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Socket closed exception when trying to transfer a file

I am trying to transfer a file from server to client using Java and TCP, however on the client-side I am getting a socket closed exception, whereas the server has no errors when attempting to transfer the file. I am confused about this error because I did not close the socket before trying to read from it. The server accepts the connection and sends the file, but the client gets that error. Any suggestion?
The error is:
java.net.SocketException: Socket closed
Server thread's run function:
public void run() {
System.out.println("Service thread running for client at " + socket.getInetAddress() + " on port " + socket.getPort());
try {
File file = new File("hank.txt");
FileInputStream fis = new FileInputStream(file);
BufferedInputStream bis = new BufferedInputStream(fis);
OutputStream os = socket.getOutputStream();
byte[] contents;
long fileLength = file.length();
long current = 0;
long start = System.nanoTime();
while(current!=fileLength) {
int size = 1000;
if(fileLength - current >= size) {
current += size;
}
else {
size = (int)(fileLength - current);
current = fileLength;
}
contents = new byte[size];
bis.read(contents,0,size);
os.write(contents);
System.out.println("sending file..." + (current*100)/fileLength+"% complete!");
}
os.flush();
this.socket.close();
}catch(Exception e) {
e.printStackTrace();
}
}
Client receiving the file code:
System.out.println("Going to get the file...");
socket = new Socket(response.getIP().substring(1), response.getPort());
byte[] contents = new byte[10000];
FileOutputStream fos = new FileOutputStream("hank.txt");
BufferedOutputStream bos = new BufferedOutputStream(fos);
InputStream in = socket.getInputStream();
int bytesRead = 0;
System.out.println("Starting to read file...");
while((bytesRead = is.read(contents))!=-1) { //the error points to this lin
bos.write(contents,0,bytesRead);
}
bos.flush();
bos.close();
in.close();
//
socket.close();

Input stream for this socket is available in variable in
InputStream in = socket.getInputStream();
So
Change is.read(contents)) to in.read(contents))

Android sending file name via socket communication [duplicate]

This question already has answers here:
How do I send file name with file using sockets in Java? [duplicate]
(3 answers)
Closed 6 years ago.
I am able to send Files through socket and receive on other ends . Now i want to send even file name so that after receiving file and saving file from socket i can save the name of file. What to add in client to send filename and in server to receive filename thanks in advance to all
Client.java
try {
clientSocket = new Socket(targetIP, port);
os = clientSocket.getOutputStream();
PrintWriter pw = new PrintWriter(os);
InputStream is = clientSocket.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
signalActivity("About to start handshake");
byte[] buffer = new byte[4096];
FileInputStream fis = new FileInputStream(fileToSend);
BufferedInputStream bis = new BufferedInputStream(fis);
// long BytesToSend = fileToSend.length();
while(true)
{
int bytesRead = bis.read(buffer, 0, buffer.length);
if(bytesRead == -1)
{
break;
}
//BytesToSend = BytesToSend - bytesRead;
os.write(buffer,0, bytesRead);
os.flush();
}
fis.close();
bis.close();
br.close();
isr.close();
is.close();
pw.close();
os.close();
clientSocket.close();
} catch (IOException e) {
}
catch(Exception e)
{
}
Server.java
try {
welcomeSocket = new ServerSocket(port);
while(true && serviceEnabled)
{
socket = welcomeSocket.accept();
InputStream is = socket.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
OutputStream os = socket.getOutputStream();
PrintWriter pw = new PrintWriter(os);
String inputData = "";
// String savedAs = "WDFL_File_" + System.currentTimeMillis();
//save the original name and extention
File file = new File(saveLocation, savedAs);
byte[] buffer = new byte[4096];
int bytesRead;
FileOutputStream fos = new FileOutputStream(file);
BufferedOutputStream bos = new BufferedOutputStream(fos);
while(true)
{
bytesRead = is.read(buffer, 0, buffer.length);
if(bytesRead == -1)
{
break;
}
bos.write(buffer, 0, bytesRead);
bos.flush();
}
bos.close();
socket.close();
//Start writing to file
}
} catch (IOException e) {
}
catch(Exception e)
{
}

Your client should send the file name first. After that the contents of the file.
The server should read the file name first so the following content of the file can be saved under the same file name.

