I have written a code for Server and Client in Java. Clients are able to download the files from the server and the server should also be able to provide files to clients Concurrently.
For this purpose I have used multithreading in Server.
It is working perfectly fine for one client but while using threads for every client it seems to be not working properly in my Code.
As the files are not getting downloaded correctly, are corrupt and are of varying sizes for different clients.
After accepting from a client, I am creating a new Thread for serving it the file
Code for server -
public static void send(String pathname) throws IOException, NoSuchAlgorithmException, NoSuchPaddingException
{
try
{
System.out.println("....");
byte[] buf = new byte[1024];
OutputStream os = sock.getOutputStream();
//PrintWriter writer = new PrintWriter(os);
System.out.println("...11.");
BufferedOutputStream out = new BufferedOutputStream(os, 1024);
int i=0;
System.out.println("hi1");
File fp = new File(pathname);
System.out.println("hi2");
RandomAccessFile ra = new RandomAccessFile(fp,"r");
System.out.println("hi3");
long bytecount=1024;
////////////////
while((i=ra.read(buf, 0, 1024)) != -1)
{
System.out.println("hi");
bytecount += 1024;
System.out.println("hi6");
out.write(buf, 0, i);
System.out.println("hi7");
out.flush();
}
System.out.println("bye");
//os.flush();
//out.close();
ra.close();
//sock.close();
}
catch(IOException ex)
{
}
}
And code for client for file receiving is
public void run() {
try{
byte[] b = new byte[1024];
int len = 0;
long bytcount = 1024;
File fp = new File(path);
RandomAccessFile ra=new RandomAccessFile(fp,"rw");
ra.seek(0);
InputStream is = sock.getInputStream();
BufferedReader reader=new BufferedReader(new InputStreamReader(is));
while ((len = is.read(b, 0, 1024)) != -1) {
bytcount = bytcount + 1024;
//decrypt
ra.write(b, 0, len);
}
//is.close();
//ra.close();
//sock.close();
}
catch(IOException ex){
ex.printStackTrace();
}
// throw new UnsupportedOperationException("Not supported yet.");
}
}
I am not getting out what's wrong here. Please help
Many many thanx in advance
send is static, which suggests to me that you have only one socket, named sock, or the following would not compile.
public static void send(String pathname) throws IOException, NoSuchAlgorithmException, NoSuchPaddingException
{
try
{
System.out.println("....");
byte[] buf = new byte[1024];
OutputStream os = sock.getOutputStream();
//PrintWriter writer = new PrintWriter(os);
System.out.println("...11.");
If that is the case, it's hard to see how delivery to >1 client will be reliable. You will surely need one socket per client to perform concurrent deliveries? More code is needed to be sure of this, but it looks like the design of socket handling may need to be revised.
Your first problem is that you are using an OutputStream on the server and a Reader on the client. the client should be using InputStreams, not Readers.
Related
I am using Commons-IO to read and write from Socket. Things all works till payload size is either 1448/2896 max.
Below is the code snippet. Really unsure how to handle it.
Checked system buffer size too
$ cat /proc/sys/net/ipv4/tcp_wmem
4096 16384 4194304
public static void usingCommonsIO(){
Socket socket = null;
try {
socket = new Socket(serverIP, 55000);
IOUtils.write(request.getBytes(), socket.getOutputStream());
System.out.println("Message Sent....");
StringBuilder response = new StringBuilder();
String resp =IOUtils.toString(socket.getInputStream(), "UTF-8");
System.out.println(resp);
} catch (IOException e) {
e.printStackTrace();
}
}
Alternatively tried using DataInputStream but no luck. Code snipped is below.
public static void usingDataIOStream(String requestStr){
Socket socket = null;
try {
socket = new Socket("192.168.1.6", 55000);
System.out.println("Request Length -:" + request.length());
DataOutputStream out = new DataOutputStream(socket.getOutputStream());
out.write(requestStr.getBytes("UTF-8"), 0, requestStr.length());
out.flush();
System.out.println("Message Sent....");
DataInputStream din = new DataInputStream(socket.getInputStream());
byte[] response = new byte[16*1024];
int responseLength = din.read(response);
System.out.println("Response -:" + new java.lang.String(response, 0, responseLength));
} catch (IOException e) {
e.printStackTrace();
}
}
Confusing part is that the same code works with only 1448 bytes sometimes and max of 2896 bytes sometimes. There are no specific patterns.
