throws IOException{
try{
in = new FileInputStream(sfileName);
out = socket.getOutputStream();
transferData(in,out);
}
finally {
in.close();
in = null;
System.gc();
}
}
private void transferData(InputStream in, OutputStream out) throws IOException {
byte[] buf = new byte[8192];
int len = 0;
while(in.available()==0);
while ((len = in.read(buf)) != -1) {
out.write(buf, 0, len);
}
out.flush();
}
CLIENT CODE :
public void recieveFile(String rfileName) throws IOException{
try{
in = socket.getInputStream();
System.out.println("Reciever file : " + rfileName);
out = new FileOutputStream(rfileName);
transferData(in,out);
}
finally{
out.flush();
out.close();
out = null;
System.gc();
}
}
private void transferData(InputStream in, OutputStream out) throws IOException {
byte[] buf = new byte[8192];
int len = 0;
while(in.available()==0);
while ((len = in.read(buf)) != -1) {
out.write(buf, 0, len);
}
out.flush();
}
what is wrong with the code ?
I think you should use Socket.shutdownOutput()
Related
I'm trying to send a string which is the filename and then the file itself to a server. The string is being received and used to create the file by the server. However, there isn't any data actually written into the file by the server.
I got the file transfer to work before I added the Writer's (with the file names being hard-coded) to the server and client but now I can't get both to work at the same time.
Client:
public class Client {
public static void main(String[] args) throws Exception {
Scanner sc = new Scanner(System.in);
while (true) {
String fileName = sc.nextLine();
System.out.println(fileName);
try {
File file = new File(fileName);
Socket socket = new Socket("localhost", 15000);
OutputStream os = socket.getOutputStream();
Writer w = new OutputStreamWriter(os, "UTF-8");
w.write(fileName);
w.close();
os.flush();
byte[] mybytearray = new byte[(int) file.length()];
BufferedInputStream bis = new BufferedInputStream(new FileInputStream(file));
bis.read(mybytearray, 0, mybytearray.length);
os.write(mybytearray, 0, mybytearray.length);
os.flush();
os.close();
socket.close();
} catch (Exception e) { }
}
}
}
Server:
public class Server extends Thread {
public static final int PORT = 15000;
#Override
public void run() {
try {
ServerSocket serverSocket = new ServerSocket(PORT);
while (true) {
Socket sock = serverSocket.accept();
readFile(sock);
}
} catch (Exception e) {
}
}
private void readFile(Socket socket) throws Exception {
InputStream ois = socket.getInputStream();
Reader r = new InputStreamReader(ois, "UTF-8");
String filename = "";
int ch = r.read();
while(ch != -1) {
filename += (char) ch;
System.out.println(filename);
ch = r.read();
}
r.close();
System.out.println(filename);
FileOutputStream fos = new FileOutputStream(filename);
byte[] bytearr = new byte[4096];
System.out.println("Reading file...");
BufferedOutputStream bos = new BufferedOutputStream(fos);
while ((ois.read(bytearr)) > 0) {
bos.write(bytearr);
}
bos.close();
System.out.println("Writing file complete...");
}
public static void main(String[] args) {
new Server().start();
}
}
This is my solution, this approach needs some improvements:
Explanation:
In position 0: Length of file name
In position 1 to the length of the file name: filename as bytes.
In position 1 + length of file name til length: The content of the file.
Basically, I'm sending all the information to the server at once (This is one improvement that you will need to figure out).
Another improvement is to send the file by chunks and not all the file at once.