Issues sending jpg-image over java socket using datainput/-outputstream

I wish to send a JPG-image from a client to a server over a TCP socket connection. I convert the file to a byte array in the client then send it to the server after having sent the array length. The server reads the data one byte at a time from the socketinputstream to a new bytearray which is then written to a jpg-file. The data however is corrupted and this image cannot be viewed. Below is core java code for client and server.
Client:
Socket s = new Socket("localhost", 666);
DataOutputStream dos = new DataOutputStream(s.getOutputStream());
String imgPath = "C:/Users/huehuehue/Documents/Uni/D0036D/prick1.JPG";
File file = new File(imgPath);
byte[] b = new byte[(int) file.length()];
FileInputStream fis = new FileInputStream(file);
fis.read(b);
fis.close();
dos.writeInt((int) file.length());
dos.flush();
dos.write(b, 0, b.length);
dos.flush();
Server:
ServerSocket serverSocket = new ServerSocket(666);
Socket connect = serverSocket.accept();
DataInputStream dis = new DataInputStream(connect.getInputStream());
File file = new File("C:/Users/huehuehue/Documents/Uni/D0036D/PLAYERprick.JPG");
FileOutputStream fos = new FileOutputStream(file);
int arrlen = dis.readInt();
byte[] b = new byte[arrlen];
int i = 0;
for(i = 0; i < arrlen; i++) {
b[i] = dis.readByte();
i++;
}
fos.write(b, 0 , b.length);
I can't see why this wouldn't work and any help or suggestions is greatly appreciated.

int arrlen = dis.readInt();
byte[] b = new byte[arrlen];
int i = 0;
for(i = 0; i < arrlen; i++) {
b[i] = dis.readByte();
i++;
}
You're incrementing i twice so you're ignoring half the input, and writing what you don't ignore into the wrong slots. Fortunately there is an easier way, which is also much more efficient:
int arrlen = dis.readInt();
byte[] b = new byte[arrlen];
dis.readFully(b);
NB fis.read(b); isn't valid. You can't assume it fills the buffer. You should use DataInputStream.readFully() here too.

You need to match both ends of the socket and your client doesn't fill your byte[] fully; instead your client could send each byte as it reads it. And, since Java provides BufferedInputStream you don't have to manually use and tweak a byte[] buffer directly. Instead you could do something like,
Socket s = new Socket("localhost", 666);
String imgPath = "C:/Users/huehuehue/Documents/Uni/D0036D/prick1.JPG";
File file = new File(imgPath);
try (InputStream is = new BufferedInputStream(new FileInputStream(file));
DataOutputStream dos = new DataOutputStream(s.getOutputStream());) {
dos.writeLong(file.length()); // <-- remember to read a long on server.
int val;
while ((val = is.read()) != -1) {
dos.write(val);
}
dos.flush();
}
Also, your server could use the similar BufferedOutputStream to get the benefit of a buffer like
ServerSocket serverSocket = new ServerSocket(666);
File file = new File("C:/Users/huehuehue/Documents/Uni/D0036D/PLAYERprick.JPG");
try (Socket s = serverSocket.accept();
DataInputStream dis = new DataInputStream(
s.getInputStream());
OutputStream fos = new BufferedOutputStream(
new FileOutputStream(file));) {
long arrlen = dis.readLong();
for (long i = 0; i < arrlen; i++) {
fos.write(dis.read());
}
fos.flush();
}
without having to manually manage it. Notice the above use BufferedInputStream and BufferedOutputStream to manage the buffering as an optimization. You could remove them and read and write directly from the File streams.

