I'm trying to send data through UDP each 20ms and It's working properly.
But, as I try to use TCP it's not working well and the app gives me the not responding error!
Following code is for sending through UDP
public class sMessage implements Runnable {
#Override
public void run() {
try {
DatagramSocket s = new DatagramSocket();
InetAddress local = InetAddress.getByName("192.168.16.254");
int msg_length=messageStr.length();
byte[] message = messageStr.getBytes();
DatagramPacket p = new DatagramPacket(message, msg_length,local,server_port);
s.send(p);
} catch (IOException e) {
Log.e(TAG, "ERROR");
}
}
}
And I use the same Runnable for TCP, but not working correctly!
public class sMessage implements Runnable {
#Override
public void run() {
try {
Log.v(TAG, "send");
InetAddress serverAddr = InetAddress.getByName(SERVERIP);
Socket socket = new Socket(serverAddr, 5000);//create a socket
DataOutputStream os = new DataOutputStream(socket.getOutputStream());
PrintWriter ot = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())), true);
String s = "1";
//s+="\r\n";
//byte[] bytes = s.getBytes("UTF-8");
//os.writeChar(1);
//os.writeBytes(text);
//os.writeUTF(String.valueOf("123"));
ot.println(text);
ot.flush();
ot.close();
os.flush();
os.close();
socket.close();
} catch (IOException e) {
Log.e(TAG, "ERROR");
}
}
}
My goal is to send data each 10ms by using TCP!
why it is not working properly!??
Thanks in advance for your replies
Related
Can somebody explain to me what I am doing wrong.First time I try to implement TCP between Java and C#:
Sever code c#
`
public void CreateServer()
{
Thread thread = new Thread(() =>
{
IPAddress addr = IPAddress.Parse(localIP);
tcpListener = new TcpListener(addr, 5053);
if (tcpListener != null)
{
tcpListener.Start();
while (!end)
{
TcpClient tcpClient = tcpListener.AcceptTcpClient();
var ip = ((IPEndPoint)tcpClient.Client.RemoteEndPoint).Address.ToString();
Console.WriteLine("Client connected from "+ip);
NetworkStream clientStream = tcpClient.GetStream();
StreamReader reader = new StreamReader(clientStream, Encoding.UTF8);
try
{
string request = reader.ReadToEnd();
Console.WriteLine("Message from client: " + request);
Byte[] StringToSend = Encoding.UTF8.GetBytes("Server");
clientStream.Write(StringToSend, 0, StringToSend.Length);
Console.WriteLine("Sending response back");
}
catch (Exception e)
{
Console.WriteLine(e);
}
}
}
});
thread.Start();
}
`
Client code java
`
public class TCP {
private String IP;
private InetAddress server;
private Socket socket;
public TCP(String IP) {
this.IP = IP;
}
protected void runTCP() {
try {
server = InetAddress.getByName(IP);
socket = new Socket(server, 5053);
System.out.println("Client connected. Listening on port 5053");
} catch (Exception e) {
e.printStackTrace();
}
}
public void sendMessage(String message) {
try {
System.out.println("Sending data...");
if (socket.isClosed()) socket = new Socket(server, 5053);
PrintWriter writer = new PrintWriter(socket.getOutputStream());
writer.print(message);
writer.flush();
writer.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public void getResponseServer() {
Thread thread = new Thread() {
#Override
public void run() {
try {
System.out.println("Attempting to get response...");
if (socket.isClosed()) socket = new Socket(server, 5053);
BufferedReader mBufferIn = new BufferedReader(new InputStreamReader(socket.getInputStream()));
String mServerMessage = mBufferIn.readLine();
System.out.println("Server message: " + mServerMessage);
} catch (Exception e) {e.printStackTrace();}
}
};
thread.start();
}
}
`
Output on server I get when sending "Hello" from client to server:
Client connected from 192.16.... Message from client: Hello Sending response back Client connected from 192.16....
Output on client:
Client connected. Listening on port 5053 Sending data... Attempting to get response...
Never gets response... Why?
Tried researching but found nothing yet, tried other code but didnt work aswell...
sorry , I can't comment. maybe you can use telnet command to vertify c# code is corrent.
telnet ip port
first, locate problem, then solve it.
if server is ok , we can use nc command vertify client code, I have test your java code , except every send data will close socket , other is ok.
Fixed it by removing writer.close() cause that causes socket closing and makes another connection to the server by creating again the socket which makes the server wait for a stream of data and the client wait for a response...
