Re: in.close() closes out's socket -- is this a bug?
Duane Evenson wrote:
I have buffered input and output streams going to a socket. When I close
the input stream, it closes the socket without first flushing the output
buffer.
Should it do this? I would expect it to close the streams, but
leave the socket alone. The following code demonstrates this problem.
Invert the order of in.close() and out.close() and the program works.
Oh, I think I see.
Or rather, do you expect to be able to close input, but still use
output? If so...
Use shutdownInput(), not close(). This program below uses the same
order as you do, but in.close() is replaced by a call to
shutdownInput(). Now the client gets the write. (And my example
doesn't need telnet, just run it, you'll see both ends of the
connection. ;) Yes, this is one file -- note only one public class.
Just cut and paste into your IDE.
package fubar;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.logging.Level;
import java.util.logging.Logger;
public class TestFlush2 {
static final int PORT = 12345;
public static void main(String[] args)
{
new Thread( new TestFlushServer() ).start();
try
{
Thread.sleep(200); // wait a bit for server to come up
} catch (InterruptedException ex) { }
new Thread( new TestFlushClient() ).start();
}
}
class TestFlushServer implements Runnable {
public void run()
{
try
{
ServerSocket serverSocket =
new ServerSocket(TestFlush2.PORT);
Socket clientSocket = serverSocket.accept();
BufferedOutputStream out = new BufferedOutputStream(
clientSocket.getOutputStream());
BufferedReader in = new BufferedReader(
new InputStreamReader(
clientSocket.getInputStream()));
out.write("good output test string\n".getBytes("US-ASCII"));
// in.close();
clientSocket.shutdownInput();
if (clientSocket.isClosed())
{
System.out.println(
"clientSocket is closed by in.close");
}
out.close();
clientSocket.close();
serverSocket.close();
System.out.println("Server Done");
} catch (IOException ex)
{
Logger.getLogger(TestFlushServer.class.getName())
.log(Level.SEVERE, null, ex);
ex.printStackTrace();
}
}
}
class TestFlushClient implements Runnable
{
public void run()
{
try
{
Socket sock = new Socket("localhost", TestFlush2.PORT);
BufferedReader input = new BufferedReader(
new InputStreamReader(
sock.getInputStream(), "US-ASCII" ) );
String s;
while( (s = input.readLine()) != null )
{
System.out.println("CLIENT: "+s);
}
sock.close();
System.out.println("CLIENT: done");
} catch (UnknownHostException ex)
{
Logger.getLogger(TestFlushClient.class.getName())
.log(Level.SEVERE, null, ex);
} catch (IOException ex)
{
Logger.getLogger(TestFlushClient.class.getName())
.log(Level.SEVERE, null, ex);
}
}
}