I've got a server/client program that I am writing in which a server sends messages to a client and vise versa. It works perfectly, except for the out.println
statements in the printRemoteAddress()
method. "HELLO1"
and "HELLO2"
print to the client, but "HELLO3
" does not.
My question is, why does "HELLO3"
not print to the client, but the first two do?
SERVER CODE:
class Worker extends Thread {
Socket sock;
Worker (Socket s) {sock = s;}
public void run() {
PrintStream out = null;
BufferedReader in = null;
try {
in = new BufferedReader(new InputStreamReader(sock.getInputStream()));
out = new PrintStream(sock.getOutputStream());
try {
String name;
name = in.readLine();
System.out.println("Looking up " + name);
printRemoteAddress(name, out);
} catch (IOException x) {
System.out.println("Server read error");
x.printStackTrace();
}
sock.close();
} catch (IOException ioe) {System.out.println(ioe);}
}
static void printRemoteAddress (String name, PrintStream out) {
try {
out.println("HELLO1");
out.println("HELLO2");
out.println("HELLO3");
InetAddress machine = InetAddress.getByName(name);
} catch(UnknownHostException ex) {
out.println ("Failed in attempt to look up " + name);
}
}
public class InetServer {
public static void main(String a[]) throws IOException {
int q_len = 6;
int port = 2000;
Socket sock;
ServerSocket servsock = new ServerSocket(port, q_len);
System.out.println
("Inet server 1.8 starting up, listening at port 2000.\n");
while (true) {
sock = servsock.accept();
new Worker(sock).start();
}
}
CLIENT CODE:
public class InetClient {
public static void main (String args[]) {
String serverName;
if (args.length < 1) serverName = "localhost";
else serverName = args[0];
System.out.println("Inet Client, 1.0.\n");
System.out.println("Using server: " + serverName + ", Port: 2000");
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
try {
String name;
do {
System.out.print("Enter hostname of IP address: ");
System.out.flush();
name = in.readLine();
if (name.indexOf("stop") < 0)
getRemoteAddress(name, serverName);
} while (name.indexOf("stop") < 0);
System.out.println("Process stopped.");;
} catch (IOException x) {x.printStackTrace();}
}
static void getRemoteAddress (String name, String serverName) {
Socket sock;
BufferedReader fromServer;
PrintStream toServer;
String textFromServer;
try {
sock = new Socket(serverName, 2000);
fromServer = new BufferedReader (new InputStreamReader(sock.getInputStream()));
toServer = new PrintStream(sock.getOutputStream());
toServer.println(name);
toServer.flush();
for (int i = 1; i <3; i++) {
textFromServer = fromServer.readLine();
if (textFromServer != null) System.out.println(textFromServer);
}
sock.close();
} catch (IOException x) {
System.out.println("Socket error.");
x.printStackTrace();
}
}
}
for (int i = 1; i <3; i++) {
Bzzzzzzzzt. This iterates twice, not three times. It should be
for (int i = 1; i <= 3; i++) {
In fact it would make more sense not to hardwire the 3 in at all:
while ((textFromServer = fromServer.readLine()) != null {
System.out.println(textFromServer);
}
The println()
isn't 'skipped', but PrintStream
is buffered and doesn't auto-flush on newlines. You can construct it with a second parameter so as to do that, or call flush()
as appropriate, or use a PrintWriter
.
You should also close the PrintStream/PrintWriter
, not the Socket
.