2.netty的helloworld

一.server

1.server

package netty.helloworld;import java.net.InetSocketAddress;import io.netty.bootstrap.ServerBootstrap;import io.netty.channel.ChannelFuture;import io.netty.channel.ChannelInitializer;import io.netty.channel.EventLoopGroup;import io.netty.channel.nio.NioEventLoopGroup;import io.netty.channel.socket.SocketChannel;import io.netty.channel.socket.nio.NioServerSocketChannel;public class netty_server {public static void main(String [] args){new netty_server().start();}public void start(){//1.引导辅助程序ServerBootstrap boot = new ServerBootstrap();//2.创建EventLoop用于处理Channel的所有请求所有数据逻辑处理EventLoopGroup group = new NioEventLoopGroup();try {boot.group(group);//3.设置Channel类型为Nio类型boot.channel(NioServerSocketChannel.class);//4.设置监听端口boot.localAddress(new InetSocketAddress(9090));//5.每当连接达到时就创建一个Channel实现类(传入一个ChannelInitializer接口)boot.childHandler(new ChannelInitializer<SocketChannel>(){@Overrideprotected void initChannel(SocketChannel channel) throws Exception {//pipeline管理channel中的Handler，在channel队列中添加一个handler来处理业务channel.pipeline().addLast("myHandler", new netty_server_handler());}});//6.配置完成,绑定server,通过调用sync同步方法阻塞直到绑定成功,同时返回一个回调ChannelFuture future  = boot.bind().sync();System.out.println("启动server :"+ netty_server.class.getName());System.out.println("监听的端口是 :"+ future.channel().localAddress());//7.程序会一直等待直到channel关闭future.channel().closeFuture().sync();} catch (Exception e) {e.printStackTrace();}}}

2.handler

package netty.helloworld;import io.netty.channel.ChannelInboundHandlerAdapter;import io.netty.buffer.ByteBuf;import io.netty.buffer.Unpooled;import io.netty.channel.ChannelFutureListener;import io.netty.channel.ChannelHandler.Sharable;import io.netty.channel.ChannelHandlerContext;/* * 这个类是我们的具体业务类: *  * 1.处理接收到的数据,方法中写处理逻辑 *  * 2.注解@Sharable(这个类对象)可以让它在channels间共享 *  * 3. * channelRead:拿到接收到的数据 * channelReadComplete：在channelRead之后执行,这里添加监听器关闭channel *  *  */@Sharablepublic class netty_server_handler extends ChannelInboundHandlerAdapter {@Overridepublic void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {//通过ByteBuf读取收到的客户端消息,打印        ByteBuf result = (ByteBuf) msg;          byte[] result1 = new byte[result.readableBytes()];          result.readBytes(result1);          String resultStr = new String(result1);          System.out.println("Client said:" + resultStr);          result.release();        ctx.write(msg);//写回数据}@Overridepublic void channelReadComplete(ChannelHandlerContext ctx) throws Exception {//flush掉所有写回的数据//当flush完成后关闭channelctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(ChannelFutureListener.CLOSE); }@Overridepublic void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {ctx.close();//出现异常时关闭channel}}

二.client

1.client

package netty.helloworld;import java.net.InetSocketAddress;import io.netty.bootstrap.Bootstrap;import io.netty.channel.ChannelFuture;import io.netty.channel.ChannelFutureListener;import io.netty.channel.ChannelHandler;import io.netty.channel.ChannelInitializer;import io.netty.channel.EventLoopGroup;import io.netty.channel.nio.NioEventLoopGroup;import io.netty.channel.socket.SocketChannel;import io.netty.channel.socket.nio.NioSocketChannel;public class netty_client {public static void main(String[] args) throws InterruptedException {new netty_client().start();}public void start() throws InterruptedException{//1.创建EventLoop：一个线程驱动，处理一个channel 所有 IO事件EventLoopGroup group = new NioEventLoopGroup(); try {//2.创建引导Bootstrap b = new Bootstrap();b.group(group);b.channel(NioSocketChannel.class);//设置channel为Nio类型b.remoteAddress(new InetSocketAddress("192.168.31.170", 9090));//服务器ip和port//3.创建handler(客户端处理者)传入一个ChannelInitializer接口b.handler(new ChannelInitializer<SocketChannel>() {public void initChannel(SocketChannel ch) throws Exception {ch.pipeline().addLast( new netty_client_handler());}});//4.ChannelFuture f = b.connect().sync();f.addListener(new ChannelFutureListener() {public void operationComplete(ChannelFuture future) throws Exception {if(future.isSuccess()){System.out.println("client connected");}else{System.out.println("server attemp failed");future.cause().printStackTrace();}}});//5.f.channel().closeFuture().sync();}catch (Exception e){}finally{group.shutdownGracefully().sync();}}}

2.handler

package netty.helloworld;import io.netty.buffer.ByteBuf;import io.netty.channel.ChannelHandlerContext;import io.netty.channel.SimpleChannelInboundHandler;public class netty_client_handler extends SimpleChannelInboundHandler<ByteBuf >{@Overrideprotected void messageReceived(ChannelHandlerContext arg0, ByteBuf arg1) throws Exception {}@Override//此方法会在连接到服务器后被调用,在这里向服务器发送消息public void channelActive(ChannelHandlerContext ctx) throws Exception {        String msg = "Are you ok?";          ByteBuf encoded = ctx.alloc().buffer(4 * msg.length());          encoded.writeBytes(msg.getBytes());          ctx.write(encoded);          ctx.flush(); }@Overridepublic void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {}}