Java, problem sending a message with socket connection
I have a problem with my Java program. It has a socket connection between a server and many client. Here is the server (the part which concerns the problem):
private static ArrayList<ParallelServer> clientConnected = new ArrayList<ParallelServer>();
public Server(int port) {
this.port = port;
if (!startServer())
JOptionPane.showMessageDialog(new JFrame(""),
"Error!", "ERROR!",
JOptionPane.ERROR_MESSAGE);
}
private boolean startServer() {
try {
server = new ServerSocket(port);
loadDatabase();
} catch (IOException ex) {
ex.printStackTrace();
return false;
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
return true;
}
public void runServer() {
while (true) {
try {
client = server.accept();
ParallelServer pServer = new ParallelServer(client);
clientConnected.add(pServer);
Thread thread = new Thread(pServer);
thread.start();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
public static void sendBroadcast(String username) throws IOException {
for(int i = 0; i < clientConnected.size(); i++)
clientConnected.get(i).sendAnswer("@change," + username);
}
The parallel server is:
private Socket client;
private InputStreamReader inputstreamreader;
private BufferedReader bufferedreader;
private PrintWriter printwriter;
public ParallelServer(Socket client) {
this.client = client;
}
public void run() {
try {
inputstreamreader = new InputStreamReader(client.getInputStream());
bufferedreader = new BufferedReader(inputstreamreader);
printwriter = new PrintWriter(client.getOutputStream(), true);
String lineread = "";
while (client.isConnected()) {
lineread = bufferedreader.readLine();
doCommand(lineread);
}
} catch (UnknownHostException unhe) {
} catch (InterruptedIOException intioe) {
} catch (IOException ioe) {
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
public void sendAnswer(String answer) throws IOException {
printwriter = new PrintWriter(client.getOutputStream(), true);
printwriter.println(answer);
printwriter.flush();
}
And here is the client:
private String serverurl = "localhost";
private int serverport = 7777;
private PrintWriter printwriter;
private InputStreamReader inputstreamreader;
private BufferedReader bufferedreader;
private Socket server;
public Client() {
server = null;
try {
server = new Socket(serverurl, serverport);
server.setSoTimeout(5000);
} catch (UnknownHostException unhe) {
System.out.println("UnknownHostException: " + unhe.getMessage());
} catch (InterruptedIOException intioe) {
System.out.println("Timeout while attempting to establish socket connection.");
} catch (IOException ioe) {
JOptionPane.showMessageDialog(new JFrame(),"Unable to reach the server!","ERROE!",JOptionPane.ERROR_MESSAGE);
}
}
public String sendCommand(String command) throws IOException {
if(server == null) {
try {
server = new Socket(serverurl, serverport);
server.setSoTimeout(5000);
} catch (UnknownHostException unhe) {
System.out.println("UnknownHostException: " + unhe.getMessage());
} catch (InterruptedIOException intioe) {
System.out.println("Timeout while attempting to establish socket connection.");
} catch (IOException ioe) {
JOptionPane.showMessageDialog(new JFrame(),"Unable to reach the server!","ERROR!",JOptionPane.ERROR_MESSAGE);
}
}
if(server != null) {
printwriter = new PrintWriter(server.getOutputStream(), true);
printwriter.println(command);
printwriter.flush();
inputstreamreader = new InputStreamReader(server.getInputStream());
bufferedreader = new BufferedReader(inputstreamreader);
return bufferedreader.readLine();
}
else
return "@serverProblem";
}
The program is a simple online game with turns. Players' turns are created with a queue and when a player passes his turn, the server send a broadcast message which say "Now it is 'Player 1' turn." (for instance). My problem is that when a client receive the message, its like it add the answer "Now it is 'Player 1' turn." to the next message it will receive. In my case: when a player passes his turn, he sends "@passTurn,username". The ParallelServer class polls it from the queue, puts it at the bottom of the queue, sends the client "@ok" to tell it that the turn has changed successfully and tells开发者_运维技巧 the Server class to send the broadcast message. Then, when the same client will try do do a further action, it will consider "Now it is 'Player 1' turn." as the answer the server has given to it. Instead, I would like that the server and the clients work as always and when the broadcast message is cought, the client is notified without any collateral effect. What can I do? Thanks.
Your bi-directional message passing mechanism should look something like this:
Server:
Wait on any client InputStream
if (broadcast)
broadcast_message()
else
process_message()
Client:
Receiving Thread:
Wait on server broadcast
Sending Thread:
Wait on messages to be sent to server from the User Input
This should do the trick :)
Hope it helps. Cheers!
精彩评论