Develop Reference

Reading JPEG Stream over socket gives Null characters

I am reading a .jpg file over InputStream using this code but I am receiving NULNUL...n stream after some text. Ii am reading this file link to file and link of file that I received , link is Written File link.
while ((ret = input.read(imageCharArray)) != -1) {
packet.append(new String(imageCharArray, 0, ret));
totRead += ret;
imageCharArray = new char[4096];
}
file = new File(
Environment.getExternalStorageDirectory()
+ "/FileName_/"
+ m_httpParser.filename + ".jpg");
PrintWriter printWriter = new PrintWriter(file);
// outputStream = new FileOutputStream(file); //also Used FileoutputStream for writting
// outputStream.write(packet.toString().getBytes());//
// ,
printWriter.write(packet.toString());
// outputStream.close();
printWriter.close();
}
I have also tried FileoutputStream but hardlucj for this too as commented in my code.
Edit
I have used this also. I have a content length field upto which i am reading and writing
byte[] bytes = new byte[1024];
int totalReadLength = 0;
// read untill we have bytes
while ((read = inputStream.read(bytes)) != -1
&& contentLength >= (totalReadLength)) {
outputStream.write(bytes, 0, read);
totalReadLength += read;
System.out.println(" read size ======= "
+ read + " totalReadLength = "
+ totalReadLength);
}

String is not a container for binary data, and PrintWriter isn't a way to write it. Get rid of all, all, the conversions between bytes and String and vice versa, and just transfer the bytes with input and output streams:
while ((count = in.read(buffer)) > 0)
{
out.write(buffer, 0, count);
}
If you need to constrain the number of bytes read from the input, you have to do that before calling read(), and you also have to constrain the read() correctly:
while (total < length && (count = in.read(buffer, 0, length-total > buffer.length ? buffer.length: (int)(length-total))) > 0)
{
total += count;
out.write(buffer, 0, count);
}

I tested it in my Nexus4 and it's working for me. Here is the snippet of code what I tried :
public void saveImage(String urlPath)throws Exception{
String fileName = "kumar.jpg";
File folder = new File("/sdcard/MyImages/");
// have the object build the directory structure, if needed.
folder.mkdirs();
final File output = new File(folder,
fileName);
if (output.exists()) {
output.delete();
}
InputStream stream = null;
FileOutputStream fos = null;
try {
URL url = new URL(urlPath);
stream = url.openConnection().getInputStream();
// InputStreamReader reader = new InputStreamReader(stream);
DataInputStream dis = new DataInputStream(url.openConnection().getInputStream());
byte[] fileData = new byte[url.openConnection().getContentLength()];
for (int x = 0; x < fileData.length; x++) { // fill byte array with bytes from the data input stream
fileData[x] = dis.readByte();
}
dis.close();
fos = new FileOutputStream(output.getPath());
fos.write(fileData);
} catch (Exception e) {
e.printStackTrace();
} finally {
if (stream != null) {
try {
stream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (fos != null) {
try {
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
Just Call the above function in a background thread and pass your url. It'll work for sure. Let me know if it helps.

You can check below code.
destinationFile = new File(
Environment.getExternalStorageDirectory()
+ "/FileName_/"
+ m_httpParser.filename + ".jpg");
BufferedOutputStream buffer = new BufferedOutputStream(new FileOutputStream(destinationFile));
byte byt[] = new byte[1024];
int i;
for (long l = 0L; (i = input.read(byt)) != -1; l += i ) {
buffer.write(byt, 0, i);
}
buffer.close();

PDF to Bytearray conversion in java

Below is my code to convert a PDF file to byte array
public class ByteArrayExample{
public static void main(String[] args) {
try{
BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter File name: ");
String str = bf.readLine();
File file = new File(str);
//File length
int size = (int)file.length();
if (size > Integer.MAX_VALUE){
System.out.println("File is to larger");
}
byte[] bytes = new byte[size];
DataInputStream dis = new DataInputStream(new FileInputStream(file));
int read = 0;
int numRead = 0;
while (read < bytes.length && (numRead=dis.read(bytes, read,
bytes.length-read)) >= 0) {
read = read + numRead;
}
System.out.println("File size: " + read);
// Ensure all the bytes have been read in
if (read < bytes.length) {
System.out.println("Could not completely read: "+file.getName());
}
}
catch (Exception e){
e.getMessage();
}
}
}
Issue is this actually converts the file name into the byte array not the actual PDF file.Can anyone please help me with this.

