CODEWITHSUNDEEP
javanetwork-programmingnetty
idiotprogrammer
idiotprogrammer

Reputation: 146

Netty WriteAndFlush method doesnt work

Behold The following code:

public final class SecureChatClient {

static final String HOST = System.getProperty("host", "127.0.0.1");
static final int PORT = Integer.parseInt(System.getProperty("port", "8992"));

public static void main(String[] args) throws Exception {
    // Configure SSL.
    final SslContext sslCtx = SslContext.newClientContext(InsecureTrustManagerFactory.INSTANCE);

    EventLoopGroup group = new NioEventLoopGroup();
    try {
        Bootstrap b = new Bootstrap();
        b.group(group)
         .channel(NioSocketChannel.class)
         .handler(new NetworkInitializer(sslCtx));

        // Start the connection attempt.
        Channel ch = b.connect(HOST, PORT).sync().channel();

        // Read commands from the stdin.
        ChannelFuture lastWriteFuture = null;
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        //does not work
        ch.writeAndFlush("hi");
        while (true) {
            String line = in.readLine();
         if (line == null) {
            break;
            //(goes to if writefuture !=null)
            }

            // Sends the received line to the server.
            lastWriteFuture = ch.writeAndFlush(line + "\r\n");

        }

        // Wait until all messages are flushed before closing the channel.
        if (lastWriteFuture != null) {
            lastWriteFuture.sync();
        }
    } finally {
        // The connection is closed automatically on shutdown.
        group.shutdownGracefully();
    }
}}

That code was modified from netty's SecureChatClient Class http://netty.io/wiki/user-guide-for-4.x.html with the added in line

            ch.writeAndFlush("hi");

before the while loop. The output on the server does not read that line. I can't understand why that is, and to me it almost seems like the ch.writeandflush method itself doesn't work outside of a loop.

If im not supposed to use ch.writeandlfush outside of a loop, is there any better way to send a message to a server on startup?

Solution: all writeandflush statements must end with "\r\n" in order to flush. With out that they dont flush. I don't understand why that is but whatever.

Code solution: ch.writeAndFlush("hi\r\n");

Upvotes: 2

Views: 6657

Answers (2)

idiotprogrammer
idiotprogrammer

Reputation: 146

Solution: all writeandflush statements must end with "\r\n" in order to flush. With out that they dont flush. I don't understand why that is but whatever.

Code solution: ch.writeAndFlush("hi\r\n");

Upvotes: 3

Norman Maurer
Norman Maurer

Reputation: 23557

You should check what the ChannelFuture that is returned by writeAndFlush(...) tells you. I bet you get some sort of exception.

Upvotes: 3

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