TsanChung wrote:

> I want to make a java TCP socket client to communicate with a TCP
> server socket on linux.
> Are there some sample C unix server and java client socket programs
> available?
>
> The Richard Stevens' "Unix network programming" book described a TCP
> server (tcpcliserv04.c) and client (tcpcli04.c). I compiled and
> executed them successfully as follows:
>
> $ tcpcliserv04 &
> $ tcpcli04 172.20.11.211
[snip]
>
> $ java socketClientWriteRead 172.20.11.66

Did you mean to connect to a different server with the Java client?

The error below means that the server refused the connection, usually because
there is nothing listening on the requested port.

> Exception in thread "main" java.net.ConnectException: Connection
> refused
> at java.net.PlainSocketImpl.socketConnect(Native Method)
> at java.net.PlainSocketImpl.doConnect(PlainSocketImpl .java:
> 333)
> at
> java.net.PlainSocketImpl.connectToAddress(PlainSoc ketImpl.java:195)
> at java.net.PlainSocketImpl.connect(PlainSocketImpl.j ava:182)
> at java.net.SocksSocketImpl.connect(SocksSocketImpl.j ava:366)
> at java.net.Socket.connect(Socket.java:518)
> at java.net.Socket.connect(Socket.java:468)
> at java.net.Socket.(Socket.java:365)
> at java.net.Socket.(Socket.java:179)
> at socketClientWriteRead.main(socketClientWriteRead.j ava:18)

--
Nigel Wade

On Oct 10, 7:51*pm, TsanChung wrote:
> I want to make a java TCP socket client to communicate with a TCP
> server socket on linux.
> Are there some sample C unix server and java client socket programs
> available?
>
> The Richard Stevens' "Unix network programming" book described a TCP
> server (tcpcliserv04.c) and client (tcpcli04.c). *I compiled and
> executed them successfully as follows:
>
> $ tcpcliserv04 &
> $ tcpcli04 *172.20.11.211
> 12
> 12
> 90
> 90
>
> I start to write a java socket client program but it fail to connect.
> Please help.
> Thanks.
>
> import java.net.*;
> import java.io.*;
>
> public class socketClientWriteRead
> {
> * *public static final int PORT = 9877;
>
> * *public static void main(String[] args) throws IOException
> * *{
> * * * * *String host = "";
> * * * * *if (args.length >= 1)
> * * * * * * *host = args[0];
> * * * * * * *//String host = args[0];
> * * * * *byte[] bytes = new byte[1024];
> * * * * *int len = 0;
> * * * *int ch = 0;
> * * * * *Socket sock = new Socket(host, PORT);
> * * * * *InputStream in = sock.getInputStream();
> * * * * *OutputStream out = sock.getOutputStream();
> * * * *System.out.println( "Hello World!" );
>
> * * * * *while (len > 0 || ch != -1) {
> * * * * * * if ((len = in.read(bytes)) > 0)
> * * * * * * * *System.out.write(bytes, 0, len);
>
> * * * * * if ((ch = System.in.read()) != -1)
> * * * * * * *out.write(ch);
> * * * * *} // while
> * * * * *in.close();
> * * * *out.close();
> * * }
>
> }
>
> $ java socketClientWriteRead 172.20.11.66
> Exception in thread "main" java.net.ConnectException: Connection
> refused
> * * * * at java.net.PlainSocketImpl.socketConnect(Native Method)
> * * * * at java.net.PlainSocketImpl.doConnect(PlainSocketImpl .java:
> 333)
> * * * * at
> java.net.PlainSocketImpl.connectToAddress(PlainSoc ketImpl.java:195)
> * * * * at java.net.PlainSocketImpl.connect(PlainSocketImpl.j ava:182)
> * * * * at java.net.SocksSocketImpl.connect(SocksSocketImpl.j ava:366)
> * * * * at java.net.Socket.connect(Socket.java:518)
> * * * * at java.net.Socket.connect(Socket.java:468)
> * * * * at java.net.Socket.(Socket.java:365)
> * * * * at java.net.Socket.(Socket.java:179)
> * * * * at socketClientWriteRead.main(socketClientWriteRead.j ava:18)


On which port your server is listening ?
On which port your client is trying to connect to server ?

On 10 Oct 2008 at 14:51, TsanChung wrote:
> $ tcpcliserv04 &
[snip]
> I start to write a java socket client program but it fail to connect.

Your client program seems fine (it's working OK here at least) - as long
as the server (actually called tcpserv04 in the books's provided source
code?) is still alive then you shouldn't have any problem connecting.