[转]Netty入门(最简单的Netty客户端/服务器程序)

 1 package com.gerry.netty.server; 2 ?3 import io.netty.bootstrap.ServerBootstrap; 4 import io.netty.channel.ChannelFuture; 5 import io.netty.channel.ChannelInitializer; 6 import io.netty.channel.EventLoopGroup; 7 import io.netty.channel.nio.NioEventLoopGroup; 8 import io.netty.channel.socket.SocketChannel; 9 import io.netty.channel.socket.nio.NioServerSocketChannel;10 11 public class EchoServer {12 ????private final int port;13 14 ????public EchoServer(int port) {15 ????????this.port = port;16 ????}17 18 ????public void start() throws Exception {19 ????????EventLoopGroup group = new NioEventLoopGroup();20 ????????try {21 ????????????ServerBootstrap sb = new ServerBootstrap();22 ????????????sb.group(group) // 绑定线程池23 ????????????????????.channel(NioServerSocketChannel.class) // 指定使用的channel24 ????????????????????.localAddress(this.port)// 绑定监听端口25 ????????????????????.childHandler(new ChannelInitializer<SocketChannel>() { // 绑定客户端连接时候触发操作26 27 ????????????????????????????????@Override28 ????????????????????????????????protected void initChannel(SocketChannel ch) throws Exception {29 ????????????????????????????????????System.out.println("connected...; Client:" + ch.remoteAddress());30 ????????????????????????????????????ch.pipeline().addLast(new EchoServerHandler()); // 客户端触发操作31 ????????????????????????????????}32 ????????????????????????????});33 ????????????ChannelFuture cf = sb.bind().sync(); // 服务器异步创建绑定34 ????????????System.out.println(EchoServer.class + " started and listen on " + cf.channel().localAddress());35 ????????????cf.channel().closeFuture().sync(); // 关闭服务器通道36 ????????} finally {37 ????????????group.shutdownGracefully().sync(); // 释放线程池资源38 ????????}39 ????}40 41 ????public static void main(String[] args) throws Exception {42 ????????new EchoServer(65535).start(); // 启动43 ????}44 }

 1 package com.gerry.netty.server; 2 ?3 import io.netty.buffer.Unpooled; 4 import io.netty.channel.ChannelFutureListener; 5 import io.netty.channel.ChannelHandlerContext; 6 import io.netty.channel.ChannelInboundHandlerAdapter; 7 ?8 public class EchoServerHandler extends ChannelInboundHandlerAdapter { 9 ????@Override10 ????public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {11 ????????System.out.println("server channelRead...; received:" + msg);12 ????????ctx.write(msg);13 ????}14 15 ????@Override16 ????public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {17 ????????System.out.println("server channelReadComplete..");18 ????????// 第一种方法：写一个空的buf，并刷新写出区域。完成后关闭sock channel连接。19 ????????ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(ChannelFutureListener.CLOSE);20 ????????//ctx.flush(); // 第二种方法：在client端关闭channel连接，这样的话，会触发两次channelReadComplete方法。21 ????????//ctx.flush().close().sync(); // 第三种：改成这种写法也可以，但是这中写法，没有第一种方法的好。22 ????}23 24 ????@Override25 ????public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {26 ????????System.out.println("server occur exception:" + cause.getMessage());27 ????????cause.printStackTrace();28 ????????ctx.close(); // 关闭发生异常的连接29 ????}30 }

 1 package com.gerry.netty.client; 2 ?3 import io.netty.bootstrap.Bootstrap; 4 import io.netty.channel.ChannelFuture; 5 import io.netty.channel.ChannelInitializer; 6 import io.netty.channel.EventLoopGroup; 7 import io.netty.channel.nio.NioEventLoopGroup; 8 import io.netty.channel.socket.SocketChannel; 9 import io.netty.channel.socket.nio.NioSocketChannel;10 11 import java.net.InetSocketAddress;12 13 public class EchoClient {14 ????private final String host;15 ????private final int port;16 17 ????public EchoClient() {18 ????????this(0);19 ????}20 21 ????public EchoClient(int port) {22 ????????this("localhost", port);23 ????}24 25 ????public EchoClient(String host, int port) {26 ????????this.host = host;27 ????????this.port = port;28 ????}29 30 ????public void start() throws Exception {31 ????????EventLoopGroup group = new NioEventLoopGroup();32 ????????try {33 ????????????Bootstrap b = new Bootstrap();34 ????????????b.group(group) // 注册线程池35 ????????????????????.channel(NioSocketChannel.class) // 使用NioSocketChannel来作为连接用的channel类36 ????????????????????.remoteAddress(new InetSocketAddress(this.host, this.port)) // 绑定连接端口和host信息37 ????????????????????.handler(new ChannelInitializer<SocketChannel>() { // 绑定连接初始化器38 ????????????????????????????????@Override39 ????????????????????????????????protected void initChannel(SocketChannel ch) throws Exception {40 ????????????????????????????????????System.out.println("connected...");41 ????????????????????????????????????ch.pipeline().addLast(new EchoClientHandler());42 ????????????????????????????????}43 ????????????????????????????});44 ????????????System.out.println("created..");45 46 ????????????ChannelFuture cf = b.connect().sync(); // 异步连接服务器47 ????????????System.out.println("connected..."); // 连接完成48 49 ????????????cf.channel().closeFuture().sync(); // 异步等待关闭连接channel50 ????????????System.out.println("closed.."); // 关闭完成51 ????????} finally {52 ????????????group.shutdownGracefully().sync(); // 释放线程池资源53 ????????}54 ????}55 56 ????public static void main(String[] args) throws Exception {57 ????????new EchoClient("127.0.0.1", 65535).start(); // 连接127.0.0.1/65535，并启动58 ????}59 }

 1 package com.gerry.netty.client; 2 ?3 import java.nio.charset.Charset; 4 ?5 import io.netty.buffer.ByteBuf; 6 import io.netty.buffer.ByteBufUtil; 7 import io.netty.buffer.Unpooled; 8 import io.netty.channel.ChannelHandlerContext; 9 import io.netty.channel.SimpleChannelInboundHandler;10 import io.netty.util.CharsetUtil;11 12 public class EchoClientHandler extends SimpleChannelInboundHandler<ByteBuf> {13 14 ????@Override15 ????public void channelActive(ChannelHandlerContext ctx) throws Exception {16 ????????System.out.println("client channelActive..");17 ????????ctx.writeAndFlush(Unpooled.copiedBuffer("Netty rocks!", CharsetUtil.UTF_8)); // 必须有flush18 19 ????????// 必须存在flush20 ????????// ctx.write(Unpooled.copiedBuffer("Netty rocks!", CharsetUtil.UTF_8));21 ????????// ctx.flush();22 ????}23 24 ????@Override25 ????protected void channelRead0(ChannelHandlerContext ctx, ByteBuf msg) throws Exception {26 ????????System.out.println("client channelRead..");27 ????????ByteBuf buf = msg.readBytes(msg.readableBytes());28 ????????System.out.println("Client received:" + ByteBufUtil.hexDump(buf) + "; The value is:" + buf.toString(Charset.forName("utf-8")));29 ????????//ctx.channel().close().sync();// client关闭channel连接30 ????}31 32 ????@Override33 ????public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {34 ????????cause.printStackTrace();35 ????????ctx.close();36 ????}37 38 }