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Java File transferring with Sockets error ArrayIndexOutOfBoundsException [closed]

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When I run the client, it returns(an error): Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException
at java.lang.System.arraycopy(Native Method)
at java.io.BufferedOutputStream.write(Unknown Source)
at Sockets.FileSocketClient.main(FileSocketClient.java:14)
I understand where it is occurring[bos.write(mybytearray, 0, bytesRead);], I just don't understand WHY
Server
import java.io.*;
import java.net.*;
public class FileSocketServer {
public static void main(String args[]) throws IOException {
ServerSocket serverSocket = new ServerSocket(1235);
File myFile = new File("test.txt");
while(true) {
Socket socket = serverSocket.accept(); //Understand
byte[] mybytearray = new byte[(int)myFile.length()]; //Don't understand
BufferedInputStream bis = new BufferedInputStream(new FileInputStream(myFile)); //Don't understand
bis.read(mybytearray, 0, mybytearray.length); //Don't understand
OutputStream os = socket.getOutputStream(); //Don't understand
os.write(mybytearray, 0, mybytearray.length); //Don't understand
os.flush(); //Don't understand
socket.close(); //Don't understand
}
}
}
Client
package Sockets;
import java.io.*;
import java.net.*;
public class FileSocketClient {
public static void main(String args[]) throws IOException{
Socket socket = new Socket("GANNON-PC", 1235); //Understand
byte[] mybytearray = new byte[1024]; //Don't understand
InputStream is = socket.getInputStream(); //Don't understand
FileOutputStream fos = new FileOutputStream("mods//test.txt"); //Don't understand
BufferedOutputStream bos = new BufferedOutputStream(fos); //Don't understand
int bytesRead = is.read(mybytearray, 0, mybytearray.length); //Don't understand
bos.write(mybytearray, 0, bytesRead); //Don't understand
bos.close(); //
socket.close();
}
}

The proper way to send a file:
public void sendFile(Socket socket, File myFile) throws IOException {
DataOutputStream dos = new DataOutputStream(socket.getOutputStream()); //get the output stream of the socket
dos.writeInt((int) myFile.length()); //write in the length of the file
InputStream in = new FileInputStream(myFile); //create an inputstream from the file
OutputStream out = socket.getOutputStream(); //get output stream
byte[] buf = new byte[8192]; //create buffer
int len = 0;
while ((len = in.read(buf)) != -1) {
out.write(buf, 0, len); //write buffer
}
in.close(); //clean up
out.close();
}
Receive a file:
public void receiveFile(Socket socket, String fileName) throws IOException {
DataInputStream dis = new DataInputStream(socket.getInputStream()); //get the socket's input stream
int size = dis.readInt(); //get the size of the file.
InputStream in = socket.getInputStream();
OutputStream out = new FileOutputStream(fileName); //stream to write out file
int totalBytesRead = 0;
byte[] buf = new byte[8192]; //buffer
int len = 0;
while ((len = in.read(buf)) != -1) {
out.write(buf, 0, len); //write buffer
}
out.close(); //clean up
in.close();
}
The difference between this code and yours is first I send over the length of the file before I send the entire file. The file might be bigger than the buffer you have allocated for it, so you need a loop to read it incrementally.

Transfer Java Object through Sockets, Byte[]

Would you take a look over this?:
This is my client:
try {
Socket socket = new Socket("127.0.0.1", 3000);
OutputStream out = socket.getOutputStream();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(baos);
oos.writeObject(mp3data);
oos.close();
byte[] bytes = baos.toByteArray();
out.write(bytes);
}
catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
This is my server:
int port = 3000;
try {
ServerSocket clientConnect = new ServerSocket(port);
System.out.println("SimpleServer running on port" + port);
Socket clientSock = clientConnect.accept();
InputStream is = clientSock.getInputStream();
byte[] buffer = new byte[1024];
int read = is.read(buffer);
ObjectInputStream ois = new ObjectInputStream(is);
MP3[] songs = (MP3[])ois.readObject();
clientSock.close();
// HTML erzeugen
Website site = new Website("index2.html",songs);
} catch (Exception e) {
System.out.println (e);
}
It ain't work. I don't get any exceptions but the Website-Constructor isn't called.