Update 1
To simulate it, tried writing Server socket on my own and code is as below. Strange thing noticed with this is, on first request payload of size 6500 was read and received properly. Connection Reset from second request onwards. Am I missing something here?
public static void usingBAOS() throws IOException {
server = new ServerSocket(port);
Socket socket = null;
DataInputStream din = null;
DataOutputStream dos = null;
while (true) {
System.out.println("Waiting for Client...");
try {
// Accepting Client's connection
socket = server.accept();
System.out.println("Connnected to client " + socket.getInetAddress());
din = new DataInputStream(socket.getInputStream());
// Read request payload from Socket
String requestString = readRequest(din);
System.out.println("Request Read.....");
System.out.println("Writing Response.....");
// Writing response to socket
dos = writeResponse(socket, requestString);
} catch (IOException e) {
e.printStackTrace();
}finally {
//close resources
din.close();
System.out.println("InputStream is closed......");
dos.close();
System.out.println("OutputStream is closed......");
socket.close();
System.out.println("Socket is closed......");
}
}
}
private static DataOutputStream writeResponse(Socket socket, String requestString) throws IOException {
String responseString = "Hi Client" + requestString;
DataOutputStream dos = new DataOutputStream(socket.getOutputStream());
//write object to Socket
dos.write(responseString.getBytes(),0, responseString.getBytes().length);
dos.flush();
return dos;
}
private static String readRequest(DataInputStream din) throws IOException {
byte[] response = new byte[16*1024];
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int n = 0;
boolean read = true;
while(read){
n = din.read(response);
baos.write(response, 0, n);
if(baos.toString().length() == n){
read = false;
}
}
baos.flush();
String requestString = baos.toString();
return requestString;
}
Although this question is old at the time of writing this answer I'm putting this here for others in case it solves their problem. I encountered the same issue when using buffered data input and output streams on Android 8.0 devices where I had naively assumed that doing this:
int len = 2304;
byte[] data = new byte[len];
inputStream.read(data, 0, len);
would read all the data I sent down the socket. But as suggested by #Kayaman in the comments, this does not guarantee that len bytes of data are actually read from the buffer even if there are bytes available. In fact, this is in the documentation:
public final int read(byte[] b, int off, int len) throws IOException
Reads up to len bytes of data from the contained 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, possibly zero. The number of bytes actually read is returned as an integer.
In fact, if it doesn't read all the data, the only way to tell is to capture the returned value. My solution was then to monitor the amount of bytes actually read from the stream and just call read() in a loop as:
int i = 0;
len = 2304;
byte[] data = new byte[len];
while (i < len)
{
i += socket.inputStream.read(data, i, len - i);
}
Hope this helps someone.
I am new to XML-RPC and may be my question is silly but I can't find any information to help me for that...
So here it is : I am using this java code to send a XML file through a XML-RPC request using HTTP.
public static void sendXML(String file, String host, String port, String url) throws IOException{
Socket socket = new Socket(host, Integer.parseInt(port));
OutputStream out = socket.getOutputStream();
InputStream in = socket.getInputStream();
StringBuffer header = new StringBuffer();
header.append("POST "+url+" HTTP/1.0\n");
header.append("Content-Type: text/xml\n");
header.append("Content-Length: "+(new File(file).length()+2)+"\n");
header.append("\n");
byte[] buffer = header.toString().getBytes("UTF-8");
out.write(buffer);
InputStream src = new FileInputStream(file);
buffer = new byte[1024];
int b = 0;
while((b = src.read(buffer)) >= 0){
out.write(buffer, 0, b);
}
buffer = "\n\n".getBytes("UTF-8");
out.write(buffer);
out.close();
src.close();
in.close();
out.flush();
socket.close();
}
In this code, the XML file is already created, containing the method called and all the parameters.
This solution works fine but I am asking to make it compatible for a HTTPS protocol.
Do I need to only change the line
header.append("POST "+url+" HTTP/1.0\n");
in
header.append("POST "+url+" HTTPS/1.0\n");
?
Or should I use the Apache library https://ws.apache.org/xmlrpc/client.html ?
Or may be is there any simpler solution in java language ?
Thank you all for your help
I'm doing simple Client-Server applications which copying file from client to server and vice versa. I'm using Sockets of course. Apps shows Client menu with some options to choose: 1. Make Copy on sever 2. Get fileCopy from Server etc.
The issue is when I'm choosing first option, I can't do second one. I read about this exception, but i have no idea how to solve this problem. I'm looking forward for your ideas.