I added this to the end to check it and it copied the PDF file. Your code is working fine
dis.close();
DataOutputStream out = new DataOutputStream(new FileOutputStream(new File("c:\\out.pdf")));
out.write(bytes);
out.close();
System.out.println("File size: " + read);
// Ensure all the bytes have been read in
if (read < bytes.length) {
System.out.println("Could not completely read: "+file.getName());
}
edit: here is my entire code, its just copied from yours. I ran it in IDE (eclipse) and entered "c:\mypdf.pdf" for the input and it copied it to out.pdf. Identical Copys. Do note that I did close both streams which I noticed you forgot to do in your code.
public class Main {
public static void main(String[] args) {
try {
BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter File name: ");
String str = bf.readLine();
File file = new File(str);
//File length
int size = (int) file.length();
if (size > Integer.MAX_VALUE) {
System.out.println("File is to larger");
}
byte[] bytes = new byte[size];
DataInputStream dis = new DataInputStream(new FileInputStream(file));
int read = 0;
int numRead = 0;
while (read < bytes.length && (numRead = dis.read(bytes, read,
bytes.length - read)) >= 0) {
read = read + numRead;
}
dis.close();
DataOutputStream out = new DataOutputStream(new FileOutputStream(new File("c:\\out.pdf")));
out.write(bytes);
out.close();
System.out.println("File size: " + read);
// Ensure all the bytes have been read in
if (read < bytes.length) {
System.out.println("Could not completely read: " + file.getName());
}
} catch (Exception e) {
e.getMessage();
}
}
}

