I am trying to make a socket server, I am connecting through putty to this server. Whenever I type "hi" it says "no" rather than "hi" which I want it to do. I found this on A java website. If you could tell me what I am doing wrong that would be great. Thanks!
int port = 12345;
ServerSocket sock = new ServerSocket(port);
System.out.println("Server now active on port: " + port);
Socket link = sock.accept();
System.out.println("Interface accepted request, IP: " + link.getInetAddress());
BufferedReader input = new BufferedReader(new InputStreamReader(link.getInputStream()));
PrintWriter output = new PrintWriter(link.getOutputStream(), true);
output.println("ISEEYOU");
String inputLine;
Thread.sleep(1500);
while((inputLine = input.readLine()) != null) {
if(inputLine.equals("hi")) {
output.println("hi");
}else{
output.println("no");
}
}
Your Java program is correct.
I've tried your code, just added System.out.printf("[%s]", inputLine); as first line in the while loop to ensure, what I get from putty.
I guess your problem is the protocol putty uses to connect. It worked with RAW for me. See below the session setting I've used:
EDIT:
According to your comment I added some code for a simple client, that reads the line from console, sends it to the server and prints the echo back to console.
public void Client() throws IOException {
// Client that closes the communication when the user types "quit"
Socket socket = new Socket("localhost", 8080);
BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
PrintStream ps = new PrintStream(socket.getOutputStream());
BufferedReader user = new BufferedReader(new InputStreamReader(System.in));
String line;
while(!(line = user.readLine()).equals("quit")) {
ps.println(line); // Write to server
System.out.println(reader.readLine()); // Receive echo
}
socket.shutdownOutput(); // Send EOF to server
socket.close();
}
The corresponding server would look like this:
public void server() throws IOException {
ServerSocket serverSocket = new ServerSocket(8080);
Socket socket = serverSocket.accept();
BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
PrintStream ps = new PrintStream(socket.getOutputStream());
// Just read a line and echo it till EOF
String line;
while((line = reader.readLine()) != null) ps.println(line);
}
You might need to change the port I used here, if 8080 is already binded on your machine. Also you might want to have the server running on another computer then the client. In this case you need to change "localhost".
Related
I am running a client server program on port 80 (currently says port 2040 for testing purposes only). Whenever I run my server on my client side/browser, the console displays this weird text, when it should be returning a HTMl file that i scannned in. However, when I run my IP address on my browser, it returns the necessary code. Why?
Here is my code:
public class ServerSide {
public static void main(String[] args) throws Exception {
//port used
int port = 2040;
ServerSocket serverSocket = new ServerSocket(port);
System.out.println("Running on port " +port);
/*server always on
* creating a connection socket when contacted by client..
*/
while(true) {
//create connection socket when contacted
Socket client = serverSocket.accept();
//read input from client
BufferedReader input = new BufferedReader(new InputStreamReader(client.getInputStream()));
//whatever input or communication we want to have can operate in this string..
String x;
while((x = input.readLine()) != null){
System.out.println(x);
if(x.isEmpty()) {
break;
}
}
//output of client server..
OutputStream clientOutput = client.getOutputStream();
clientOutput.write("HTTP/1.1 200 OK\r\n".getBytes());
clientOutput.write("\r\n".getBytes());
clientOutput.write("".getBytes());
clientOutput.write("\r\n\r\n".getBytes());
Scanner fetch = new Scanner(new File("index.html"));
String myHTML_file = fetch.useDelimiter("\\Z").next();
fetch.close();
clientOutput.write(myHTML_file.getBytes("UTF-8"));
clientOutput.write("\r\n\r\n".getBytes());
clientOutput.flush();
System.out.println("Connection closed.");
clientOutput.close();
}
}
}
I'm learning some Java socket programming and I've managed to make my first ever connection between Server and Client. That sparked a curiosity in me: what would happen if instead of the "Connected" and "Message Received" messages I made a sort of "chat room" type thing, where server and client inputs are printed to one another? So I tried doing just that.
Now, I know this isn't the way chat rooms are created (I'd probably need Threads and whatnot), but I was very curious as to why this didn't work:
Server:
public void run() throws Exception
{
boolean isChatting = true;
Socket clientSocket = new Socket("localhost", 444);
PrintStream ps = new PrintStream(clientSocket.getOutputStream());
ps.println("Connected.");
BufferedReader bfr = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
BufferedReader bfrClient = new BufferedReader(new InputStreamReader(System.in));
String serverMessage = bfr.readLine();
String clientMessage;
System.out.println("Server: "+serverMessage);
while (isChatting)
{
clientMessage = bfrClient.readLine();
ps.println(clientMessage);
if (clientMessage.toUpperCase().equals("EXIT"))
{
isChatting = false;
}
}
bfr.close();
bfrClient.close();
}
Client:
public void run() throws Exception
{
boolean isChatting = true;
ServerSocket server = new ServerSocket(444); //Port
Socket sSocket = server.accept();
PrintStream ps = new PrintStream(sSocket.getOutputStream());
BufferedReader bfr = new BufferedReader(new InputStreamReader(sSocket.getInputStream()));
BufferedReader bfrPersonal = new BufferedReader(new InputStreamReader(System.in));
String clientMessage = bfr.readLine();
String messageToSend;
System.out.println("Client: "+clientMessage);
if (clientMessage != null)
{
ps.println("Connected.");
}
while (isChatting)
{
messageToSend = bfrPersonal.readLine();
ps.println(messageToSend);
if (messageToSend.toUpperCase().equals("EXIT"))
{
isChatting = false;
}
}
bfr.close();
bfrPersonal.close();
}
Thank you for your time! :)
If you like to create a chat system the easiest way is to create two threads on the server and two threads on the client side.