Client class:
public class Client {
public static void main(String[] args) throws Exception {
Scanner sc = new Scanner(System.in);
while (true) {
String fileName = sc.nextLine();
System.out.println(fileName);
try {
File file = new File(fileName);
byte[] mybytearray = new byte[1 + fileName.getBytes().length + (int) file.length()];
mybytearray[0] = (byte) fileName.length();
System.arraycopy(fileName.getBytes(), 0, mybytearray, 1, fileName.getBytes().length);
BufferedInputStream bis = new BufferedInputStream(new FileInputStream(file));
bis.read(mybytearray, fileName.getBytes().length + 1, (int) file.length());
Socket socket = new Socket("localhost", 15000);
OutputStream os = socket.getOutputStream();
os.write(mybytearray, 0, mybytearray.length);
os.flush();
os.close();
socket.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
Server class:
public class Server extends Thread {
public static final int PORT = 15000;
public static void main(String[] args) {
new Server().start();
}
#Override
public void run() {
try {
ServerSocket serverSocket = new ServerSocket(PORT);
while (true) {
Socket sock = serverSocket.accept();
readFile(sock);
}
} catch (Exception e) {
}
}
private void readFile(Socket socket) throws Exception {
InputStream ois = socket.getInputStream();
byte[] resultBuff = new byte[0];
byte[] buff = new byte[1024];
int k;
while ((k = ois.read(buff, 0, buff.length)) > -1) {
byte[] tbuff = new byte[resultBuff.length + k];
System.arraycopy(resultBuff, 0, tbuff, 0, resultBuff.length);
System.arraycopy(buff, 0, tbuff, resultBuff.length, k);
resultBuff = tbuff;
}
byte lengthOfFileName = resultBuff[0];
byte fileNameBytes[] = new byte[lengthOfFileName];
System.arraycopy(resultBuff, 1, fileNameBytes, 0, lengthOfFileName);
String filename = new String(fileNameBytes);
FileOutputStream fos = new FileOutputStream(filename + System.currentTimeMillis());
byte[] bytearr = new byte[resultBuff.length - (lengthOfFileName + 1)];
System.out.println("Writing file...");
System.arraycopy(resultBuff, lengthOfFileName + 1, bytearr, 0, bytearr.length);
BufferedOutputStream bos = new BufferedOutputStream(fos);
bos.write(bytearr);
bos.close();
System.out.println("Writing file complete...");
}
}
Hope this helps!
Happy coding time!
You need to close the File Ouptut Stream as well. With
bos.close;
Add
fos.close;
i am sending files from two java applications here the source code of the server and the client
public class FileClient {
private Socket s;
public FileClient(String host, int port, String file) {
try {
s = new Socket(host, port);
sendFile(file);
} catch (Exception e) {
e.printStackTrace();
}
}
public void sendFile(String file) throws IOException {
DataOutputStream dos = new DataOutputStream(s.getOutputStream());
FileInputStream fis = new FileInputStream(file);
byte[] buffer = new byte[4096];
while ((fis.read(buffer) > 0)) {
dos.write(buffer);
}
fis.close();
dos.close();
}
public static void main(String[] args) {
FileClient fc = new FileClient("192.168.0.167", 1988, "C:/Users/mhattabi/Desktop/fileData.txt");
}
}
and here the source code of the server
public class FileServer extends Thread {
private ServerSocket ss;
public FileServer(int port) {
try {
ss = new ServerSocket(port);
} catch (IOException e) {
e.printStackTrace();
}
}
public void run() {
while (true) {
try {
Socket clientSock = ss.accept();
saveFile(clientSock);
// ss.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
private void saveFile(Socket clientSock) throws IOException {
DataInputStream dis = new DataInputStream(clientSock.getInputStream());
FileOutputStream fos = new FileOutputStream("fileData.txt");
byte[] buffer = new byte[4096];
int filesize = 15123; // Send file size in separate msg
int read = 0;
int totalRead = 0;
int remaining = filesize;
while((read = dis.read(buffer)) > 0) {
totalRead += read;
System.out.println("read " + totalRead + " bytes.");
fos.write(buffer, 0, read);
}
fos.close();
dis.close();
}
public static void main(String[] args) {
FileServer fs = new FileServer(1988);
fs.start();
}
}
the problem that in the server i received the file but there is extra character in it look like this.Any help will be appreciated thanks
Usual problem.
while ((fis.read(buffer) > 0)) {
dos.write(buffer);
}
You're ignoring the count returned by the read, and assuming that it filled the buffer. It should be:
while ((count = fis.read(buffer) > 0)) {
dos.write(buffer, 0, count);
}
Curiously enough you have this right in the server. NB You don't need a DataOutputStream here.
byte[] buffer = new byte[4096];
I think the" extra character" come from this place;every time you write 4096 byte
,at last time it happened less than 4096 byte.and then you get extra character
I'm making simple Client-Server FileTransfer application in java.