Message returned is null

Hi i have a problem with my server, everytime i call "dload" the file gets downloaded but i can't use the other commands i have because they get returned as null. Anyone who can see the problem in the code?
Server :
public class TCPServer {
public static void main(String[] args) {
ServerSocket server = null;
Socket client;
// Default port number we are going to use
int portnumber = 1234;
if (args.length >= 1) {
portnumber = Integer.parseInt(args[0]);
}
// Create Server side socket
try {
server = new ServerSocket(portnumber);
} catch (IOException ie) {
System.out.println("Cannot open socket." + ie);
System.exit(1);
}
System.out.println("ServerSocket is created " + server);
// Wait for the data from the client and reply
boolean isConnected = true;
try {
// Listens for a connection to be made to
// this socket and accepts it. The method blocks until
// a connection is made
System.out.println("Waiting for connect request...");
client = server.accept();
System.out.println("Connect request is accepted...");
String clientHost = client.getInetAddress().getHostAddress();
int clientPort = client.getPort();
System.out.println("Client host = " + clientHost
+ " Client port = " + clientPort);
// Read data from the client
while (isConnected == true) {
InputStream clientIn = client.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(
clientIn));
String msgFromClient = br.readLine();
System.out.println("Message received from client = "
+ msgFromClient);
// Send response to the client
if (msgFromClient != null
&& msgFromClient.equalsIgnoreCase("sum")) {
OutputStream clientOut = client.getOutputStream();
PrintWriter pw = new PrintWriter(clientOut, true);
Double[] list;
list = new Double[5];
String value;
int i;
try {
for (i = 0; i < 5; i++) {
pw.println("Input number in arrayslot: " + i);
value = br.readLine();
double DoubleValue = Double.parseDouble(value);
list[i] = DoubleValue;
}
if (i == 5) {
Double sum = 0.0;
for (int k = 0; k < 5; k++) {
sum = sum + list[k];
}
pw.println("Sum of array is " + sum);
}
} catch (NumberFormatException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (msgFromClient != null
&& msgFromClient.equalsIgnoreCase("max")) {
OutputStream clientOut = client.getOutputStream();
PrintWriter pw = new PrintWriter(clientOut, true);
Double[] list;
list = new Double[5];
String value;
int i;
try {
for (i = 0; i < 5; i++) {
pw.println("Input number in arrayslot: " + i);
value = br.readLine();
double DoubleValue = Double.parseDouble(value);
list[i] = DoubleValue;
}
if (i == 5) {
Arrays.sort(list);
pw.println("Max integer in array is " + list[4]);
}
} catch (NumberFormatException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (msgFromClient != null
&& msgFromClient.equalsIgnoreCase("time")) {
OutputStream clientOut = client.getOutputStream();
PrintWriter pw = new PrintWriter(clientOut, true);
Calendar calendar = GregorianCalendar.getInstance();
String ansMsg = "Time is:, "
+ calendar.get(Calendar.HOUR_OF_DAY) + ":"
+ calendar.get(Calendar.MINUTE);
pw.println(ansMsg);
}
if (msgFromClient != null
&& msgFromClient.equalsIgnoreCase("date")) {
OutputStream clientOut = client.getOutputStream();
PrintWriter pw = new PrintWriter(clientOut, true);
Calendar calendar = GregorianCalendar.getInstance();
String ansMsg = "Date is: " + calendar.get(Calendar.DATE)
+ "/" + calendar.get(Calendar.MONTH) + "/"
+ calendar.get(Calendar.YEAR);
;
pw.println(ansMsg);
}
if (msgFromClient != null
&& msgFromClient.equalsIgnoreCase("c2f")) {
OutputStream clientOut = client.getOutputStream();
PrintWriter pw = new PrintWriter(clientOut, true);
String celciusValue;
boolean ifRead = false;
try {
pw.println("Input celcius value");
celciusValue = br.readLine();
ifRead = true;
if (ifRead == true) {
double celcius = Double.parseDouble(celciusValue);
celcius = celcius * 9 / 5 + 32;
pw.println(celcius);
}
} catch (NumberFormatException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (msgFromClient != null
&& msgFromClient.equalsIgnoreCase("dload")) {
OutputStream outToClient = client.getOutputStream();
if (outToClient != null) {
File myFile = new File("C:\\ftp\\pic.png");
byte[] mybytearray = new byte[(int) myFile.length()];
FileInputStream fis = new FileInputStream(myFile);
BufferedInputStream bis = new BufferedInputStream(fis);
try {
bis.read(mybytearray, 0, mybytearray.length);
outToClient.write(mybytearray, 0,
mybytearray.length);
outToClient.flush();
outToClient.close();
bis.close();
fis.close();
} catch (IOException ex) {
// Do exception handling
}
System.out.println("test");
}
}
if (msgFromClient != null
&& msgFromClient.equalsIgnoreCase("quit")) {
client.close();
break;
}
// if (msgFromClient != null
// && !msgFromClient.equalsIgnoreCase("bye")) {
// OutputStream clientOut = client.getOutputStream();
// PrintWriter pw = new PrintWriter(clientOut, true);
// String ansMsg = "Hello, " + msgFromClient;
// pw.println(ansMsg);
// }
// Close sockets
if (msgFromClient != null
&& msgFromClient.equalsIgnoreCase("bye")) {
server.close();
client.close();
break;
}
msgFromClient = null;
}
} catch (IOException ie) {
}
}
}
Client:
import java.io.*;
import java.net.*;
public class TCPClient {
public static void main(String args[]) {
boolean isConnected = true;
Socket client = null;
int portnumber = 1234; // Default port number we are going to use
if (args.length >= 1) {
portnumber = Integer.parseInt(args[0]);
}
try {
String msg = "";
// Create a client socket
client = new Socket("127.0.0.1", 1234);
System.out.println("Client socket is created " + client);
// Create an output stream of the client socket
OutputStream clientOut = client.getOutputStream();
PrintWriter pw = new PrintWriter(clientOut, true);
// Create an input stream of the client socket
InputStream clientIn = client.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(
clientIn));
// Create BufferedReader for a standard input
BufferedReader stdIn = new BufferedReader(new InputStreamReader(
System.in));
while (isConnected == true) {
System.out
.println("Commands: \n1. TIME\n2. DATE\n3. C2F\n4. MAX\n5. SUM\n6. DLOAD\n7. QUIT");
// Read data from standard input device and write it
// to the output stream of the client socket.
msg = stdIn.readLine().trim();
pw.println(msg);
// Read data from the input stream of the client socket.
if (msg.equalsIgnoreCase("dload")) {
byte[] aByte = new byte[1];
int bytesRead;
ByteArrayOutputStream baos = new ByteArrayOutputStream();
if (clientIn != null) {
try {
FileOutputStream fos = new FileOutputStream("C:\\ftp\\pic.png");
BufferedOutputStream bos = new BufferedOutputStream(fos);
bytesRead = clientIn.read(aByte, 0, aByte.length);
do {
baos.write(aByte, 0, bytesRead);
bytesRead = clientIn.read(aByte);
} while (bytesRead != -1);
bos.write(baos.toByteArray());
bos.flush();
bos.close();
System.out.println("File is successfully downloaded to your selected directory"+ "\n" +"*-----------------*"+ "\n" );
} catch (IOException ex) {
System.out.println("Couldn't dowload the selected file, ERROR CODE "+ex);
}
}
}else{
System.out.println("Message returned from the server = "
+ br.readLine());
}
if (msg.equalsIgnoreCase("bye")) {
pw.close();
br.close();
break;
}
}
} catch (Exception e) {
}
}
}