You assume that the whole byte array is read in just one call to read(), and has a length of exactly 1024 bytes. That's not the case (unless you're extremely lucky). Moreover, your ObjectInputStream is wrapping the InputStream from which you have already read the bytes (or some of the bytes) constituting the message. And also, the bytes written by the sender are not flushed.
Don't ignore the result of the call to is.read(): It tells you how many bytes have actually been read. And until it's not -1, you should continue to read, in a loop.
Read the Java tutorial on byte streams.
That said, you're making things difficult. Why don't you write the object directly to the socket output stream, and read the object directly from the socket input stream at the other side?

int port = 3000;
try {
ServerSocket clientConnect = new ServerSocket(port);
System.out.println("SimpleServer running on port" + port);
Socket clientSock = clientConnect.accept();
InputStream is = clientSock.getInputStream();
byte[] buffer = new byte[1024];
for (int i = 0; i < buffer.length; i++) {
int b = is.read();
if (b ==-1) break;
buffer[i] = (byte) b;
}
ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(buffer));
MP3[] songs = (MP3[])ois.readObject();;
ois.close();
clientSock.close();

Able to send images over socket but not text files

My client can send Images normally to server, but when it comes to text files they arrive empty. Any ideas what am I doing wrong? I'd really appreciate help, because I have been trying to make this work for many days now. Thanks.
Here is the server code:
class TheServer {
public void setUp() throws IOException { // this method is called from Main class.
ServerSocket serverSocket = new ServerSocket(1991);
System.out.println("Server setup and listening...");
Socket connection = serverSocket.accept();
System.out.println("Client connect");
System.out.println("Socket is closed = " + serverSocket.isClosed());
BufferedReader rd = new BufferedReader(new InputStreamReader(connection.getInputStream()));
String str = rd.readLine();
System.out.println("Recieved: " + str);
rd.close();
InputStream is = connection.getInputStream();
int bufferSize = connection.getReceiveBufferSize();
FileOutputStream fos = new FileOutputStream("C:/" + str);
BufferedOutputStream bos = new BufferedOutputStream(fos);
byte[] bytes = new byte[bufferSize];
int count;
while ((count = is.read(bytes)) > 0) {
bos.write(bytes, 0, count);
}
bos.flush();
bos.close();
is.close();
connection.close();
serverSocket.close();
}
}
and here is the client code:
public class TheClient {
public void send(File file) throws UnknownHostException, IOException { // this method is called from Main class.
Socket socket = null;
String host = "127.0.0.1";
socket = new Socket(host, 1991);
// Get the size of the file
long length = file.length();
if (length > Integer.MAX_VALUE) {
System.out.println("File is too large.");
}
BufferedWriter wr = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
wr.write(file.getName());
wr.newLine();
wr.flush();
byte[] bytes = new byte[(int) length];
FileInputStream fis = new FileInputStream(file);
BufferedInputStream bis = new BufferedInputStream(fis);
BufferedOutputStream out = new BufferedOutputStream(socket.getOutputStream());
int count;
while ((count = bis.read(bytes)) > 0) {
out.write(bytes, 0, count);
}
out.flush();
out.close();
fis.close();
bis.close();
socket.close();
}
}

You are prematurely closing BufferedReader on server side before reading all the data. This essentially closes the connection.
You should not use Reader or Writer for non-character streams like binary image data. And you should not mix BufferedReader with any other stream wrapper for the same stream since it may read as many data as it fills in buffer.

Java sending and receiving file (byte[]) over sockets

I am trying to develop a very simple client / server where the client converts a file to bytes, sends it to the server, and then converts the bytes back in to a file.
Currently the program just creates an empty file. I'm not a fantastic Java developer so any help much appreciated.
This is the server part that receives what the client sends.
ServerSocket serverSocket = null;
serverSocket = new ServerSocket(4444);
Socket socket = null;
socket = serverSocket.accept();
DataOutputStream out = new DataOutputStream(new BufferedOutputStream(socket.getOutputStream()));
DataInputStream in = new DataInputStream(new BufferedInputStream(socket.getInputStream()));
byte[] bytes = new byte[1024];
in.read(bytes);
System.out.println(bytes);
FileOutputStream fos = new FileOutputStream("C:\\test2.xml");
fos.write(bytes);
And here is the client part
Socket socket = null;
DataOutputStream out = null;
DataInputStream in = null;
String host = "127.0.0.1";
socket = new Socket(host, 4444);
out = new DataOutputStream(new BufferedOutputStream(socket.getOutputStream()));
in = new DataInputStream(new BufferedInputStream(socket.getInputStream()));
File file = new File("C:\\test.xml");
//InputStream is = new FileInputStream(file);
// Get the size of the file
long length = file.length();
if (length > Integer.MAX_VALUE) {
System.out.println("File is too large.");
}
byte[] bytes = new byte[(int) length];
//out.write(bytes);
System.out.println(bytes);
out.close();
in.close();
socket.close();

The correct way to copy a stream in Java is as follows:
int count;
byte[] buffer = new byte[8192]; // or 4096, or more
while ((count = in.read(buffer)) > 0)
{
out.write(buffer, 0, count);
}
Wish I had a dollar for every time I've posted that in a forum.