Here is the concept of this application:
Client connects to server
Server shows menu to Client which looks like this
2a) Make copy of file on server
2b) Download copy of file from
server
2c) Exit
Client choose one of those options (Client sends message by ObjectOutputStream, code below).
The problem is when i choose one of options (for example Option #2a) I can't choose another one when previous is done. It says that socket is close.
There is my code:
Client:
public class Client {
private Socket s = new Socket("localhost",3002);
ObjectOutputStream oos = new ObjectOutputStream(s.getOutputStream());
ObjectInputStream ois = new ObjectInputStream(s.getInputStream());
FileInputStream fis;
public Client(String host, int port) throws IOException {
//s = new Socket(host, port);
try {
System.out.println("Hello!");
boolean finished = false;
Scanner sc = new Scanner(System.in);
while(!finished){
System.out.println("\n\n1.Make copy of file on server");
System.out.println("2.Restore copy");
System.out.println("3.Exit\n");
char c = sc.nextLine().charAt(0);
switch(c){
case '1':
this.sendMessage(1);
makeCopy();
oos.close();
break;
case '2':
this.sendMessage(2);
saveFile(s);
break;
case '3':
this.sendMessage(3);
finished=true;
System.exit(0);
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) throws IOException {
Client client = new Client("localhost",3002);
}
public void sendMessage(int message_id) throws IOException{
oos.writeInt(message_id);
oos.flush();
}
private void makeCopy() throws IOException {
File file = new File("D:\\klient\\doKopii.bmp");
File dest = new File("D:\\serwer\\kopiaPliku.bmp");
boolean ifExists = dest.exists();
if(ifExists && !file.isDirectory()){
System.out.println("Copy is already on server.");
}
else{
fis = new FileInputStream(file);
byte[] buffer = new byte[4096];
while (fis.read(buffer) > 0) {
oos.write(buffer);
}
}
//fis.close();
//oos.close();
}
private void saveFile(Socket clientSock) throws IOException {
//DataInputStream dis = new DataInputStream(clientSock.getInputStream());
FileOutputStream fos = new FileOutputStream("D:\\klient\\przywroconaKopia.bmp");
File zSerwera = new File("D:\\serwer\\kopiaPliku.bmp");
byte[] buffer = new byte[4096];
int filesize = (int)zSerwera.length();
int read = 0;
int totalRead = 0;
int remaining = filesize;
while((read = ois.read(buffer, 0, Math.min(buffer.length, remaining))) > 0) {
totalRead += read;
remaining -= read;
System.out.println("read " + totalRead + " bytes.");
fos.write(buffer, 0, read);
}
//fos.close();
//ois.close();
}
}
And Server side code:
public class Server extends Thread{
private ServerSocket ss;
Socket clientSock;
ObjectInputStream ois;
ObjectOutputStream oos;
//DataOutputStream dos;
FileInputStream fis;
//DataInputStream dis;
FileOutputStream fos;
public Server(int port) {
try {
ss = new ServerSocket(port);
} catch (IOException e) {
e.printStackTrace();
}
}
public void run() {
try {
while (true) {
clientSock = ss.accept();
oos = new ObjectOutputStream(clientSock.getOutputStream());
ois = new ObjectInputStream(clientSock.getInputStream());
serviceClient(clientSock);
}
}catch(Exception e){
e.printStackTrace();
}
}
public void serviceClient(Socket s) throws Exception{
int message_id;
try{
message_id = ois.readInt();
switch(message_id){
case 1:
saveFile(s);
oos.flush();
break;
case 2:
sendFile(s);
oos.flush();
break;
}
}catch(Exception e){
e.printStackTrace();
}
}
public void sendFile(Socket s) throws IOException {
File file = new File("D:\\serwer\\kopiaPliku.bmp");
fis = new FileInputStream(file);
byte[] buffer = new byte[4096];
while (fis.read(buffer) > 0) {
oos.write(buffer);
}
}
public void saveFile(Socket s) throws IOException{
//dis = new DataInputStream(s.getInputStream());