There is part of clientside code:
public Client(String host, int port) {
try {
s = new Socket(host, port);
System.out.println("Witaj w programie");
boolean finished = false;
Scanner sc = new Scanner(System.in);
while(!finished){
System.out.println("\n\n1.Zrob kopie zapasowa pliku");
System.out.println("2. Przywroc kopie");
System.out.println("0.Zakoncz");
char c = sc.nextLine().charAt(0);
switch(c){
case '1':
this.sendMessage(1);
makeCopy(s);
//s.close();
break; ...
sendMessage method code:
public void sendMessage(int message_id) throws IOException{
oos = new ObjectOutputStream(s.getOutputStream());
ois = new ObjectInputStream(s.getInputStream());
oos.writeInt(message_id);
oos.flush();
}
and makeCopy method code:
private void makeCopy(Socket clientSock) throws IOException {
File file = new File("D:\\klient\\doKopii.bmp");
DataOutputStream dos = new DataOutputStream(clientSock.getOutputStream());
FileInputStream fis = new FileInputStream(file);
byte[] buffer = new byte[4096];
while (fis.read(buffer) > 0) {
dos.write(buffer);
}
fis.close();
dos.close();
}
Download copy from Server code:
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();
}
I am aware of that this does not work because of DataOutputStream closing which means socket is also closed. I deleted this line, but after choosing one option then second (when first one has done), application just freezes.
oos = new ObjectOutputStream(s.getOutputStream());
ois = new ObjectInputStream(s.getInputStream());
public void sendMessage(int message_id) throws IOException{
oos.writeInt(message_id);
}
make oos and ois as instance variables and make sure that they are instantiated only for one single time.
why you have to get a dataoutput stream seperately you can send byte array in same objectoutputstream
private void makeCopy(Socket clientSock) throws IOException {
File file = new File("D:\\klient\\doKopii.bmp");
FileInputStream fis = new FileInputStream(file);
byte[] buffer = new byte[4096];
while (fis.read(buffer) > 0) {
oos.write(buffer);
}
}
this is not very good coding practise bt maybe u should try this approach
There are several problems here.
You need to send the file length ahead of the file, and read exactly that many bytes at the receiver, as shown in this answer.
Don't mix stream types, and don't keep creating new streams. Use the same ObjectInputStream/ObjectOutputStream pair for the life of the socket, at both ends.
I need some help from you guys. I'm new at networking and try to send a text file from a client to a server, and then back to the client again.
The code below works fine for the first step, sending the text file from client to server. The server receives the file, and adds something to it (not in this code).
Then my problem starts: How can I make the server send the text file back to client again, and have client receive it?
I really don't know how to do this. And also, can you tell me if I need to add a while loop to my code, if I want to send files back and forth many times?
Thanks
Client (Starts with sending a text file to server)
public class TClient {
public static void main(String[] args) throws IOException {
Socket socket = new Socket("localhost", 11111);
InputStream in = new FileInputStream("send.txt");
OutputStream out = socket.getOutputStream();
byte[] buf = new byte[8192];
int len = 0;
while ((len = in.read(buf)) != -1) {
out.write(buf, 0, len);
}
out.close();
in.close();
}
}
Server (starts with receiving a text file from client)
public class TServer {
public static void main(String[] args) throws IOException {
ServerSocket ss = new ServerSocket(11111);
Socket socket = ss.accept();
InputStream in = socket.getInputStream();
OutputStream out = new FileOutputStream("receive.txt");
byte[] buf = new byte[8192];
int len = 0;
while ((len = in.read(buf)) != -1) {
out.write(buf, 0, len);
}
out.close();
in.close();
}
}
Hello everyone ,
I am trying to develop the application for transfering/sending the file like SKYPE works.So I am using socket for transfering file from one computer(client) to another computer(client) .I am able to transfer file from one client to server using this. code.But when I try to send the same file from server to second client.It is transfering with 0 byte also give socket close exception so I try to create new socket object at client side.So Now the Exception not coming but file not transfering to client.After debugging I found that the file is successfully sent to client by server but at client side socket is not able to read the data and waiting for data.I can’t find any better solution.If anyone knows anything about this Please tell me.If you have any other solution for file transfer than also tell me.Thanks in advance
Below is my code
Server code:
public class ChatServer
{
serversocket = new ServerSocket(1436);
thread = new Thread(this);
thread.start();
/*************Thread Implementation***************/
public void run()
{
/*********Accepting all the client connections and create a seperate thread******/
while(thread != null)
{
try
{
/********Accepting the Server Connections***********/
