I try to create a client server socket beetwen my droid(client) and my PC(server), when i am in local(over wifi) it work perfectely, but when il try over 3G i get this exception when the server try to get clientsocket.getOutputStream()
at java.lang.Thread.run(Unknown Source)
java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(Unknown Source)
at java.net.SocketInputStream.read(Unknown Source)
at java.io.DataInputStream.readUnsignedShort(Unknown Source)
at java.io.DataInputStream.readUTF(Unknown Source)
at java.io.DataInputStream.readUTF(Unknown Source)
What’s the probleme, do eny one know the solution of this?
help please 🙁
The Server
public class Server {
ServerSocket serverSocket;
public LinkedBlockingQueue<CDRecCourseDisplay> recCours;
public LinkedList<ClientMail> clientMails;
static Server server;
public static Server getInstance(){
if(server == null){
server = new Server();
}
return server;
}
Server() {
// TODO Auto-generated constructor stub
try {
serverSocket = new ServerSocket(54444);
recCours = new LinkedBlockingQueue<CDRecCourseDisplay>(10);
clientMails = new LinkedList<ClientMail>();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
this.start();
}
private void start(){
new Thread(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
while (true){
try {
Socket socket = serverSocket.accept();
new Thread(new Client(socket)).start();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}).start();
}
class Client implements Runnable{
Socket socket;
DataInputStream in;
DataOutputStream out;
public Client(Socket socket) {
// TODO Auto-generated constructor stub
this.socket = socket;
if(socket == null) return;
try {
InputStream i = socket.getInputStream();
OutputStream o = socket.getOutputStream();
in = new DataInputStream(i);
out = new DataOutputStream(o);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
@Override
public void run() {
// TODO Auto-generated method stub
new Thread(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
while(true){
try {
out.writeUTF("Test Message");
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}).start();
new Thread(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
while(true){
try {
String buf = in.readUTF();
Log.d("MESSAGE", buf);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}).start();
}
}
}
and the client
class Client implements Runnable{
Socket socket;
DataInputStream in;
DataOutputStream out;
public void run() {
// TODO Auto-generated method stub
boolean conected = false;
while(!conected){
try {
Thread.sleep(500);
socket = new Socket("213.233.216.25", 54444);
in = new DataInputStream(socket.getInputStream());
out = new DataOutputStream(socket.getOutputStream());
conected = true;
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
Log.e("ERROR :", e.getMessage());
} catch (IOException e) {
// TODO Auto-generated catch block
Log.e("ERROR :", e.getMessage());
} catch (InterruptedException e) {
// TODO Auto-generated catch block
Log.e("ERROR :", e.getMessage());
}
}
new Thread(new Runnable() {
public void run() {
// TODO Auto-generated method stub
while(true){
try {
String buf = in.readUTF();
log.d("MESSAGE", buf);
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}).start();
new Thread(new Runnable() {
public void run() {
// TODO Auto-generated method stub
while(true){
try {
out.writeUTF("Test message from the phone");
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}).start();
}
}
Most networks (Wifi and 3G) use NAT. NAT allows outbound connections, but prevents inbound (internet to device) connections.
When your server and device are both on the same network, as in your case, then this works as you are not traversing NAT gateway.
Rationale: what you are trying to do (connecting from internet to device) will not work in most networks.