Thanks for the help. I've managed to get it working now so thought I would post so that the others can use to help them.
Server:
public class Server {
public static void main(String[] args) throws IOException {
ServerSocket serverSocket = null;
try {
serverSocket = new ServerSocket(4444);
} catch (IOException ex) {
System.out.println("Can't setup server on this port number. ");
}
Socket socket = null;
InputStream in = null;
OutputStream out = null;
try {
socket = serverSocket.accept();
} catch (IOException ex) {
System.out.println("Can't accept client connection. ");
}
try {
in = socket.getInputStream();
} catch (IOException ex) {
System.out.println("Can't get socket input stream. ");
}
try {
out = new FileOutputStream("M:\\test2.xml");
} catch (FileNotFoundException ex) {
System.out.println("File not found. ");
}
byte[] bytes = new byte[16*1024];
int count;
while ((count = in.read(bytes)) > 0) {
out.write(bytes, 0, count);
}
out.close();
in.close();
socket.close();
serverSocket.close();
}
}
and the Client:
public class Client {
public static void main(String[] args) throws IOException {
Socket socket = null;
String host = "127.0.0.1";
socket = new Socket(host, 4444);
File file = new File("M:\\test.xml");
// Get the size of the file
long length = file.length();
byte[] bytes = new byte[16 * 1024];
InputStream in = new FileInputStream(file);
OutputStream out = socket.getOutputStream();
int count;
while ((count = in.read(bytes)) > 0) {
out.write(bytes, 0, count);
}
out.close();
in.close();
socket.close();
}
}

Here is the server
Open a stream to the file and send it overnetwork
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
public class SimpleFileServer {
public final static int SOCKET_PORT = 5501;
public final static String FILE_TO_SEND = "file.txt";
public static void main (String [] args ) throws IOException {
FileInputStream fis = null;
BufferedInputStream bis = null;
OutputStream os = null;
ServerSocket servsock = null;
Socket sock = null;
try {
servsock = new ServerSocket(SOCKET_PORT);
while (true) {
System.out.println("Waiting...");
try {
sock = servsock.accept();
System.out.println("Accepted connection : " + sock);
// send file
File myFile = new File (FILE_TO_SEND);
byte [] mybytearray = new byte [(int)myFile.length()];
fis = new FileInputStream(myFile);
bis = new BufferedInputStream(fis);
bis.read(mybytearray,0,mybytearray.length);
os = sock.getOutputStream();
System.out.println("Sending " + FILE_TO_SEND + "(" + mybytearray.length + " bytes)");
os.write(mybytearray,0,mybytearray.length);
os.flush();
System.out.println("Done.");
} catch (IOException ex) {
System.out.println(ex.getMessage()+": An Inbound Connection Was Not Resolved");
}
}finally {
if (bis != null) bis.close();
if (os != null) os.close();
if (sock!=null) sock.close();
}
}
}
finally {
if (servsock != null)
servsock.close();
}
}
}
Here is the client
Recive the file being sent overnetwork
import java.io.BufferedOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.Socket;
public class SimpleFileClient {
public final static int SOCKET_PORT = 5501;
public final static String SERVER = "127.0.0.1";
public final static String
FILE_TO_RECEIVED = "file-rec.txt";
public final static int FILE_SIZE = Integer.MAX_VALUE;
public static void main (String [] args ) throws IOException {
int bytesRead;
int current = 0;
FileOutputStream fos = null;
BufferedOutputStream bos = null;
Socket sock = null;
try {
sock = new Socket(SERVER, SOCKET_PORT);
System.out.println("Connecting...");
// receive file
byte [] mybytearray = new byte [FILE_SIZE];
InputStream is = sock.getInputStream();
fos = new FileOutputStream(FILE_TO_RECEIVED);
bos = new BufferedOutputStream(fos);
bytesRead = is.read(mybytearray,0,mybytearray.length);
current = bytesRead;
do {
bytesRead =
is.read(mybytearray, current, (mybytearray.length-current));
if(bytesRead >= 0) current += bytesRead;
} while(bytesRead > -1);
bos.write(mybytearray, 0 , current);
bos.flush();
System.out.println("File " + FILE_TO_RECEIVED
+ " downloaded (" + current + " bytes read)");
}
finally {
if (fos != null) fos.close();
if (bos != null) bos.close();
if (sock != null) sock.close();
}
}
}

