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Sending multiple files through network - time to time

I have program that create screenshots and some txt files and send it throught socket. But every time I must connect to server to send data. (connect -> send -> disconnect)
current solution:
server:
public class Main {
public static void main(String[] args) {
try(ServerSocket serverSocket = new ServerSocket(5000)){
while(true){
new Echoer(serverSocket.accept()).start();
}
}catch(IOException e){
System.out.println("Server exception " + e.getMessage());
}
}
}
public class Server extends Thread {
private Socket socket;
public Server(Socket socket) {
this.socket = socket;
System.out.println(this.getName() + " -> " + "CONNECTED");
}
#Override
public void run() {
try {
String main = "tests";
DataInputStream dis;
BufferedInputStream bis;
//while (true) {
bis = new BufferedInputStream(socket.getInputStream());
dis = new DataInputStream(bis);
String directory = dis.readUTF(); //read directory
String dirPath = main + "/" + directory; //main dir
String tmp = dirPath;
//create directory
if (!new File(dirPath).exists()) {
new File( dirPath).mkdir();
new File( dirPath + "/o").mkdir();
new File( dirPath+ "/n").mkdir();
}
int fileCount = dis.readInt();
File[] files = new File[fileCount]; //array for files
for (File f : files) {
long fileLength = dis.readLong();
String fileName = dis.readUTF();
dirPath = tmp;
f = new File(dirPath + "/" + fileName);
FileOutputStream fos = new FileOutputStream(f);
BufferedOutputStream bos = new BufferedOutputStream(fos);
for (int j = 0; j < fileLength; j++) bos.write(bis.read());
bos.close();
fos.close();
}
dis.close();
System.out.println("Received file");
//}
} catch (IOException e) {
System.out.println("->" + e.getMessage());
}
}
}
client
public class Connection {
private String path;
private List<String> files;
private Socket socket;
private Config config;
#SneakyThrows
public Connection(String path, List<String> files){
this.config = LoadConfig.getInstance().getConfig();
this.path = path;
this.files = files;
//ip, port from config
socket = new Socket(
config.getServer().getUrl(),
config.getServer().getPort()
);
}
public void send() {
BufferedOutputStream bos = null;
DataOutputStream dos = null;
try {
bos = new BufferedOutputStream(socket.getOutputStream());
dos = new DataOutputStream(bos);
//map paths to files
List<File> filesList = files.stream().map(e -> new File(path + "/"+ e)).collect(Collectors.toList());
dos.writeUTF(ComputerInfo.userName()); //send user name
dos.writeInt(filesList.size()); //send amount of elements
for(File f: filesList){
long length = f.length(); //one file size
dos.writeLong(length);
String name = f.getName();
dos.writeUTF(name); //send file name
FileInputStream fis = new FileInputStream(f);
BufferedInputStream bis = new BufferedInputStream(fis);
int theByte = 0;
while((theByte = bis.read()) != -1) bos.write(theByte);
bis.close();
}
dos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
I want to send files from time to time, depending on what the algorithm returns. It means send files in irregular times. It means send 1 file wait 5 min sent 4 files wait 1s send 3 ... But I don't know how to do it. I created also client using blockingqueue and other parts of program add data to it.
public class Connection implements Runnable {
private Socket socket;
private Config config;
protected BlockingQueue<Data> queue;
private BufferedOutputStream bos;
private DataOutputStream dos;
#SneakyThrows
public Connection(BlockingQueue<Data> queue) {
this.config = LoadConfig.getInstance().getConfig();
socket = new Socket(
config.getServer().getUrl(),
config.getServer().getPort()
);
this.queue = queue;
bos = new BufferedOutputStream(socket.getOutputStream());
}
#SneakyThrows
public void run() {
dos = new DataOutputStream(bos);
while (true) {
if (queue.isEmpty()) {
continue;
} else {
//this.send();
System.out.println(queue.size());
}
}
}
#SneakyThrows
private void send() {
Data loadData = queue.take();
List<File> filesList = loadData.getList().stream().map(e -> new File(loadData.getPath() + "/" + e)).collect(Collectors.toList());
dos.writeUTF(ComputerInfo.userName());
dos.writeInt(filesList.size());
for (File f : filesList) {
long length = f.length();
dos.writeLong(length);
String name = f.getName();
dos.writeUTF(name);
FileInputStream fis = new FileInputStream(f);
BufferedInputStream bis = new BufferedInputStream(fis);
int theByte = 0;
while ((theByte = bis.read()) != -1) bos.write(theByte);
bis.close();
fis.close();
}
dos.close();
}
Any suggestion how to do it?