File copy = new File("D:\\serwer\\kopiaPliku.bmp");
if(copy.exists() && !copy.isDirectory()){
}
else{
fos = new FileOutputStream(copy);
File zSerwera = new File("D:\\klient\\doKopii.bmp");
byte[] buffer = new byte[4096];
int filesize = (int)zSerwera.length();
int read = 0;
int totalRead = 0;
int remaining = filesize;
while((read = ois.read(buffer, 0, Math.min(buffer.length, remaining))) > 0) {
totalRead += read;
remaining -= read;
System.out.println("read " + totalRead + " bytes.");
fos.write(buffer, 0, read);
}
}
}
public static void main(String[] args) {
Server server = new Server(3002);
server.start();
}
}
Exact Exception:
java.net.SocketException: Socket closed
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:116)
at java.net.SocketOutputStream.write(SocketOutputStream.java:153)
at java.io.ObjectOutputStream$BlockDataOutputStream.writeBlockHeader(ObjectOutputStream.java:1890)
at java.io.ObjectOutputStream$BlockDataOutputStream.drain(ObjectOutputStream.java:1875)
at java.io.ObjectOutputStream$BlockDataOutputStream.flush(ObjectOutputStream.java:1822)
at java.io.ObjectOutputStream.flush(ObjectOutputStream.java:719)
at com.luki.classes.Client.sendMessage(Client.java:58)
at com.luki.classes.Client.<init>(Client.java:33)
at com.luki.classes.Client.main(Client.java:53)
Where do I have to close all of those streams to prevent socket closing ?
You close your ObjectOutputStreamat the end of your first case statement in Client for no apparent reason. Remove that line and you won't get the error.
I want a efficient and a fast way of sending a stop message in a socket.
I have a method that send files from one pc to another. All of the files from the sender appear on the receiver's PC. However all of the data is being written to the first file (only). The other files exist, but are empty. This happen because the receiver method doesn't know when to start writing to the next file.
Sender
public static void sendFile (final Socket sock, File source)
{
FileInputStream fileIn = null;
try
{
//Read bytes from the source file
fileIn = new FileInputStream(source);
//Write bytes to the receive
//No need to use a buffered class, we make our own buffer.
OutputStream netOut = sock.getOutputStream();
byte[] buffer = new byte[BUFFER_SIZE];
int read;
while ((read = fileIn.read(buffer)) != -1)
{
netOut.write(buffer, 0, read);
netOut.flush ();
}
//Send some stop message here
}
catch (Exception e)
{
e.printStackTrace ();
}
finally
{
if (fileIn != null)
{
try
{
fileIn.close ();
}
catch (IOException e)
{
e.printStackTrace ();
}
}
}
}
//Send files via socket
public static void sendFile (final Socket sock, File[] source)
{
for (int i = 0; i < source.length; i++)
sendFile (sock, source[i]);
}
Receiver:
public static void receiveFile (final Socket sock, File destination)
{
BufferedOutputStream out = null;
try
{
//Receive data from socket
InputStream clientInputStream = sock.getInputStream();
//Write bytes to a file
out = new BufferedOutputStream (new FileOutputStream (destination));
byte[] buffer = new byte[BUFFER_SIZE];
int read;
while (true)
{
read = clientInputStream.read(buffer);
out.write(buffer, 0, read);
out.flush ();
}
}
catch (IOException e)
{
e.printStackTrace ();
}
finally
{
if (out != null)
{
try
{
out.close ();
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
}
//Receive files via socket
public static void receiveFile (final Socket sock, File[] destination)
{
for (int i = 0; i < destination.length; i++)
receiveFile (sock, destination[i]);
}
You need to modify your send/receive protocol to include at least a minimal header before sending the file. Your header should include at least the size of the data to follow, and anything else you might want (such as file name).