debugged your code and have two hints:
1)
don't surpress your exceptions. handle them! first step would to print your stacktrace and this question on SO wouldn't ever be opened ;-) debug your code!
2)
outToClient.flush();
outToClient.close(); //is closing the socket implicitly
bis.close();
fis.close();
so in your second call the socket on server-side will already be closed.

first thing:
if (args.length >= 1) {
portnumber = Integer.parseInt(args[0]);
}
This can throw a NumberFormatException, and because args[0] is passed by the user you should handle this.
reading the code also this gave me a problem:
double DoubleValue = Double.parseDouble(value); // LINE 104
Throwing a NumberFormatException when I give c2f as command to the server. You definitively need to handle this exception anywhere in your code and give proper answer to the client, something like:
try{
double DoubleValue = Double.parseDouble(value);
}catch(NumberFormatException e){
// TELL THE CLIENT "ops, the number you inserted is not a valid double numer
}
(in short example, starting from this you have to enlarge the code)
while (isConnected == true) {
I cannot see it! why not use this?
while (isConnected) {
if (msgFromClient != null && msgFromClient.equalsIgnoreCase("sum")){
can be:
if("sum".equalsIgnoreCase(msgFromClient)){
in this case you have no problem with the NullPointerException. (if msgFromClient is null the statement is false).
By the way, date and time command are working fine for me. Check the others.
To fix dload i think you have to delete the line:
outToClient.close();
(EDIT: sorry to maxhax for the same answr, didn't see your answer while writing this)

How to trap ftp success/failure in sun.net.ftp.FtpClient?

I want to know if really 'put' has succeeded in putting the file to destination. If for any reason the file is not put in destination [maybe due to problems in destination server like space constraint, etc] I need to know that.
Code:
private static boolean putFile(String m_sLocalFile, FtpClient m_client) {
boolean success = false;
int BUFFER_SIZE = 10240;
if (m_sLocalFile.length() == 0) {
System.out.println("Please enter file name");
}
byte[] buffer = new byte[BUFFER_SIZE];
try {
File f = new File(m_sLocalFile);
int size = (int) f.length();
System.out.println("File " + m_sLocalFile + ": " + size + " bytes");
System.out.println(size);
FileInputStream in = new FileInputStream(m_sLocalFile);
OutputStream out = m_client.put(f.getName());
int counter = 0;
while (true) {
int bytes = in.read(buffer);
if (bytes < 0)
break;
out.write(buffer, 0, bytes);
counter += bytes;
System.out.println(counter);
}
out.close();
in.close();
} catch (Exception ex) {
System.out.println("Error: " + ex.toString());
}
return success;
}

I would expect it to throw an IOException. Do you have any reason to believe it doesn't? But you shouldn't be using that class directly, you should be using an ftp: URL and its URLConnection class to do the I/O with, after calling setDoOutput(true).

