Boostraping UDP Server for Netty 4.0?

Question

Can someone bootstrap me with a UDP Server for Netty 4.0? i see plenty of 3.x examples, but no sign of 4.x even at netty source example. (note I am very new to Netty )

Basically, it is the example at https://netty.io/Documentation/New+and+Noteworthy#HNewbootstrapAPI but for UDP instead. Help is much appreciated

Answer 1

Package netty-example includes classes QuoteOfTheMomentServer, QuoteOfTheMomentServerHandler, QuoteOfTheMomentClient and QuoteOfTheMomentClientHandler. These demonstrate how to create a simple UDP server.

I am pasting the code as it exists in Netty 4.1.24. I suggest to find these classes for the version of Netty that you are using.

QuoteOfTheMomentServer:

public final class QuoteOfTheMomentServer {

private static final int PORT = Integer.parseInt(System.getProperty("port", "7686"));

public static void main(String[] args) throws Exception {
    EventLoopGroup group = new NioEventLoopGroup();
    try {
        Bootstrap b = new Bootstrap();
        b.group(group)
         .channel(NioDatagramChannel.class)
         .option(ChannelOption.SO_BROADCAST, true)
         .handler(new QuoteOfTheMomentServerHandler());

        b.bind(PORT).sync().channel().closeFuture().await();
    } finally {
        group.shutdownGracefully();
    }
}
}

QuoteOfTheMomentServerHandler:

public class QuoteOfTheMomentServerHandler extends SimpleChannelInboundHandler<DatagramPacket> {

private static final Random random = new Random();

// Quotes from Mohandas K. Gandhi:
private static final String[] quotes = {
    "Where there is love there is life.",
    "First they ignore you, then they laugh at you, then they fight you, then you win.",
    "Be the change you want to see in the world.",
    "The weak can never forgive. Forgiveness is the attribute of the strong.",
};

private static String nextQuote() {
    int quoteId;
    synchronized (random) {
        quoteId = random.nextInt(quotes.length);
    }
    return quotes[quoteId];
}

@Override
public void channelRead0(ChannelHandlerContext ctx, DatagramPacket packet) throws Exception {
    System.err.println(packet);
    if ("QOTM?".equals(packet.content().toString(CharsetUtil.UTF_8))) {
        ctx.write(new DatagramPacket(
                Unpooled.copiedBuffer("QOTM: " + nextQuote(), CharsetUtil.UTF_8), packet.sender()));
    }
}

@Override
public void channelReadComplete(ChannelHandlerContext ctx) {
    ctx.flush();
}

@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
    cause.printStackTrace();
    // We don't close the channel because we can keep serving requests.
}
}