I tried with a header like you suggested, but it doesn't work. The receiver still don't know when to stop(so I get EOFException). All the received data get written to the first file.
public static void sendFile (Socket sock, File source)
{
FileInputStream fileIn = null;
try
{
//Read bytes from the source file
fileIn = new FileInputStream(source);
//Write bytes to the receive
//No need to use a buffered class, we make our own buffer.
OutputStream netOut = sock.getOutputStream();
byte[] buffer = new byte[BUFFER_SIZE];
int readBytes = 0;
long fileSize = source.length();
long counter = 0;
//Send the file size
DataOutputStream objOut = new DataOutputStream (netOut);
System.out.println ("Writing: " + source.length ());
objOut.writeLong (fileSize);
objOut.flush ();
while ((counter += readBytes) < fileSize)
{
readBytes = fileIn.read(buffer);
netOut.write(buffer, 0, readBytes);
netOut.flush ();
}
fileIn.close();
}
catch (Exception e)
{
e.printStackTrace ();
}
finally
{
if (fileIn != null)
{
try
{
fileIn.close ();
}
catch (IOException e)
{
e.printStackTrace ();
}
}
}
}
[]
public static void receiveFile (Socket sock, File destination)
{
BufferedOutputStream fileOut = null;
try
{
//Receive data from socket
InputStream netIn = sock.getInputStream();
//Write bytes to a file
fileOut = new BufferedOutputStream (new FileOutputStream (destination));
byte[] buffer = new byte[BUFFER_SIZE];
int readBytes = 0;
long fileSize;
long counter = 0;
//Receive the file size
DataInputStream objIn = new DataInputStream (netIn);
fileSize = objIn.readLong ();
System.out.println ("Receiving: " + fileSize);
while (true)
{
readBytes = netIn.read (buffer);
fileOut.write (buffer, 0, readBytes);
fileOut.flush ();
counter += readBytes;
if (counter > fileSize)
break;
}
}
catch (IOException e)
{
e.printStackTrace ();
}
finally
{
if (fileOut != null)
{
try
{
fileOut.close ();
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
System.out.println ("Ending method");
}
hi this is my client program for transfering Image , while transfering the image file it is getting corrupted , not able to open that image file , i'm not able to identify the bug , can any one help me.
DataInputStream input = new DataInputStream(s.getInputStream());
DataOutputStream output = new DataOutputStream(s.getOutputStream());
System.out.println("Writing.......");
FileInputStream fstream = new FileInputStream("Blue hills.jpg");
DataInputStream in = new DataInputStream(fstream);
byte[] buffer = new byte[1000];
int bytes = 0;
while ((bytes = fstream.read(buffer)) != -1) {
output.write(buffer, 0, bytes);
}
in.close();
I assume that s is a Socket and you're attempting to transfer a file over the network? Here's an example of sending a file with sockets. It just sets up a server socket in a thread and connects to itself.
public static void main(String[] args) throws IOException {
new Thread() {
public void run() {
try {
ServerSocket ss = new ServerSocket(3434);
Socket socket = ss.accept();
InputStream in = socket.getInputStream();
FileOutputStream out = new FileOutputStream("out.jpg");
copy(in, out);
out.close();
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}.start();
Socket socket = new Socket("localhost", 3434);
OutputStream out = socket.getOutputStream();
FileInputStream in = new FileInputStream("in.jpg");
copy(in, out);
out.close();
in.close();
}
public static void copy(InputStream in, OutputStream out) throws IOException {
byte[] buf = new byte[8192];
int len = 0;
while ((len = in.read(buf)) != -1) {
out.write(buf, 0, len);
}
}