Java Socket why server can not reply client

Question

I wanna write the code to let Client send a string to Server, Server print the string and reply a string, then Client print the string Server reply.
My Server

public class Server {

public static void main(String[] args) throws IOException {
    ServerSocket ss = null;
    Socket s = null;
    try {
        ss = new ServerSocket(34000);
        s = ss.accept();
        BufferedReader in = new BufferedReader(new InputStreamReader(
                s.getInputStream()));
        OutputStreamWriter out = new OutputStreamWriter(s.getOutputStream());

        while (true) {
            String string = in.readLine();
            if (string != null) {
                System.out.println("br: " + string);

                if (string.equals("end")) {
                    out.write("to end");
                    out.flush();
                    out.close();
                    System.out.println("end");
                    // break;
                }
            }
        }
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        s.close();
        ss.close();
    }
}
}

My Client:

public class Client {
public static void main(String[] args) {
    Socket socket =null;


    try {
        socket = new Socket("localhost", 34000);
        BufferedReader in =new BufferedReader(new InputStreamReader(socket.getInputStream()));
        OutputStreamWriter out = new OutputStreamWriter(socket.getOutputStream());

        String string = "";
        string = "end";
        out.write(string);
        out.flush();
        while(true){
            String string2 = in.readLine();
            if(string2.equals("to end")){
                System.out.println("yes sir");
                break;
            }
        }


    }  catch (Exception e) {
        e.printStackTrace();
    }finally{
        try {
            System.out.println("closed client");
            socket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}
}

are there some somethings wrong? if i remove the code "while(true) ..." in client class, it's OK.

"public String readLine() Reads a line of text. A line is considered to be terminated by any one of a line feed ('\n'), a carriage return ('\r'), or a carriage return followed immediately by a linefeed." -> docs.oracle.com/javase/7/docs/api/java/io/… — Fildor
– Fildor, Commented Oct 21, 2013 at 8:24
When your server is reading newline in.readLine(), you can use the following in client: PrintWriter out = new PrintWriter(socket.getOutputStream(), true); out.println(string); — bprasanna
– bprasanna, Commented Oct 21, 2013 at 8:28
Your code is wrong. If readLine() returns null you must close the socket and exit the loop. — user207421
– user207421, Commented Oct 21, 2013 at 8:46

Arun Chandran Chackachattil · Accepted Answer · 2013-10-21 14:01:07Z

4

you should add "\r\n" at the end of the String which write into stream.

example:

client :

    string = "end";
    out.write(string + "\r\n");
    out.flush();

server :

    out.write("to end" + "\r\n");
    out.flush();
    out.close();
    System.out.println("end");
                // break;

edited Oct 21, 2013 at 14:01

Arun Chandran Chackachattil

3,3627 gold badges33 silver badges45 bronze badges

answered Oct 21, 2013 at 8:53

shadow

947 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

shadow Over a year ago

I try, and it work well in ecplise.Can you tell me what is your IDE and what kind of OS

Hossein Kurd Over a year ago

It doesn't work in mt case: stackoverflow.com/questions/63127834

Pignic · Accepted Answer · 2013-10-21 08:35:03Z

0

I don't see the server response. You do a

System.out.println("br: " + string);

but not a

out.write(string);
out.flush();

answered Oct 21, 2013 at 8:35

Pignic

4983 silver badges12 bronze badges

Comments

Debabrata · Accepted Answer · 2013-10-21 09:05:02Z

0

Appand "\n" to end of the response from server.

outToClient.writeBytes(sb.toString() + "\n");

answered Oct 21, 2013 at 9:05

Debabrata

52 bronze badges

Comments

user207421 · Accepted Answer · 2013-10-21 09:11:52Z

0

You are reading lines but you aren't writing lines. Add a newline, or call BufferedReader.newLine().

answered Oct 21, 2013 at 9:11

user207421

312k45 gold badges324 silver badges493 bronze badges

Collectives™ on Stack Overflow

Java Socket why server can not reply client

4 Answers 4

2 Comments

Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

2 Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related