Sending a string and file into InputStream

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;

Send files with java socket

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

How to close Output/Input and FileOutput/Input streams properly?

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.

File transfer Server to client - java

I am trying to write the server client file transfer program in java.
Role of Server:-
a) Serve a file to a client (one).
b) Server will send file 1 byte at a time.
c) Should be able to send the file more than once.
Role of Client:-
a) Client downloads a file
b) Client should buffer the file before writing to disk( <= 100kb) I.e. buffer 100KB and write to disk then repeat this till 1MB
I wrote the code to transfer the file from Server to Client but there seem to have some issues with the program. Server starts sending the data but its lost in the transaction. Also the content of file to be transferred is erased. As I couldn't see any specific error on console so I couldn't figure out the bug. If anyone guide me whether this approach is correct or if not, please suggest proper changes.
*Server*
public class Server {
public static void main(String[] args) throws IOException {
ServerSocket serverSocket = null;
Socket socket = null;
InputStream inputStream = null;
FileOutputStream fileOutputStream = null;
BufferedOutputStream bufferedOutputStream = null;
int sizeBuffer = 0;
try{
try {
serverSocket = new ServerSocket(55555);
} catch (IOException ex) {
System.out.println("Error: Unable to Connect to Server ");
}
System.out.println("Created Socket");
try {
socket = serverSocket.accept();
} catch (IOException ex) {
System.out.println("Error: Unable to connect to client ");
}
System.out.println("Accepted Client Connection ");
try {
inputStream = socket.getInputStream();
sizeBuffer = socket.getReceiveBufferSize();
System.out.println("Size of Buffer " + sizeBuffer);
} catch (IOException ex) {
System.out.println("Error: unable to ger socket input stream ");
}
try {
fileOutputStream = new FileOutputStream("D:/ServerFile.txt");
bufferedOutputStream = new BufferedOutputStream(fileOutputStream);
} catch (FileNotFoundException ex) {
System.out.println("File not found. ");
}
byte[] bytes = new byte[sizeBuffer];
int count;
while ((count = inputStream.read(bytes)) > 0) {
bufferedOutputStream.write(bytes, 0, count);
}
System.out.println("Done");
}// end of first try
finally{
bufferedOutputStream.flush();
bufferedOutputStream.close();
inputStream.close();
socket.close();
serverSocket.close();
}
}
}
And here is client side code !
*Client*
public class Client {
public static void main(String[] args) throws IOException {
FileInputStream fileInputStream = null;
BufferedInputStream bufferedInputStream = null;
BufferedOutputStream bufferedOuptputStream = null;
Socket socket = null;
int count;
try{
try {
socket = new Socket("127.0.0.1", 55555);
} catch (IOException ex) {
System.out.println("Error: Unable to create Socket ");
}
File file = new File("D:/ClientFile.txt");
long fileLength = file.length();
System.out.println(fileLength);
if ( Integer.MAX_VALUE < fileLength ) {
System.out.println("Error: Exceeded the size of transfer");
}
byte[] bytes = new byte[(int) fileLength];
try{
fileInputStream = new FileInputStream(file);
}catch (IOException ex){
System.out.println("Error: Unable to open fileInputStream");
}
bufferedInputStream = new BufferedInputStream(fileInputStream);
bufferedOuptputStream = new BufferedOutputStream(socket.getOutputStream());
while ((count = bufferedInputStream.read(bytes)) > 0) {
bufferedOuptputStream.write(bytes, 0, count);
}
}
finally{
bufferedOuptputStream.flush();
bufferedOuptputStream.close();
fileInputStream.close();
bufferedInputStream.close();
socket.close();
}
}
}