After creating socket connection in Android App, i can't write in buffer after reading.
This is an example for establishing connection with my Server:
//...
try{
socket = new Socket(IP, Port);
out = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())), true);
in =new BufferedReader(new InputStreamReader(socket.getInputStream()));
//ask for connection
out.println(req1);
//server send me a nonce
result=in.readLine().toString();
//encrypting nonce with specific alghorithm
passwd=Password.get_Passwd(result);
//sending password
out.println(passwd); //here out.println doesn't write
//...
} catch (IOException e){
e.printStackTrace();
} finally {
try {
socket.close();
out.close();
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
//...
So can any one help me solving this problem. Thanks.
Related
So i'm trying to send multiple lines of code everytime i type something in the client console. However when doing this it only prints the output of the client in the server once, what i would like to do is print the clients output in the server everytime after entering a line.
Client:
try {
Scanner scanner = new Scanner(System.in);
DataInputStream inputStream = new DataInputStream(socket.getInputStream());
DataOutputStream outputStream;
System.out.println("Write something to client:");
while(scanner.hasNext()) {
System.out.println("Write something to client:");
outputStream = new DataOutputStream(socket.getOutputStream());
String message = scanner.nextLine();
outputStream.writeUTF(message);
}
} catch (IOException e) {
System.out.println("[ERROR] Unable to get streams from server");
}
}
ClientThread:
#Override
public void run() {
try {
DataInputStream inputStream = new DataInputStream(socket.getInputStream());
DataOutputStream outputStream = new DataOutputStream(socket.getOutputStream());
System.out.println(inputStream.readUTF());
} catch (IOException e) {
e.printStackTrace();
}
}
Server:
public Server() {
try {
serverSocket = new ServerSocket(port);
System.out.println("[SERVER] Server initialized successfully");
// consider using!
Runtime.getRuntime().addShutdownHook(new Thread());
} catch (IOException e) {
System.out.println("[ERROR] Unable to launch server on port " + port);
}
while (true) {
Socket socket = null;
try {
socket = serverSocket.accept();
} catch (IOException e) {
System.out.println("[ERROR] Unable to accept client request");
}
System.out.println("[SERVER] New user joined the chat: " + socket);
groupCounter++;
ClientThread client = new ClientThread("Client " + groupCounter, socket);
Thread thread = new Thread(client);
thread.start();
groupClients.add(client);
//System.out.println(groupCounter);
}
The problem is in the server side, serverSocket.accept() stops the execution and waits for a client to connect to the server socket. That's why you only receive one message every time.
Add an infinite loop in the ClientThread to make sure it keeps on reading the client socket input.
try {
while (true) {
DataInputStream inputStream = new DataInputStream(socket.getInputStream());
DataOutputStream outputStream = new DataOutputStream(socket.getOutputStream());
System.out.println(inputStream.readUTF());
}
} catch (IOException e) {
e.printStackTrace();
}
I am opening an SSLSocket on the client side to connect to the server.
But trying to get the socket.getOutputStream() blocks the code, without outputting any errors.
I am flushing both streams, but it still doesn't work.