problem with server and client , working on my machine not working on another

hello guys i have designed a server client which transfers data through sockets. Everything is ok when i run it on my machine it works 100% of the time. When i run the server on another machine and the client on mine, i am unable to get data. when i run the server on my machine and the client on theirs i am unable to put data , but i can get. i dont know what is going on, maybe you can shed some light.
There is more code that makes this work correctly but i omit that out to reduce the complications . Please if you get a chanse look at this and tell me why it works on my system but not on the server? and does anyone know how to debug this? i mean this is run on the server how can i debug a server since i cannot be there (and everything works correctly on my system?)
Server :
if (get.equals("get")) {
try {
Copy copy = new Copy(socket, dir);//maybe dir is not needed
String name = input.substring(4);
File checkFile = new File(dir.getCurrentPath(), name);
DataOutputStream outToClient = new DataOutputStream(socket.getOutputStream());
if (checkFile.isFile() && checkFile.exists()) {
outToClient.writeBytes("continue" + "\n");
BufferedReader inFromServer = new BufferedReader(new InputStreamReader(
socket.getInputStream()));
boolean cont = false;
String x;
while (!cont) {
if ((x = inFromServer.readLine()).equals("continue")) {
cont = true;
}
}
copy.copyFile(name);
output = "File copied to client successfully" + "\n";
} else {
outToClient.writeBytes("File failed to be copied to client" + "\n");
output = "";
}
} catch (Exception e) {
output = "Failed to Copy File to client" + "\n";
}
} else if (get.equals("put")) {
//so the client sends: the put request
//then sends the length
try {
DataInputStream inFromClient = new DataInputStream(socket.getInputStream());
DataOutputStream outToClient = new DataOutputStream(socket.getOutputStream());
outToClient.writeBytes("continue" + "\n");
long lengthLong = (inFromClient.readLong());
int length = (int) lengthLong;
byte[] recieveFile = new byte[length];//FIX THE LENGTH
// InputStream is = socket.getInputStream();
FileOutputStream fos = new FileOutputStream("Copy " + input.substring(4));
BufferedOutputStream bos = new BufferedOutputStream(fos);
int bytesRead;
int current = 0;
bytesRead = inFromClient.read(recieveFile, 0, recieveFile.length);
current = bytesRead;
do {
bytesRead = inFromClient.read(recieveFile, current, (recieveFile.length - current));
if (bytesRead >= 0)
current += bytesRead;
} while (bytesRead > 0); // FIX THE LENGTH
bos.write(recieveFile, 0, current);
bos.flush();
bos.close();
output = "File copied to Server successfully" + " \n";
The copy class:
File checkFile = new File(dir.getCurrentPath(), file);
if (checkFile.isFile() && checkFile.exists()) {
DataOutputStream outToClient = new DataOutputStream(socket.getOutputStream());
// byte[] receivedData = new byte[8192];
File inputFile = new File(dir.getCurrentPath(), file);
byte[] receivedData = new byte[(int) inputFile.length()];
long length = inputFile.length();
outToClient.writeLong(length);
//maybe wait here for get request?
DataInputStream dis = new DataInputStream(new FileInputStream(getCopyPath(file)));
dis.read(receivedData, 0, receivedData.length);
OutputStream os = socket.getOutputStream();
outToClient.write(receivedData, 0, receivedData.length);//outputStreasm replaced by Datatoutputstream
outToClient.flush();
The client class:
else if (sentence.length() > 3 && sentence.substring(0, 3).equals("get")) {
outToServer.writeBytes(sentence + "\n");
String response = inFromServer.readLine();
if (response.equals("File failed to be copied to client")) {
System.out.println(response);
} else {
DataInputStream inFromClient = new DataInputStream(clientSocket.getInputStream());
DataOutputStream outToClient = new DataOutputStream(clientSocket.getOutputStream());
outToClient.writeBytes("continue" + "\n");
long lengthLong = (inFromClient.readLong());
int length = (int) lengthLong;
byte[] recieveFile = new byte[length];
FileOutputStream fos = new FileOutputStream("Copy " + sentence.substring(4));
BufferedOutputStream bos = new BufferedOutputStream(fos);
int bytesRead;
int current = 0;
bytesRead = inFromClient.read(recieveFile, 0, recieveFile.length);
current = bytesRead;
do {
bytesRead = inFromClient.read(recieveFile, current, (recieveFile.length - current));
if (bytesRead >= 0)
current += bytesRead;
} while (bytesRead > 0);
bos.write(recieveFile, 0, current);
bos.flush();
bos.close();
}
} else if (sentence.length() > 3 && sentence.substring(0, 3).equals("put")) {
File checkFile = new File(dir.getCurrentPath(), sentence.substring(4));
if (checkFile.isFile() && checkFile.exists()) {
try {
outToServer.writeBytes(sentence + "\n");
boolean cont = false;
String x;
while (!cont) {
if ((x = inFromServer.readLine()).equals("continue")) {
cont = true;
}
}
String name = sentence.substring(4);
copy.copyFile(name);