(二)第二个netty程序(使用netty的websocket)

先创建server

public class MyServer {

    public static void main(String[] args) throws InterruptedException {
        EventLoopGroup bossGroup=new NioEventLoopGroup();
        EventLoopGroup workerGroup=new NioEventLoopGroup();
     try {

         ServerBootstrap serverBootstrap =new ServerBootstrap();

         serverBootstrap.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class)
                 .childHandler(new MyServerInitializer());
         ChannelFuture channelFuture = serverBootstrap.bind(8899).sync();

         channelFuture.channel().closeFuture().sync();

     }finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
     }

    }

}

 * @Description:    客户端一旦跟服务端连接之后这个对象创建,  initChannel方法得到调用
 */
public class MyServerInitializer extends ChannelInitializer<SocketChannel> {


    @Override
    protected void initChannel(SocketChannel ch) throws Exception {

        ChannelPipeline pipeline = ch.pipeline();
                            //解码器
        pipeline.addLast(new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE,0,4,0,4));
                                //编码器
        pipeline.addLast(new LengthFieldPrepender(4));

        pipeline.addLast(new StringDecoder(CharsetUtil.UTF_8));
        pipeline.addLast(new StringEncoder(CharsetUtil.UTF_8));

        pipeline.addLast(new MyServerHandler());

    }
}

public class MyServerHandler extends SimpleChannelInboundHandler<String> {

    /**
     * @Description //TODO
     * @Param [ctx, msg] ctx: netty上下文信息,  msg:客户端真正接受过来的对象
     * @return void
     **/
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
        System.out.println( ctx.channel().remoteAddress()+","+msg);
        ctx.channel().writeAndFlush("from server:"+ UUID.randomUUID());   //write()和flush()方法的简写

    }

    /**
     * @Description //如果出现异常怎样处理
     * @Param [ctx, cause]
     * @return void
     **/
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        super.exceptionCaught(ctx, cause);
        ctx.close();
    }
}

再创建client 过程于server端类似 不同点在1.传入channel的时候是NioSocketChannel.class
2.传入handler而不是server端传的childHandler

  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();
        }

    }

public class MyClientInitializer extends ChannelInitializer<SocketChannel> {
    @Override
    protected void initChannel(SocketChannel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();
        //解码器
        pipeline.addLast(new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE,0,4,0,4));
        //编码器
        pipeline.addLast(new LengthFieldPrepender(4));

        pipeline.addLast(new StringDecoder(CharsetUtil.UTF_8));
        pipeline.addLast(new StringEncoder(CharsetUtil.UTF_8));

        pipeline.addLast(new MyClientHandler());
    }
}

public class MyClientHandler extends SimpleChannelInboundHandler<String> {
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {

        System.out.println(ctx.channel().remoteAddress());
        System.out.println("client output:"+msg);
        ctx.writeAndFlush("from client"+ LocalDateTime.now());
    }

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

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