netty入门（一）

1.关于netty可以自行google，我先概述一下netty入门helloword  只要按步骤写 入门后就可自己专研源码

用maven构建：

        io.netty
        netty-all
        5.0.0.Alpha2

首先建立服务器端程序：

public class Mserver {
    public  static  void  main(String[] args) throws Exception{
        EventLoopGroup boss = new NioEventLoopGroup();
        EventLoopGroup worker = new NioEventLoopGroup();
        /**
         * 服务器端定义两个线程组 boss接收来自客服端信息然后转给worker处理
         */

        try {
            ServerBootstrap serverBootstrap = new ServerBootstrap();//辅助类建立通道
            serverBootstrap.group(boss,worker).channel(NioServerSocketChannel.class)
                    .childHandler(new MyserverInitializer());
            ChannelFuture channelFuture = serverBootstrap.bind(9999).sync();
            channelFuture.channel().closeFuture().sync();
        }finally {
            boss.shutdownGracefully();
            worker.shutdownGracefully();
        }


    }
}

在自定义handler类

public class MyServerHandler extends SimpleChannelInboundHandler {

    protected void messageReceived(ChannelHandlerContext channelHandlerContext, String s) throws Exception {
        System.out.println(channelHandlerContext.channel().remoteAddress()  +" news client to server" +s);//
        channelHandlerContext.writeAndFlush(" server to client" + new  Date());
    }

    /**
     *字符串s是client发给server的信息
     *channelHandlerContext.writeAndFlush（）获取通道然后发消息给client
     */
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        ctx.close();
    }
}

将handler绑定到pipline

public class MyserverInitializer extends ChannelInitializer {
    protected void initChannel(SocketChannel socketChannel) throws Exception {
        ChannelPipeline pipeline = socketChannel.pipeline();
        pipeline.addLast(new StringDecoder(CharsetUtil.UTF_8));
        pipeline.addLast(new StringEncoder(CharsetUtil.UTF_8));
        pipeline.addLast(new MyServerHandler());//绑定自定义handler类

    }

 

 

同理客户端类似的写三个类

public class MyClient {
    public  static  void  main(String[] args) throws Exception{

        EventLoopGroup eventLoopGroup = new NioEventLoopGroup();
        try {
            Bootstrap bootstrap = new Bootstrap();
            bootstrap.group(eventLoopGroup).channel(NioSocketChannel.class)
                    .handler(new netty_HelloWorld.MyClientInitializer());
            ChannelFuture channelFuture = bootstrap.bind("localhost",9999).sync();
            channelFuture.channel().closeFuture().sync();
        }finally {
            eventLoopGroup.shutdownGracefully();
        }


    }
}

public class MyClientHandler extends SimpleChannelInboundHandler {
    protected void messageReceived(ChannelHandlerContext channelHandlerContext, String s) throws Exception {
        System.out.println(channelHandlerContext.channel().remoteAddress()  +" news server to client" +s);//
        channelHandlerContext.writeAndFlush(" client to server " + UUID.randomUUID());

    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        ctx.writeAndFlush("来自客户端开启消息大门");
    }//只有重写这个类客户端才会开始想服务器端发送消息

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        ctx.close();
    }//抛出异常 必须重载
}

public class MyClientInitializer extends ChannelInitializer{


    protected void initChannel(SocketChannel socketChannel) throws Exception {
        ChannelPipeline pipeline = socketChannel.pipeline();
        pipeline.addLast(new StringDecoder(CharsetUtil.UTF_8));
        pipeline.addLast(new StringEncoder(CharsetUtil.UTF_8));
        pipeline.addLast(new MyClientHandler());//自定义handler放在最后
    }
}

建议边看边google查询先关关系，弄懂以上之后你就开始学习各种handler类了

之后查看源码看多线程机制

代码见github：https://github.com/anglesun/netty/tree/master