System.out.println("Sending data...");
PrintWriter writer = new PrintWriter(socket.getOutputStream(), true);
writer.println(message);
InputStream input = socket.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(input));
String line;
while ((line = reader.readLine()) != null) {
System.out.println(line);
}
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 tried to write a simple program that runs a server and then accepts two clients. Then one of them tries to send a string to another client.
but my code doesn't work and I don't know why.
This is my TestClient class:
public class TestClient extends Thread{
int id;
String Name;
Socket client;
boolean isAsk;
public TestClient(int id,String clientName,boolean isAsk) throws IOException {
this.id=id;
this.Name=clientName;
this.isAsk=isAsk;
}
public void connectTheClientToTheLocalHost(ServerSocket server){
try {
client = new Socket("localhost",1111);
server.accept();
} catch (IOException e) {
e.printStackTrace();
}
}
public void readFromTerminal(){
try {
InputStream is=client.getInputStream();
OutputStream os = client.getOutputStream();
PrintWriter pw = new PrintWriter(os);
pw.println("sdklfsdklfk");
pw.flush();
pw.close();
}catch (IOException e){
e.printStackTrace();
}
}
public void closeTheCientSocket(){
try {
client.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public void write(){
try {
Scanner sc = new Scanner(client.getInputStream());
BufferedWriter bw = new BufferedWriter(new FileWriter(new File("file1.txt")));
String st =sc.nextLine();
bw.write(st);
bw.close();
}catch (IOException e){
e.printStackTrace();
}
}
#Override
public void run() {
if(isAsk){
readFromTerminal();
}
else{
write();
}
}
and this is the main function:
public class PCServer {
public static void main(String[] args){
try {
ServerSocket s = new ServerSocket(1111);
TestClient t1=(new TestClient(1,"reza",true));
TestClient t2=(new TestClient(2,"man",false));
t1.connectTheClientToTheLocalHost(s);
t1.start();
Scanner sc = new Scanner(t1.client.getInputStream());
String st=sc.nextLine();
System.out.println(st);
t1.closeTheCientSocket();
t2.connectTheClientToTheLocalHost(s);
PrintWriter pw = new PrintWriter(t2.client.getOutputStream());
pw.println(st);
pw.flush();
t2.start();
t2.closeTheCientSocket();
}catch (Exception e){
e.printStackTrace();
}
}
}
actually this code returns an exception in
String st=sc.nextLine();
in main function and says that there is no line found.
what is the problem?
ServerSocket in java usually used in another way.
If you need point-to-point connection, one host creates a ServerSocket and accepts connections. Examples:
First host example:
try(ServerSocket serverSocket = new ServerSocket(5555);
Socket socket = serverSocket.accept();
// it more convenient to use DataInputStream instead of Scanner I think
DataInputStream dataInputStream = new DataInputStream(socket.getInputStream());
DataOutputStream dataOutputStream = new DataOutputStream(socket.getOutputStream());) {
while (!Thread.currentThread().isInterrupted()) {
String msg = dataInputStream.readUTF();
System.out.println("got request: " + msg);
dataOutputStream.writeUTF("1-response");
dataOutputStream.flush();
}
} catch (IOException e) {
e.printStackTrace();
}
Second host example:
try(Socket socket = new Socket("127.0.0.1", 5555);
DataInputStream dataInputStream = new DataInputStream(socket.getInputStream());
DataOutputStream dataOutputStream = new DataOutputStream(socket.getOutputStream())) {
while (!Thread.currentThread().isInterrupted()) {
dataOutputStream.writeUTF("2-request");
dataOutputStream.flush();
String msg = dataInputStream.readUTF();
System.out.println("got response: " + msg);
}
} catch (IOException e) {
e.printStackTrace();
}
If you want one host talk to another over the server (broker), then you need plane java Sockets on hosts and ServerSocket on broker, and broker must transmit messages it received from one host to another. Examples:
Broker (run it in separate thread or process)
try {
List<Socket> sockets = new ArrayList<>();
ServerSocket serverSocket = new ServerSocket(5555);
// accepting connections from 2 clients
for (int i = 0; i < 2; i++) {
Socket socket = serverSocket.accept();
sockets.add(socket);
}
// streams for first host
InputStream hostOneInputStream = sockets.get(0).getInputStream();
DataInputStream hostOneDataInputStream = new DataInputStream(sockets.get(0).getInputStream());
DataOutputStream hostOneDataOutputStream = new DataOutputStream(sockets.get(0).getOutputStream());
