Netty的入门-UDP协议开发

来源：互联网发布：多线程实例 java 编辑：程序博客网时间：2024/06/05 01:02

User Datagram Protocal直接用IP协议进行数据发送，提供的是面向无连接，不可靠的数据投递服务。使用UDP的应用程序必须自己解决数据丢失，重复，排序，差错确认等问题。UDP数据包的格式如下：

UDP协议的特点：

1、无连接，在数据传输前，发送方和接收方互换信息使双方同步

2、UDP对接收到的数据不发确认信号

3、UDP传输数据比TCP快，系统开销也小，常用于可靠性要求不高的数据传输，如视频语音图片以及简单文件传输

public class ChineseProverbServer {public static void main(String[] args) {int port = 8089;EventLoopGroup group = new NioEventLoopGroup();try {Bootstrap b = new Bootstrap();b.group(group).channel(NioDatagramChannel.class).option(ChannelOption.SO_BROADCAST, true).handler(new ChineseProverbServerHandler());b.bind(port).sync().channel().closeFuture().await();} catch (Exception e) {e.printStackTrace();} finally {group.shutdownGracefully();}}static class ChineseProverbServerHandler extends SimpleChannelInboundHandler<DatagramPacket> {private static final String[] DICTIONARY = {"只要功夫深铁杵磨成针", "旧时王谢堂前燕飞入寻常百姓家", "洛阳亲友如相问一片冰心在玉壶", "一寸光阴一寸金寸金难买寸光阴", "老骥伏枥志在千里"};private String nextQuote() {int quoteId = ThreadLocalRandom.current().nextInt(DICTIONARY.length);return DICTIONARY[quoteId];}@Overrideprotected void channelRead0(ChannelHandlerContext ctx,DatagramPacket msg) throws Exception {String request = msg.content().toString(CharsetUtil.UTF_8);System.out.println(request);if ("谚语字典查询".equals(request)) {ctx.writeAndFlush(new DatagramPacket(Unpooled.copiedBuffer("谚语字典查询结果：" + nextQuote(), CharsetUtil.UTF_8), msg.sender()));}}@Overridepublic void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)throws Exception {ctx.close();cause.printStackTrace();}}}

public class ChineseProverbClient {public static void main(String[] args) {EventLoopGroup group = new NioEventLoopGroup();try {Bootstrap b = new Bootstrap();b.group(group).channel(NioDatagramChannel.class).option(ChannelOption.SO_BROADCAST, true).handler(new ChineseProverbClientHandlert());Channel ch = b.bind(0).sync().channel();ch.writeAndFlush(new DatagramPacket(Unpooled.copiedBuffer("谚语字典查询", CharsetUtil.UTF_8), new InetSocketAddress("localhost", 8089)));if (!ch.closeFuture().await(15000)) {System.out.println("查询超时！");}} catch (Exception e) {e.printStackTrace();} finally {group.shutdownGracefully();}}static class ChineseProverbClientHandlert extends SimpleChannelInboundHandler<DatagramPacket> {@Overrideprotected void channelRead0(ChannelHandlerContext ctx,DatagramPacket msg) throws Exception {String response = msg.content().toString(CharsetUtil.UTF_8);if (response.startsWith("谚语字典查询结果：")) {System.out.println(response);ctx.close();}}}}

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