翻了翻《Netty 实战》,看了些概念,还是觉得似是而非,于是写了些代码,通道啥的都建得挺好。但是channelRead0一直收不到消息。
后来东摸西摸,发现我client 创建channel后马上发消息是不对的,此时channel还没有完全建好,导致服务端收不到消息。改成通道active后,server 给 client发送消息,client 收到消息后才开始向server发消息,此时sever是能收到的。
@Slf4j public class ChatServerHandler extends SimpleChannelInboundHandler<String> { public static ChannelGroup channels = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE); @Override public void handlerAdded(ChannelHandlerContext ctx) throws Exception { // 处理handler 添加,全局保存channel log.info("add a handler"); Channel incoming = ctx.channel(); for (Channel channel : channels) { channel.writeAndFlush("[SERVER] - " + incoming.remoteAddress() + " 加入/n"); } channels.add(ctx.channel()); } @Override public void handlerRemoved(ChannelHandlerContext ctx) throws Exception { // 处理handler 删除,全局删除channel Channel incoming = ctx.channel(); for (Channel channel : channels) { channel.writeAndFlush("[SERVER] - " + incoming.remoteAddress() + " 离开/n"); } channels.remove(ctx.channel()); } @Override protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception { Channel incoming = ctx.channel(); log.info("收到消息: " + msg); for (Channel channel : channels) { if (channel != incoming) { // 群发给其他用户 channel.writeAndFlush("[" + incoming.remoteAddress() + "]" + msg + "/n"); } else { // 回应当前用户 channel.writeAndFlush("[响应]" + msg + "/n"); } } } @Override public void channelActive(ChannelHandlerContext ctx) throws Exception { // 通道激活,通知client,可以准备通信了 Channel incoming = ctx.channel(); log.info("ChatClient:" + incoming.remoteAddress() + "在线"); incoming.writeAndFlush("welcome" + "/n"); } @Override public void channelInactive(ChannelHandlerContext ctx) throws Exception { // 通道失效,client 掉线 Channel incoming = ctx.channel(); log.info("ChatClient:" + incoming.remoteAddress() + "掉线"); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { Channel incoming = ctx.channel(); // 当出现异常就关闭连接 log.info("ChatClient:" + incoming.remoteAddress() + "异常"); cause.printStackTrace(); ctx.close(); } }
ServerBootstrap serverBootstrap = new ServerBootstrap(); NioEventLoopGroup bossGroup = new NioEventLoopGroup(); NioEventLoopGroup workerGroup = new NioEventLoopGroup(); serverBootstrap .group(bossGroup, workerGroup) .channel(NioServerSocketChannel.class) .childHandler( new ChannelInitializer<NioSocketChannel>() { @Override protected void initChannel(NioSocketChannel ch) throws Exception { ChannelPipeline pipeline = ch.pipeline(); pipeline.addLast("framer", new DelimiterBasedFrameDecoder(8192, Delimiters.lineDelimiter())); pipeline.addLast("decoder", new StringDecoder()); pipeline.addLast("encoder", new StringEncoder()); pipeline.addLast("handler", new ChatServerHandler()); log.info("ChatClient:" + ch.remoteAddress() + "连接上"); } } ).option(ChannelOption.SO_BACKLOG, 128) .childOption(ChannelOption.SO_KEEPALIVE, true) .bind(18169);
@Slf4j public class ChatClientHandler extends SimpleChannelInboundHandler<String> { @Override protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception { log.info(msg); Channel ch = ctx.channel(); // 收到welcome后,给server发送消息 if(msg.startsWith("welcome")){ ch.writeAndFlush("hello world!" + "/r/n"); ch.writeAndFlush("wish you happy!" + "/r/n"); } } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { cause.printStackTrace(); // 出现异常时关闭连接 ctx.close(); } }
Bootstrap bootstrap = new Bootstrap(); NioEventLoopGroup group = new NioEventLoopGroup(); bootstrap.group(group) .channel(NioSocketChannel.class) .handler( new ChannelInitializer<NioSocketChannel>() { @Override protected void initChannel(NioSocketChannel ch) throws Exception { ChannelPipeline pipeline = ch.pipeline(); // 解决粘包问题 pipeline.addLast("framer", new DelimiterBasedFrameDecoder(8192, Delimiters.lineDelimiter())); pipeline.addLast("decoder", new StringDecoder()); pipeline.addLast("encoder", new StringEncoder()); pipeline.addLast("handler", new ChatClientHandler()); // log.info("ChatServer:" + ch.remoteAddress() + "连接上"); } } ).option(ChannelOption.SO_KEEPALIVE, true); Channel channel = bootstrap.connect("127.0.0.1", 18169).channel(); }