Showing corrupted but working in java but not in android

I have a server client file transfer program which works fine in java .but i copied it and changed the file location d:/ to environm.....
The problem is the filesize is lesser than sending one, hence its shown as corrupted.. Any idea .
SERVER SIDE
public class Server
{
// create socket
long start = System.currentTimeMillis();
int bytesRead;
int current = 0;
while(true)
{
ServerSocket servsock = new ServerSocket(13000);
System.out.println("Main Waiting...");
Socket socket = servsock.accept();
System.out.println("Accepted connection : " + socket);
DataInputStream in = new DataInputStream(new BufferedInputStream(socket.getInputStream()));
long filesize = new Long(in.readLong());
System.out.println("received Size:"+filesize);
// read file name
String fname=in.readUTF();
System.out.println("server : file name: "+fname);
String prefix=fname.substring(0,fname.lastIndexOf('.')).trim();
String suffix=fname.substring(fname.lastIndexOf('.'),fname.length()).trim();
String file = prefix + suffix;
System.out.println("received name:"+file);
File f=new File("F:/Users/achu/Desktop/"+ file);// changed this in android
f.createNewFile();
// receive file
byte [] mybytearray = new byte [(int)(filesize)];
InputStream is = socket.getInputStream();
FileOutputStream fos = new FileOutputStream(f);
BufferedOutputStream bos = new BufferedOutputStream(fos);
bytesRead = is.read(mybytearray,0,mybytearray.length);
current = bytesRead;
do {
System.out.println("current"+current);
bytesRead =
is.read(mybytearray, current, (mybytearray.length-current));
if(bytesRead >= 0) current += bytesRead;
} while(current<filesize && bytesRead >-1);
bos.write(mybytearray, 0 , current);
bos.flush();
long end = System.currentTimeMillis();
System.out.println(end-start);
bos.close();
is.close();
socket.close();
servsock.close();
}
}
CLIENT SIDE
public class Client
{
Socket socket=new Socket("101.59.43.58",13000);
System.out.println("Connectedddd");
DataOutputStream out = new DataOutputStream(socket.getOutputStream());
File file = new File("d:/my.pdf");
out.writeLong(file.length());
out.flush();
out.writeUTF(file.getName());
byte [] mybytearray = new byte [(int)file.length()];
FileInputStream fis = new FileInputStream(file);
BufferedInputStream bis = new BufferedInputStream(fis);
bis.read(mybytearray,0,mybytearray.length);
System.out.println("Send:"+mybytearray.length);
OutputStream ous = socket.getOutputStream();
System.out.println("Sending...");
ous.write(mybytearray,0,mybytearray.length);
ous.flush();
bis.close();
ous.close();
System.out.println("closing socket...");
socket.close();
}

Socket closed issues

I have a server and client connection using sockets to transfer files, but if I want to be able to send strings to the server from the client upon user JButton actions, it throws socket closed errors (Because I used dos.close() in the Sender() constructor). The problem is, if I don't use dos.close(), the client program won't run/init the UI frame. What am I doing wrong? I need to be able to send files when the program first runs then send data later.
Sender:
public Sender(Socket socket) {
List<File> files = new ArrayList<File>();
files.add(new File(Directory.getDataPath("default.docx")));
files.add(new File(Directory.getDataPath("database.db")));
try {
BufferedOutputStream bos = new BufferedOutputStream(socket.getOutputStream());
DataOutputStream dos = new DataOutputStream(bos);
dos.writeInt(files.size());
for (File file : files) {
dos.writeLong(file.length());
dos.writeUTF(file.getName());
FileInputStream fis = new FileInputStream(file);
BufferedInputStream bis = new BufferedInputStream(fis);
int theByte = 0;
while ((theByte = bis.read()) != -1) {
bos.write(theByte);
}
bis.close();
}
dos.close(); // If this is disabled, the program won't work.
} catch (Exception e) {
e.printStackTrace();
}
}
Downloader:
public static byte[] document;
public Downloader(Socket socket) {
try {
BufferedInputStream bis = new BufferedInputStream(socket.getInputStream());
DataInputStream dis = new DataInputStream(bis);
int filesCount = dis.readInt();
for (int i = 0; i < filesCount; i++) {
long size = dis.readLong();
String fileName = dis.readUTF();
if (fileName.equals("database.db")) {
List<String> data = new ArrayList<String>();
BufferedReader reader = new BufferedReader(new InputStreamReader(bis));
String line;
while ((line = reader.readLine()) != null) {
if (line.trim().length() > 0) {
data.add(line);
}
}
reader.close();
parse(data);
} else if (fileName.equals("default.docx")) {
ByteArrayOutputStream bos = new ByteArrayOutputStream();
for (int x = 0; x < size; x++) {
bos.write(bis.read());
}
bos.close();
document = bos.toByteArray();
}
}
//dis.close();
} catch (Exception e) {
e.printStackTrace();
}
}

Your first receive loop in the client terminates at EOS, which only happens when you close the socket in the sender, which you don't want to do. You're sending the length ahead of the file in each case so the receiving code should look like this in both cases:
long total = 0;
while ((total < size && (count = in.read(buffer, 0, size-total > buffer.length ? buffer.length : (int)(size-total))) > 0)
{
total += count;
out.write(buffer, 0, count);
}
out.close();
That loop reads exactly size bytes from the socket input stream and writes it to the OutputStream out, whatever out happens to be: in the first case, a FileOutputStream, in the second, a ByteArrayOutputStream.