Server:
SSLSocket socket = (SSLSocket) serverSocket.accept();
socket.setUseClientMode(false);
try{
socket.setSoTimeout(0);
socket.setKeepAlive(true);
socket.addHandshakeCompletedListener(handshakeCompletedEvent -> {
try{
reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
writer = new PrintWriter(new OutputStreamWriter(socket.getOutputStream()));
writer.println("Setup"); writer.flush();
while(running){
if(!socket.isConnected() || socket.isClosed()){
disconnect();
return;
}
for(Iterator<String> pendingIterator = pendingMessages.iterator(); pendingIterator.hasNext();){
String message = pendingIterator.next();
pendingIterator.remove();
writer.println(message); writer.flush();
}
//Auto decrypt when message arrives, but no thread blocking
if(reader.ready()){
String line = reader.readLine();
System.out.println(line);
}
}
}catch(Exception e){
e.printStackTrace();
}
});
socket.startHandshake();
}catch(Exception e){
e.printStackTrace();
disconnect();
}
Client:
socket.addHandshakeCompletedListener(new HandshakeCompletedListener(){
#Override
public void handshakeCompleted(HandshakeCompletedEvent handshakeCompletedEvent){
try{
Log.i("Update", "Did handshake");
writer = new PrintWriter(new OutputStreamWriter(socket.getOutputStream()));
writer.flush();
Log.i("Update", "Writer");
reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
Log.i("Update", "Reader");
while(isRunning){
try{
writer.println("Test");
writer.flush();
Log.i("DATA", "DATA SENT");
}catch(Exception e){
e.printStackTrace();
}
}
writer.close();
reader.close();
socket.close();
}catch(Exception e){
e.printStackTrace();
}
}
});
socket.startHandshake();
You are misusing the handshake completed listener. Its purpose is to let to check he peer certificate, negotiated cipher suite, etc. Not to carry out the transaction. Remove it all and put it inline. You don't need even to call startHandshake(). It will happen automatically on the first I/O.
i want to create a printwriter in my java server and a buffertreader in my android code. right know i can send a message from my android and read it on my java compiler but i want to do the oppsite aswell. read on android and write on server. do i need two applications for that because i dont know if i can just put it in between try i each code?
android code:
try {
client = new Socket("10.0.2.2", 4444); //connect to server
printwriter = new PrintWriter(client.getOutputStream(),true);
printwriter.write(messsage); //write the message to output stream
printwriter.flush();
printwriter.close();
client.close(); //closing the connection
} catch (UnknownHostException e) {
java server:
while (true) {
try {
clientSocket = serverSocket.accept(); //accept the client connection
inputStreamReader = new InputStreamReader(clientSocket.getInputStream());
bufferedReader = new BufferedReader(inputStreamReader); //get the client message
message = bufferedReader.readLine();
System.out.println(message);
inputStreamReader.close();
clientSocket.close();
} catch (IOException ex) {
thank you for taking your time to read my problem
Yes you can create two way communication between them, all you have to do is open an InputStream on the client side (Android) and Open an OutputStream on the Java Server Side, it can be achieved in the following manner:
android code:
try {
client = new Socket("10.0.2.2", 4444); //connect to server
printwriter = new PrintWriter(client.getOutputStream(),true);
printwriter.write(messsage); //write the message to output stream
printwriter.flush();
printwriter.close();
InputStream in = client.getInputStream();
byte data[] = new byte[1024]
in.read(data); ///perform your reading operation here
client.close(); //closing the connection
} catch (UnknownHostException e) {
java server:
while (true) {
try {
clientSocket = serverSocket.accept(); //accept the client connection
inputStreamReader = new InputStreamReader(clientSocket.getInputStream());
bufferedReader = new BufferedReader(inputStreamReader); //get the client message
message = bufferedReader.readLine();
System.out.println(message);
inputStreamReader.close();
PrintWriter pw = new PrintWriter(clientSocket.getOutputStream());
pw.write(new String("write data here"));
pw.flush();
pw.close();
clientSocket.close();
} catch (IOException ex) {
I have two Java applications, where an Android client connects to a server on a computer and sends a message using BufferedWriter over websockets.