To avoid the limitation of the file size , which can cause the Exception java.lang.OutOfMemoryError to be thrown when creating an array of the file size byte[] bytes = new byte[(int) length];, instead we could do
byte[] bytearray = new byte[1024*16];
FileInputStream fis = null;
try {
fis = new FileInputStream(file);
OutputStream output= socket.getOututStream();
BufferedInputStream bis = new BufferedInputStream(fis);
int readLength = -1;
while ((readLength = bis.read(bytearray)) > 0) {
output.write(bytearray, 0, readLength);
}
bis.close();
output.close();
}
catch(Exception ex ){
ex.printStackTrace();
} //Excuse the poor exception handling...

Rookie, if you want to write a file to server by socket, how about using fileoutputstream instead of dataoutputstream? dataoutputstream is more fit for protocol-level read-write. it is not very reasonable for your code in bytes reading and writing. loop to read and write is necessary in java io. and also, you use a buffer way. flush is necessary. here is a code sample: http://www.rgagnon.com/javadetails/java-0542.html

Adding up on EJP's answer; use this for more fluidity.
Make sure you don't put his code inside a bigger try catch with more code between the .read and the catch block, it may return an exception and jump all the way to the outer catch block, safest bet is to place EJPS's while loop inside a try catch, and then continue the code after it, like:
int count;
byte[] bytes = new byte[4096];
try {
while ((count = is.read(bytes)) > 0) {
System.out.println(count);
bos.write(bytes, 0, count);
}
} catch ( Exception e )
{
//It will land here....
}
// Then continue from here
EDIT: ^This happened to me cuz I didn't realize you need to put socket.shutDownOutput() if it's a client-to-server stream!
Hope this post solves any of your issues

why does ByteArrayInputStream doesn't return expected results?

I am trying to interact with an application in windows server through telnet, so I am using TelnetClient() method. I could interact (send commands and retrieve results) using System.in.read(), however I want this program to run automatically without using any keyboard inputs. So, my question is, why does System.in.read() works, yet ByteArrayInputStream doesn't?
This is my code so far :
public class telnetExample2 implements Runnable, TelnetNotificationHandler{
static TelnetClient tc = null;
public static void main (String args[]) throws IOException, InterruptedException{
tc = new TelnetClient();
while (true){
try{
tc.connect("192.168.1.13", 8999);
}
catch (SocketException ex){
Logger.getLogger(telnetExample2.class.getName()).log(Level.SEVERE, null,ex);
}
Thread reader = new Thread(new telnetExample2());
tc.registerNotifHandler(new telnetExample2());
String command = "getversion"; //this is the command i would like to write
OutputStream os = tc.getOutputStream();
InputStream is = new ByteArrayInputStream(command.getBytes("UTF-8")); //i'm using UTF-8 charset encoding here
byte[] buff = new byte[1024];
int ret_read = 0;
do{
ret_read = is.read(buff);
os.write(buff, 0, 10)
os.flush();
while(ret_read>=0);
}
}
public void run(){
InputStream instr = tc.getInputStream();
try{
byte[] buff = new byte[1024];
int ret_read = 0;
do{
ret_read = instr.read(buff);
if(ret_read >0){
System.out.print(new String(nuff, 0, ret_read));
}
while(ret_read>=0);}
catch(Exception e){
System.err.println("Exception while reading socket:" + e.getMessage());
}
}
public void receiveNegotiation(int i, int ii){
throw new UnsupportedOperationException("Not supported");
}
}

InputStream is = new ByteArrayInputStream(command.getBytes("UTF-8")); //i'm using UTF-8 charset encoding here
byte[] buff = new byte[1024];
int ret_read = 0;
do{
ret_read = is.read(buff);
os.write(buff, 0, 10)
os.flush();
while(ret_read>=0);
}
You can reduce those 9 lines that don't work to os.write(command.getBytes("UTF-8")); which does.
Why you thought that reading up to 1024 bytes into a buffer and then writing out only the first ten of them was ever going to work is a mystery.