• 使用netty的第一个Hello World


    server端

    package com.netty.test;
    import io.netty.bootstrap.ServerBootstrap;
    import io.netty.channel.ChannelFuture;
    import io.netty.channel.ChannelInitializer;
    import io.netty.channel.ChannelOption;
    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 DiscardServer {

    private static int port = 8080;

    private static String tcpIp = "localhost";

    public static void run(){
    EventLoopGroup bossGroup = new NioEventLoopGroup();//用于处理服务器端,接收客户端链接
    EventLoopGroup workerGroup = new NioEventLoopGroup();//进行网络通信(读写)
    try {
    ServerBootstrap b = new ServerBootstrap();//辅助工具类,用于服务器通道的一系列配置
    //绑定两个线程组
    b.group(bossGroup, workerGroup)
    .channel(NioServerSocketChannel.class)//指定nio模式
    .childHandler(new ChannelInitializer<SocketChannel>() {//配置具体的数据处理方式,处理数据用io模式,该地方使用io包

    @Override
    protected void initChannel(SocketChannel socketChannel)
    throws Exception {
    socketChannel.pipeline().addLast(new ServerHandler());
    }

    }).option(ChannelOption.SO_BACKLOG, 128)//设置tcp缓冲区
    .option(ChannelOption.SO_SNDBUF, 32 * 1024) //设置发送数据缓冲区
    .option(ChannelOption.SO_RCVBUF, 32 * 1024)//设置接收数据的缓冲区
    .childOption(ChannelOption.SO_KEEPALIVE, true);//保持链接
    //绑定端口
    ChannelFuture future = b.bind(tcpIp, port).sync()/*b.bind(port).sync()*/;
    future.channel().closeFuture().sync();
    } catch (Exception e) {
    System.out.println("产生了异常;异常是" + e.getMessage());
    }finally{
    workerGroup.shutdownGracefully();
    bossGroup.shutdownGracefully();
    }

    }
    public static void main(String[] args) {
    run();
    }

    }

    ServerHandler类

    package com.netty.test;

    import io.netty.buffer.ByteBuf;
    import io.netty.buffer.Unpooled;
    import io.netty.channel.ChannelHandlerContext;
    import io.netty.channel.ChannelInboundHandlerAdapter;

    /*
    * 服务器接收和返回数据
    */
    public class ServerHandler extends ChannelInboundHandlerAdapter {

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {

    // 接收客户端的消息
    ByteBuf buf = (ByteBuf)msg;
    byte[] data = new byte[buf.readableBytes()];
    buf.readBytes(data);
    String request = new String(data, "utf-8");
    System.out.println("Server: " + request);
    // 写给客户端
    ctx.writeAndFlush(Unpooled.copiedBuffer("888".getBytes()));
    //.addListener(ChannelFutureListener.CLOSE);

    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
    cause.printStackTrace();
    ctx.close();
    }

    }

    Client端

    package com.netty.test;

    import io.netty.bootstrap.Bootstrap;
    import io.netty.buffer.Unpooled;
    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.NioSocketChannel;

    /*
    * 客户端
    */
    public class Client {

    private static int port = 8080;

    private static String tcpIp = "localhost";

    public static void main(String[] args) {
    EventLoopGroup worGroup = new NioEventLoopGroup();
    Bootstrap bootstrap = new Bootstrap();
    bootstrap.group(worGroup)
    .channel(NioSocketChannel.class)
    .handler(new ChannelInitializer<SocketChannel>() {

    @Override
    protected void initChannel(SocketChannel ch) throws Exception {
    ch.pipeline().addLast(new ClientHandler());

    }

    });
    try {
    ChannelFuture future = bootstrap.connect(tcpIp, port).sync();
    // 给服务器发送消息
    future.channel().writeAndFlush(Unpooled.copiedBuffer("Hello World!".getBytes()));
    future.channel().closeFuture().sync();
    } catch (InterruptedException e) {
    System.out.println("绑定ip和端口时抛出异常,异常是" + e.getMessage());
    e.printStackTrace();
    } finally {
    worGroup.shutdownGracefully();
    }


    }

    }

    ClientHandler类

    package com.netty.test;

    import io.netty.buffer.ByteBuf;
    import io.netty.channel.ChannelHandlerContext;
    import io.netty.channel.ChannelInboundHandlerAdapter;
    import io.netty.util.ReferenceCountUtil;
    /*
    * 接收服务器返回的消息
    */
    public class ClientHandler extends ChannelInboundHandlerAdapter{

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg)
    throws Exception {
    try {
    ByteBuf buf = (ByteBuf)msg;
    byte[] data = new byte[buf.readableBytes()];
    buf.readBytes(data);
    System.out.println("Client : " + new String(data).trim());
    } finally {
    ReferenceCountUtil.release(msg);
    }

    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
    throws Exception {
    cause.printStackTrace();
    ctx.close();
    }

    }

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  • 原文地址:https://www.cnblogs.com/wangjinyu/p/8616921.html
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