socket = serversocket.accept();
/******* Create a Seperate Thread for that each client**************/
chatcommunication = new ChatCommunication(this,socket);
thread.sleep(THREAD_SLEEP_TIME);
}
catch(InterruptedException _INExc) { ExitServer(); }
catch(IOException _IOExc) { ExitServer(); }
}
}
protected void SendGroupFile(Socket ClientSocket, String FileName,String GroupName,String UserName) throws IOException
{
try
{
// receive file from Client
byte [] mybytearray = new byte [filesize];
InputStream is = socket.getInputStream();
FileOutputStream fos = new FileOutputStream(Filepath);
BufferedOutputStream bos = new BufferedOutputStream(fos);
int bytesRead = is.read(mybytearray,0,mybytearray.length);
current = bytesRead;
do {
bytesRead =is.read(mybytearray, current, (mybytearray.length-current));
System.out.println("Reading Bytes server"+bytesRead);
if(bytesRead >= 0)
current += bytesRead;
} while(bytesRead > -1);
bos.write(mybytearray,0,current);
bos.flush();
bos.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/***** Function To Send a File to Client **********/
protected void SendGroupFileClient(Socket ClientSocket, String FileName,String GroupName,String UserName)
{
try {
int m_userListSize = userarraylist.size();
clientobject = GetClientObject(GroupName);
if(clientobject != null)
for(G_ILoop = 0; G_ILoop < m_userListSize; G_ILoop++)
{
clientobject = (ClientObject) userarraylist.get(G_ILoop);
if((clientobject.getGroupName().equals(GroupName)) && (!(clientobject.getUserName().equals(UserName))))
{
{
File myFile = new File (Filepath);
byte [] mybytearray = new byte [(int)myFile.length()];
FileInputStream fis = new FileInputStream(myFile);
BufferedInputStream bis = new BufferedInputStream(fis);
bis.read(mybytearray,0,mybytearray.length);
os = socket.getOutputStream();
System.out.println("Sending...");
os.write(mybytearray,0,mybytearray.length);
os.flush();
os.close();
}
}catch(IOException _IOExc)
{
_IOExc.printStackTrace();
}
}
}
ChatCommunication .java
public class ChatCommunication implements Runnable,CommonSettings
{
Thread thread;
Socket socket;
DataInputStream inputstream;
String RFC;
ChatServer Parent;
/********Initialize the Socket to the Client***********/
ChatCommunication(ChatServer chatserver,Socket clientsocket)
{
Parent = chatserver;
socket = clientsocket;
try
{
inputstream = new DataInputStream(new BufferedInputStream(socket.getInputStream()));
}catch(IOException _IOExc) { }
thread = new Thread(this);
thread.start();
}
public void run()
{
while(thread != null)
{
try {
RFC = inputstream.readLine();
if(RFC.startsWith("FILEGRUP"))
{
Parent.SendGroupFile(socket,RFC.substring(9,RFC.indexOf("!")),RFC.substring(RFC.indexOf("!")+1,RFC.indexOf("*")),RFC.substring(RFC.indexOf("*")+1));
}
if(RFC.startsWith("FILEGET"))
{
Parent.SendGroupFileClient(socket,RFC.substring(8,RFC.indexOf("!")),RFC.substring(RFC.indexOf("!")+1,RFC.indexOf("*")),RFC.substring(RFC.indexOf("*")+1));
}
}catch(Exception _Exc)
{
Parent.RemoveUserWhenException(socket);QuitConnection();
}
}
}
Client code
class Client extends JFrame
{
ServerName="192.168.1.103";
ServerPort=1436;
Client()
{
socket = new Socket(ServerName,ServerPort);
SendGroupFileToServer(Filepath,SelectedGroup);
}
/*******Function To Send File To Server and receiving the file ***********/
protected void SendGroupFileToServer(String FileName, String ToGroup)
{
try {
dataoutputstream.writeBytes(FileName.concat("!").concat(ToUser)+"\r\n");
//send file to sever
File myFile = new File (FileName.substring(9));
byte [] mybytearray = new byte [(int)myFile.length()];
FileInputStream fis = new FileInputStream(myFile);
BufferedInputStream bis = new BufferedInputStream(fis);
bis.read(mybytearray,0,mybytearray.length);
OutputStream os = socket.getOutputStream();
System.out.println("Sending...");
os.write(mybytearray,0,mybytearray.length);
os.flush();
os.close();
System.out.println("File successfully Sended to server");
}catch(IOException _IoExc) { QuitConnection(QUIT_TYPE_DEFAULT);}
try {
socket1 = new Socket(ServerName,ServerPort); //Creating new Socket
dataoutputstream = new DataOutputStream(socket1.getOutputStream());
dataoutputstream.writeBytes("FILEGET"+FileName.concat("!").concat(ToGroup+"*"+UserName)+"\r\n"); //sending string to server
} catch (IOException e1) {
e1.printStackTrace();
}
// receive file sended by server
byte [] mybytearray = new byte [filesize];
InputStream is;
try {
is = socket1.getInputStream();
FileOutputStream fos = new FileOutputStream(Filepath);
BufferedOutputStream bos = new BufferedOutputStream(fos);
int bytesRead = is.read(mybytearray,0,mybytearray.length);
current = bytesRead; //up to this working fine
do {
bytesRead =is.read(mybytearray, current, (mybytearray.length-current)); //not reading the file data sent by server just waiting and not go ahead
if(bytesRead >= 0)
current += bytesRead;
} while(bytesRead > -1);
bos.write(mybytearray,0,current);
bos.flush();
bos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
There are so many problems here that it is difficult to know where to start.
