I am trying to connect a client with gui with a server withoout gui. Connection is being done, but i cant see any messages between these two apps. (i should get SERVER HERE in client, and CLIENT HERE in server)
Client Connection Code:
@Override
public void ClientRunning(){
try {
connectToServer();
setStreams();
ClientRun();
}catch(EOFException oefException){
showMessage("\n Client terminated the connection\n");
}catch(IOException ioException){
ioException.printStackTrace();
}finally{
close();
}
}
public void connectToServer() throws IOException{
showMessage("Attempting Connection... \n");
connection = new Socket(InetAddress.getByName(serverIP),6789);
showMessage("Connected to: "+ connection.getInetAddress().getHostName());
}
public void setStreams() throws IOException{
output = new PrintWriter(connection.getOutputStream(),true);
output.flush();
input= new BufferedReader(new InputStreamReader(connection.getInputStream()));
showMessage("\n Streams are now set. \n");
}
public void close(){
showMessage("\n closing...");
try{
output.close();
input.close();
connection.close();
}catch(IOException ioException){
ioException.printStackTrace();
}
}
public void showMessage(final String text){
SwingUtilities.invokeLater(new Runnable(){
public void run(){
cwindow.append(text);
}
});
}
public void sendMessage(String message){
output.write("CLIENT - "+message);
output.flush();
showMessage("\nCLIENT - "+message);
}
private void ClientRun() throws IOException{
String message="CLIENT HERE!";
sendMessage(message);
do{
try{
message=input.readLine();
showMessage("\n"+message);
}catch(EOFException eofException){
showMessage("\n Server ended the connection!");
}
}while(message!="EXIT");
}
(input and output are defined in GUI class in which this Client class is extended to. Defined as "protected BufferedReader input; protected PrintWriter output;")
Also, servers code:
public class ServerClass {
private ServerSocket server;
private Socket connection;
private BufferedReader input;
private BufferedWriter output;
public void startServer(){
try{
server=new ServerSocket(6789,100);
while(true){
try{
waitForConnection();
setStreams();
ServerRunning();
}catch(EOFException eofException){
showMessage("\n Server ended the connection!");
}finally{
close();
}
}
}catch(IOException ioException){
ioException.printStackTrace();
}
}
private void waitForConnection() throws IOException{
showMessage("Waiting for someone to connect... \n");
connection=server.accept();
showMessage("Now connected to "+ connection.getInetAddress().getHostName());
}
private void setStreams() throws IOException{
output = new BufferedWriter(new OutputStreamWriter(connection.getOutputStream()));
output.flush();
input= new BufferedReader(new InputStreamReader(connection.getInputStream()));
showMessage("\n Streams are now set. \n");
}
public void ServerRunning() throws IOException{
String message="SERVER HERE!";
sendMessage(message);
do{
try{
message=input.readLine();
showMessage("\n"+message);
}catch(EOFException eofException){
showMessage("\n Server ended the connection!");
}
}while(message!="EXIT");
}
private void close(){
showMessage("\n Closing connections... \n");
try{
output.close();
input.close();
connection.close();
}catch(IOException ioException){
ioException.printStackTrace();
}
}
private void showMessage(String text){
System.out.println(text);
}
private void sendMessage(String message){
try{
output.write("SERVER - "+message);
output.flush();
showMessage(message);
}catch(IOException ioException){
System.out.println("\n ERROR!");
}
}
Connection seems to be ok, so i don't get whats wrong. Any help would be appreciated.
PS: i also tried PrintWriter in server as well and also tried a try catch in stream statement, the problem remains.
You're using readLine() which expects a newline character. either add a \n to the messages you are sending or don't use readLine().
[SOLVED] As TedTrippin and Alfie mentioned readline(), messed my code. After adding "\n" in each message, everything seems to work smooth! I also changed printwriter to bufferwritter in client code, and i also added a try-catch function in sendMessage, cause printwritter seems to cause some problem as well for some reason. Anyway, everything is set and done! Thanks guys!
UPDATED CLIENT CODE:
private void ClientRun() throws IOException{
String message="CLIENT HERE! \n"; <----added \n here.
sendMessage(message);
do{
try{
message=input.readLine();
showMessage("\n"+message);
}catch(EOFException eofException){
showMessage("\n Server ended the connection!");
}
}while(message!="EXIT");
}
public void sendMessage(String message){
try{ <-----added try-catch statement
output.write("CLIENT - "+message+"\n"); <----adding "\n" here is super userful, instead of having to add \n in each message.
output.flush();
showMessage(message);
}catch(IOException ioException){
System.out.println("\n ERROR!");
}
}
protected BufferedReader input;
protected BufferedWriter output; <----changed printwriter to BufferWriter
UPDATED SERVER CODE:
public void ServerRunning() throws IOException{
String message="SERVER HERE! \n"; <--- added \n here as well.
sendMessage(message);
do{
try{
message=input.readLine();
showMessage("\n"+message);
}catch(EOFException eofException){
showMessage("\n Server ended the connection!");
}
}while(message!="EXIT");
}
Thanks guys!
After compairing this code with some I have written in the past using sockets , I noticed you are using output.write(string) and input.readline() - These do not mix well, readline() expects a newline and write does not give one.
Replace write() with println().
来源：https://stackoverflow.com/questions/43098904/java-sockets-server-client-communication