The client:
try {
toast("Sending...");
Socket sock = new Socket(ip, PORT);
OutputStream os = sock.getOutputStream();
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(os));
bw.flush();
bw.write("Hello Server!");
toast("Connected!");
} catch (UnknownHostException e) {
toast(e.getMessage());
} catch (IOException e) {
toast(e.getMessage());
}
The server:
public static void main(String[] args) {
ServerSocket server;
ConnectionThread ct;
Socket s;
ExecutorService es = Executors.newSingleThreadExecutor();
try {
System.out.println("Starting server...");
server = new ServerSocket(1337);
s = server.accept();
ct = new ConnectionThread(s);
es.execute(ct);
} catch (IOException ex) {
ex.printStackTrace();
}
}
The ConnectionThread class:
public class ConnectionThread implements Runnable {
private Socket sock;
private InputStream is;
private BufferedReader br;
private boolean online;
public ConnectionThread(Socket s) {
System.out.println("Creating connection thread.");
this.sock = s;
online = true;
}
#Override
public void run() {
String input = "";
try {
System.out.println("Starting to read...");
is = sock.getInputStream();
br = new BufferedReader(new InputStreamReader(is));
while (online) {
input = br.readLine();
if(input != null){
System.out.print("Received message: ");
System.out.println(input);
}
}
br.close();
is.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
When I run the server, and then the client, the client will show the "Connected!" toast, and the server's output will be:
Starting server...
Creating connection thread.
Starting to read...
So, it seems like the connection is actually being made, but the message does not arrive. Does anybody know why this could be happening?
Your server is expecting a complete line terminated by a newline. Try:
bw.write("Hello Server!");
bw.newLine();
Do it like this...
String s = new String();
while ((br.readLine())!=null) {
s = s+br.readLine();
System.out.print("Received message: ");
System.out.println(input);
}
}
And
bw.println("Hello Server");
I notice that you don't send an endline on your client, so the BufferedReader.readline() will never return, because it cannot match the \n-character. Try it again with
bw.write("Hello Server!\n");
on the client side.
how to reuse TCP Socket connection(possible setReuseAddress(true), but not work for me) for download multiple files from Server(Apache, HTTPD) in on connection without disconnect(and connect again).
My code below..
public class ClientThread implements Runnable {
public void run() {
try {
Log.d("ClientActivity", "C: Connecting...");
SocketAddress sockaddr = new InetSocketAddress(serverIpAddress, SERVERPORT);
socket = new Socket();
socket.setReuseAddress(true);
socket.setKeepAlive(true);
socket.setSoLinger(true, 3000);
socket.connect(sockaddr);
if (socket.isConnected()) {
DataInputStream input = new DataInputStream(socket.getInputStream());
PrintWriter output = new PrintWriter(new OutputStreamWriter(socket.getOutputStream()));
output.println("GET /way/images/profile/1231 HTTP/1.1");
output.println("Host: 192.168.1.2");
output.println("User-Agent: Java");
output.println("Accept: */*");
output.println("Connection: Keep-Alive");
output.println("");
output.flush();
String line;
File file = new File("/sdcard/aaa.png");
if (!file.exists()) {
file.createNewFile();
}
FileOutputStream fileOut = new FileOutputStream(file);
System.out.println("Getting first file");
while ( (line = input.readLine()) != null ) {
System.out.println(line);
fileOut.write(line.getBytes());
}
System.out.println("First file finished");
fileOut.flush();
fileOut.close();
output.println("GET /way/images/profile/1231 HTTP/1.1");
output.println("Host: 192.168.1.2");
output.println("User-Agent: Java");
output.println("Accept: */*");
output.println("Connection: Keep-Alive");
output.println("");
output.flush();
file = new File("/sdcard/aaa1.png");
if (!file.exists()) {
file.createNewFile();
}
fileOut = new FileOutputStream(file);
System.out.println("Getting second file");
while ( (line = input.readLine()) != null ) {
System.out.println(line);
fileOut.write(line.getBytes());
}
System.out.println("Second file finished");
fileOut.flush();
fileOut.close();
input.close();
output.close();
}
Log.d("ClientActivity", "C: Closed.");
} catch (Exception e) {
Log.e("ClientActivity", "C: Error", e);
connected = false;
}
finally {
try {
Log.d("ClientActivity", "Socket: Closed.");
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
Thanks...
setReuseAddress(true) prior to binding the socket allows the socket to be bound even though a previous connection is in a timeout state.
documentation of setReuseAddress
I don't see sense in directly using socket for HTTP communication. I use HttpURLConnection. Works without problems in most cases.