The first thread handle the input of the user and send it.
The second thread handle the input from the other chat system and print it.
I am using Sockets to connect using TCP and I want to make different calls. e.g. Get InputValue
I have these type of different requests which I want to make from already running server.
Socket client = new Socket(serverName, port);
System.out.println("Just connected to "
+ client.getRemoteSocketAddress());
OutputStream outToServer = client.getOutputStream();
DataOutputStream out = new DataOutputStream(outToServer);
String func="Get inputvalue";
byte[] tRequest = encoder.string2bytes(func);
out.write(tRequest);
out.flush();
System.out.println("write done");
InputStream inFromServer = client.getInputStream();
DataInputStream in =
new DataInputStream(inFromServer);
System.out.println("Server says " + in.readUTF());
It says it connected as just connected printout got printed. Write done print is also printed but no data is returned and the program keeps on running.
If I use telnet then this same request call returns data successfully.
So the question is how to make TCP calls in java?
Update: I solved this by:
PrintWriter toServer =
new PrintWriter(client.getOutputStream(),true);
BufferedReader fromServer =
new BufferedReader(
new InputStreamReader(client.getInputStream()));
toServer.println("Get inputvalue\r\n");
String line = "";
System.out.println("Client received: ");
while ((line = fromServer.readLine()) != null) {
System.out.println(line);
}
but the program keeps on running in the while loop and prints nothing. how to check that response is ended?
So I am trying to have a sever sit and listen waiting for a connection from a client. The client sends over some string and the sever does some action based on whats received. Now what I would like to happen is the client sends over some command asking for data back and have the server get what it needs to and send the string back.
Not a big deal right? Well for some reason I can't get it working, my best guess is that its not closing the socket properly. I can't figure out why it wouldn't or what I am doing wrong.
Client
String data = "";
DataOutputStream outToServer = null;
BufferedReader input;
try {
outToServer = new DataOutputStream(clientSocket.getOutputStream());
outToServer.writeBytes("GETDATA");
outToServer.flush();
input = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
data = input.readLine();
Log.d("ANSWER: ", data);
input.close();
} catch (IOException e) {
Log.d("Error: ", e.toString());
}
Server
ServerSocket listeningSocket = new ServerSocket(9008);
BufferedReader fromClient ;
PrintStream os;
while(true) {
Socket clientSocket = listeningSocket.accept();
ServerConnection clientConnection = new ServerConnection(clientSocket);
os = new PrintStream(clientSocket.getOutputStream());
fromClient= new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
if(fromClient.readLine().equals("GETDATA")){
os.println("DATA");
os.flush();
clientSocket.wait();
clientSocket.close();
}
else{
clientConnection.run();
}
}
Any ideas?
here is your error
outToServer.writeBytes("GETDATA");
the right code is
outToServer.writeBytes("GETDATA\n");
as your using readline you should send a full line with line break
I have 2 classes (Client and Server) used to implement simple communication in my application. My code is shown below:
Server:
public class Server {
public static void main(String[] ar) {
int port = 1025; // just a random port. make sure you enter something between 1025 and 65535.
try {
ServerSocket ss = new ServerSocket(port); // create a server socket and bind it to the above port number.
System.out.println("Waiting for a client...");
Socket socket = ss.accept();
InputStream sin = socket.getInputStream();
OutputStream sout = socket.getOutputStream();
DataInputStream in = new DataInputStream(sin);
DataOutputStream out = new DataOutputStream(sout);
BufferedReader keyboard = new BufferedReader(new InputStreamReader(
System.in));
System.out.println("enter meter id ");
String line = null;
while (true) {
line = in.readUTF(); // wait for the client to send a line of text.
System.out.println("client send me this id number " + line);
line = keyboard.readLine();
out.writeUTF(line);
out.flush();
//line = in.readUTF();
System.out.println("Waiting for the next line...");
System.out.println();
}
} catch (Exception x) {
x.printStackTrace();
}
}
}
Client:
public class Client {
public static void main(String[] ar) {
int serverPort = 1025;
String address = "localhost";
try {
InetAddress ipAddress = InetAddress.getByName(address); // create an object that represents the above IP address.
System.out.println(" IP address " + address + " and port "
+ serverPort);
Socket socket = new Socket(ipAddress, serverPort); // create a socket with the server's IP address and server's port.
InputStream sin = socket.getInputStream();
OutputStream sout = socket.getOutputStream();
DataInputStream in = new DataInputStream(sin);
DataOutputStream out = new DataOutputStream(sout);
// Create a stream to read from the keyboard.
BufferedReader keyboard = new BufferedReader(new InputStreamReader(
System.in));
String line = null;
System.out.println("ClientConnected.");
System.out.println("enter meter id");
while (true) {
line = keyboard.readLine(); // wait for the user to type in something and press enter.
System.out.println("Sending this number to the server...");
out.writeUTF(line); // send the above line to the server.
out.flush(); // flush the stream to ensure that the data reaches the other end.
line = in.readUTF(); // wait for the server to send a line of text.
System.out
.println("The server was very polite. It sent me this : "
+ line);
System.out.println();
}
}
catch (Exception x) {
x.printStackTrace();
}
}
}
My problem is that while testing the program I do get communication between the client and server, but while debugging, with a break point on the out.flush line in Server.java, it does not go to the intended destination. This intended destination being the line line = in.readUTF(); of Client.java. Can anyone help me to solve this?
It is good practice to open the OutputStreams before the InputStreams, on your sockets, as said in this question.
This question also clarifies that.
What I suspect here is your client and server are running in two different JVM processes and java debugger cannot debug two JVM at the same time.