Netty Socket编程

工程结构图

一、Socket服务端

1、创建MyServer 类

public class MyServer {
    public static void main(String[] args) throws  Exception{
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup worderGroup = new NioEventLoopGroup();
        try{

            ServerBootstrap serverBootstrap = new ServerBootstrap();
            serverBootstrap.group(bossGroup,worderGroup).channel(NioServerSocketChannel.class)
                    .childHandler(new MyServerinitializer());

            ChannelFuture channelFuture = serverBootstrap.bind(8899).sync();
            channelFuture.channel().closeFuture().sync();
        }finally {
            bossGroup.shutdownGracefully();
            worderGroup.shutdownGracefully();
        }
    }
}

　　

2、服务端处理器类MyServerHandle

public class MyServerHandle  extends SimpleChannelInboundHandler<String>{

    protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
        CommonUtil.println(ctx.channel().remoteAddress() + ", " + msg);
        ctx.channel().writeAndFlush("from server: " + UUID.randomUUID());
    }

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

　　当接收到请求后，向客户端写数据。

3、创建MyServerinitializer类

public class MyServerinitializer  extends ChannelInitializer<SocketChannel>{

    protected void initChannel(SocketChannel socketChannel) throws Exception {
        ChannelPipeline pipeline = socketChannel.pipeline();
        pipeline.addLast(new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE,0, 4, 0, 4));
        pipeline.addLast(new LengthFieldPrepender(4));
        pipeline.addLast(new StringDecoder(CharsetUtil.UTF_8));
        pipeline.addLast(new StringEncoder(CharsetUtil.UTF_8));
        pipeline.addLast(new MyServerHandle());
    }
}

　　

二、客户端

1、MyClient 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 MyClientInitializer());

            ChannelFuture channelFuture = bootstrap.connect("localhost",8899).sync();
            channelFuture.channel().closeFuture().sync();
        }finally {
            eventLoopGroup.shutdownGracefully();
        }
    }
}

　　

2、客户端处理器MyClientHandle

public class MyClientHandle extends SimpleChannelInboundHandler<String> {

    //服务端向客户端发送消息时，该方法会被调用
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
        CommonUtil.println(ctx.channel().remoteAddress());
        CommonUtil.println("client output:" + msg);
        ctx.writeAndFlush("from client: " + LocalDateTime.now());
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        ctx.writeAndFlush("来自客户端的消息");
    }

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

　　客户端channel active后，向服务端发送消息

3、MyClientInitializer类

public class MyClientInitializer  extends ChannelInitializer<SocketChannel> {

    protected void initChannel(SocketChannel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();
        pipeline.addLast(new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE,0, 4, 0, 4));
        pipeline.addLast(new LengthFieldPrepender(4));
        pipeline.addLast(new StringDecoder(CharsetUtil.UTF_8));
        pipeline.addLast(new StringEncoder(CharsetUtil.UTF_8));
        pipeline.addLast(new MyClientHandle());
    }
}

　　

三、测试

1、启动服务端

2、启动客户端（可以启动多个）

服务端输出结果

客户端1输出

客户端2输出