// streams for second host
InputStream hostTwoInputStream = sockets.get(1).getInputStream();
DataInputStream hostTwoDataInputStream = new DataInputStream(sockets.get(1).getInputStream());
DataOutputStream hostTwoDataOutputStream = new DataOutputStream(sockets.get(1).getOutputStream());
while (!Thread.currentThread().isInterrupted()) {
if (hostOneInputStream.available() > 0) {
String msg = hostOneDataInputStream.readUTF();
System.out.println("got message from host 1: " + msg);
hostTwoDataOutputStream.writeUTF(msg);
hostTwoDataOutputStream.flush();
System.out.println("message " + msg + " sent to host two");
}
if (hostTwoInputStream.available() > 0) {
String msg = hostTwoDataInputStream.readUTF();
System.out.println("got message from host 2: " + msg);
hostOneDataOutputStream.writeUTF(msg);
hostOneDataOutputStream.flush();
System.out.println("message " + msg + " sent to host one");
}
}
} catch (IOException e) {
e.printStackTrace();
}
First host (run it in separate thread or process)
try(Socket socket = new Socket("127.0.0.1", 5555);
DataInputStream dataInputStream = new DataInputStream(socket.getInputStream());
DataOutputStream dataOutputStream = new DataOutputStream(socket.getOutputStream())) {
while (!Thread.currentThread().isInterrupted()) {
dataOutputStream.writeUTF("1");
dataOutputStream.flush();
String msg = dataInputStream.readUTF();
System.out.println("got msg: " + msg);
TimeUnit.SECONDS.sleep(5);
}
} catch (IOException | InterruptedException e) {
e.printStackTrace();
}
Second host (run it in separate thread or process)
try(Socket socket = new Socket("127.0.0.1", 5555);
DataInputStream dataInputStream = new DataInputStream(socket.getInputStream());
DataOutputStream dataOutputStream = new DataOutputStream(socket.getOutputStream())) {
while (!Thread.currentThread().isInterrupted()) {
String msg = dataInputStream.readUTF();
System.out.println("got msg: " + msg);
TimeUnit.SECONDS.sleep(5);
dataOutputStream.writeUTF("2");
dataOutputStream.flush();
}
} catch (IOException | InterruptedException e) {
e.printStackTrace();
}
i'm using TCP socket to send and receive data from the same socket in the same activity through client server thread, the purpose of that is to send a string to other device and that string will trigger a notification once the other device receives it then that device will replay with something like dismiss or accepted, the problem that i'm having is after sending the string the other device receives it and send the dismiss or accepted String but my divice doesn't receive that string i guess there is a problem in my ServerThread be aware that the server thread and client thread are in the same activity used as an inner classes and get called in a button.
code:
ClientThread
private class ChatClientThread extends Thread {
#Override
public void run() {
Socket socket = null;
DataOutputStream dataOutputStream = null;
try {
socket = new Socket("192.168.0.113", 23);
dataOutputStream = new DataOutputStream(
socket.getOutputStream());
dataOutputStream.writeUTF(" "+"SolveProblemOrder_2");
dataOutputStream.flush();
ServerThread serv =new ServerThread();
serv.start();
} catch (UnknownHostException e) {
e.printStackTrace();
final String eString = e.toString();
TicketDetails.this.runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(TicketDetails.this, eString, Toast.LENGTH_LONG).show();
}
});
} catch (IOException e) {
e.printStackTrace();
final String eString = e.toString();
TicketDetails.this.runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(TicketDetails.this, eString, Toast.LENGTH_LONG).show();
}
});
} finally {
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (dataOutputStream != null) {
try {
dataOutputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
TicketDetails.this.runOnUiThread(new Runnable() {
#Override
public void run() {
}
});
}
}
}
ServerThread
public class ServerThread extends Thread {
private ServerSocket serverSocket;
private Socket clientSocket;
public void run(){
try{
// Open a server socket listening on port 23
InetAddress addr = InetAddress.getByName(getLocalIpAddress());
serverSocket = new ServerSocket(23, 0,addr);
try{
clientSocket = serverSocket.accept();
DataInputStream dataInputStream = new DataInputStream(clientSocket.getInputStream());
String newMsg = null;
Toast.makeText(getApplicationContext(), newMsg, Toast.LENGTH_LONG).show();
// Client established connection.