The thread.sleep() in the accept() loop is literally a waste of time. It serves no useful purpose except possibly to throttle the rate at which clients are accepted. If that wasn't your intention, don't do it.
All you are doing when you catch an exception is exiting the server without even printing the exception message. So when something goes wrong, as it is here, you can't possibly know what it was. Don't do that.
readLine() returns null at EOS, on which you must close the socket, stop reading, and exit the thread. You aren't testing that, and you are therefore omitting all three of those required steps. Don't do that.
You are constructing a DataInputStream around a BufferedInputStream for use when reading commands, but you aren't passing it to the methods that process those commands. You are just passing the socket. You are therefore losing data. Don't do that. Every part of the program must use the same input stream or reader for the socket.
You are reading the entire file into memory. This (a) assumes the file size fits into an int; (b) does not scale to large files; (c) wastes space, and (d) adds latency. Don't do that.
You are ignoring the result of the read() into that buffer and assuming it was filled. You can't do that. The correct way to copy streams in Java is shown below. This works with a buffer of any size, e.g. 8192, for an input of any length, and doesn't require you to buffer the entire input into memory. You can use this loop at both the client when sending the file and at the server when receiving it.
while ((count = in.read(buffer)) > 0)
{
out.write(buffer, 0, count);
}
Similarly to (4) above, you are using a DataOutputStream around a BufferedOutputStream for some things and the socket output stream directly for others. Don't do that. All parts of the program must the same output stream or writer for the socket.
You don't need to flush() before close(); it happens automatically.
For some reason after sending the file you are creating a new connection and sending another command. You aren't even closing the connection afterwards. The server will have no easy way of knowing that this connection and this command referred to the file just sent in the code above. It is also redundant, as the receipt of the final EOS tells the server that the file has been sent successfully. Don't do this. If you need to send more information with the file, send it first, before the file, on the same connection.
The reference you cite exhibits many of the above issues. Make an effort to find a reputable starting point.
This is the solution. Please Apply this logic to your code.
I am able to send a file from server to client and client to server.
Check the following code to send the file from Client to Server. It is working great.
If you have any issues let me know.
Server Side Code:
public class ServerRecieveFile {
public static void main(String[] args) throws IOException {// TODO Auto-enerated method stub int filesize=1022386;
int bytesRead; int currentTot= ;
ServerSocket serverSocket=new ServerSocket(15123);
Socket socket=rverSocket.accept();
byte [] bytearray = new byte [filesize];
InputStream is=socket.getInputStream();
File copyFileName=new File("c:/Files Sockets/2.txt");
FileOutputStream fos = new FileOutputStream(copyFileName);
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);
bos.write(bytearray, 0 , currentTot);
bos.flush();
bos.close();
socket.close();
}
}
Client Side code:
public class ClientSendFile {
public static void main(String[] args) throws UnknownHostException, IOException {// TODO Auto-generated method stub
Client client=new Client();
Socket socket = new Socket(InetAddress.getLocalHost(),15123);
System.out.println("Accepted connection : " + socket);
File transferFile = new File ("c:/Files Sockets/1.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();
socket.close();
System.out.println("File transfer complete");
}
}