// Create input and output streams
while (true) {
if (dataInputStream.available() > 0) {
newMsg = dataInputStream.readUTF();
}
}}catch(Exception e){
e.printStackTrace();
}
// Perform cleanup
} catch(Exception e) {
// Omitting exception handling for clarity
}
}
private String getLocalIpAddress() throws Exception {
String resultIpv6 = "";
String resultIpv4 = "";
for (Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces();
en.hasMoreElements();) {
NetworkInterface intf = en.nextElement();
for (Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses();
enumIpAddr.hasMoreElements();) {
InetAddress inetAddress = enumIpAddr.nextElement();
if(!inetAddress.isLoopbackAddress()){
if (inetAddress instanceof Inet4Address) {
resultIpv4 = inetAddress.getHostAddress().toString();
} else if (inetAddress instanceof Inet6Address) {
resultIpv6 = inetAddress.getHostAddress().toString();
}
}
}
}
return ((resultIpv4.length() > 0) ? resultIpv4 : resultIpv6);
}
}
i start those two threads in a button Click listener:
ChatClientThread chatClient=new ChatClientThread();
chatClient.start();
ServerThread serv =new ServerThread();
serv.start();
if this won't work using server/client in the same activity using the same port is there any other way to listen to a socket like is there a built in listener or something like that.
any help is appreciated
You write to socket thru socket.getOutputStream() and you must read from InputStream of socket.getInputStream() ;
You can adapt your code .
Your server use InputStream from socket to read data ,so you must to do also in your client code , cause you want also to receive data not only to send.
check this out just read is is very simple.
https://systembash.com/a-simple-java-tcp-server-and-tcp-client/
See the code for reading from socket taht start with :
BufferedReader inFromClient =
new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));
and code for writing to socket:
DataOutputStream outToClient = new DataOutputStream(connectionSocket.getOutputStream());
or search google : java client server .
The ideea is that you send data to the socket outputstream and you can read it from same socket inputstream.
you see here example it read data from socket input and send data thru socket output , to server
String sentence;
String modifiedSentence;
BufferedReader inFromUser = new BufferedReader( new InputStreamReader(System.in));
Socket clientSocket = new Socket("localhost", 6789);
DataOutputStream outToServer = new DataOutputStream(clientSocket.getOutputStream());
BufferedReader inFromServer = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
sentence = inFromUser.readLine();
outToServer.writeBytes(sentence + '\n');
modifiedSentence = inFromServer.readLine();
System.out.println("FROM SERVER: " + modifiedSentence);
clientSocket.close();
This question already has answers here:
How can I fix 'android.os.NetworkOnMainThreadException'?
(66 answers)
Closed 7 years ago.
the class of client in android application (using emulator localhost), sending a string to my java application (serveur) :
public class Client_socket extends MainActivity{
private static Socket socket;
public static void lance()
{
try
{
String host = "localhost";
int port = 25000;
InetAddress address = InetAddress.getByName(host);
socket = new Socket("127.0.0.3", port);
//Send the message to the server
OutputStream os = socket.getOutputStream();
OutputStreamWriter osw = new OutputStreamWriter(os);
BufferedWriter bw = new BufferedWriter(osw);
String nom = "premiere";
String sendMessage = ism + "\n";
bw.write(sendMessage);
bw.flush();
System.out.println("Message sent to the server : "+sendMessage);
//Get the return message from the server
InputStream is = socket.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String message = br.readLine();
System.out.println("Message received from the server : " +message);
}
catch (Exception exception)
{
exception.printStackTrace();
}
finally
{
//Closing the socket
try
{
socket.close();
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
}
the class of serveur in java application how recive my string :
what the ip and port can i use?, and how can i get my ip?
public class Server
{
private static Socket socket;
public static void main(String[] args)
{
try
{
int port = 25000;
ServerSocket serverSocket = new ServerSocket(port);
System.out.println("Server Started and listening to the port 25000");
//Server is running always. This is done using this while(true) loop
while(true)
{
//Reading the message from the client
socket = serverSocket.accept();
InputStream is = socket.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String nom = br.readLine();
System.out.println("Message received from client is "+nom);
}
}
catch (Exception e)
{
e.printStackTrace();
}
finally
{
try
{
socket.close();
}
catch(Exception e){}
}
}
}
Make sure you execute network operations in a background thread:
new Thread(new Runnable() {
#Override
public void run() {
lance(); // call your network method here
}
}).start();