Netty基础01-一个简单的nettyDemo

实现客户端发送请求到服务器，服务端返回一个hello netty

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

        //1.定义一对线程组（两队线程池）
        EventLoopGroup bossGroup = new NioEventLoopGroup();//主线程组，用于接收客户端的连接，但不做任何处理，跟老板一样，不做事
        EventLoopGroup workerGroup = new NioEventLoopGroup();//从线程组，老板线程组会把任务丢给他，让从线程组做任务

       try{
           //2.netty服务器的创建，serverBootStrap 是一个启动类
           ServerBootstrap serverBootstrap  =new ServerBootstrap();
           //group参数1 主线程组  参数2 从线程组
           serverBootstrap.group(bossGroup,workerGroup)//设置主从线程组
                   .channel(NioServerSocketChannel.class)//channel:当客户端和服务端连接之后，会有相应的双向通道产生，这里定义通道的类型：NioServerSocketChannel  通过class获得
                   .childHandler(new HelloServerInitializer());//子处理器，用于处理workgroup

           //启动server，并且设置8088为启动端口号，同时启动方式为同步
           ChannelFuture channelFuture = serverBootstrap.bind(8088).sync();

           //监听关闭的channel，设置为同步方式
           channelFuture.channel().closeFuture().sync();//以同步的方式监听channel关闭的行为
       }finally {
           //
           bossGroup.shutdownGracefully();
           workerGroup.shutdownGracefully();
       }

    }
}

public class HelloServerInitializer extends ChannelInitializer<SocketChannel> {



    @Override
    public void channelUnregistered(ChannelHandlerContext ctx) throws Exception {
        System.out.println("channel out.");
        super.channelUnregistered(ctx);
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("channel  活跃");
        super.channelActive(ctx);
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("channel 不活跃");
        super.channelInactive(ctx);
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        super.channelRead(ctx, msg);
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        System.out.println("channel读取完毕。。。");
        super.channelReadComplete(ctx);
    }

    @Override
    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
        System.out.println("用户事件触发");
        super.userEventTriggered(ctx, evt);
    }

    @Override
    public void channelWritabilityChanged(ChannelHandlerContext ctx) throws Exception {
        System.out.println("channel可写更改");
        super.channelWritabilityChanged(ctx);
    }

    @Override
    public boolean isSharable() {
        return super.isSharable();
    }

    @Override
    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
        System.out.println("助手类移除");
        super.handlerRemoved(ctx);
    }

    protected void initChannel(SocketChannel socketChannel) throws Exception {
        //通过socketchannel获取对应的管道(pipeline)
        ChannelPipeline pipeline = socketChannel.pipeline();

        //通过管道，添加handler
        //HttpServerCodec是netty提供的助手类，可以理解为拦截器
        //当请求到服务端，我们需要做解码，响应到客户端做编码
        pipeline.addLast("HttpServerCodec",new HttpServerCodec());

        //添加自定义助手类，返回“hello netty”
        pipeline.addLast("customHandler",new CustomHandler());
    }
}

//SimpleChannelInboundHandler :对于请求来讲，相当于【入站，入境】
public class CustomHandler extends SimpleChannelInboundHandler<HttpObject> {

    protected void channelRead0(ChannelHandlerContext channelHandlerContext, HttpObject httpObject)
            throws Exception {
             //获取当前的channel
        Channel channel = channelHandlerContext.channel();
        if(httpObject instanceof  HttpRequest){
            //显示客户端远程地址
            System.out.println(channel.remoteAddress());
            //定义发送的数据消息
            ByteBuf content = Unpooled.copiedBuffer("Hello netty", CharsetUtil.UTF_8);

            //构建一个 http response
            FullHttpResponse response =
                    new DefaultFullHttpResponse(HttpVersion.HTTP_1_1
                            , HttpResponseStatus.OK
                            ,content);
            //为响应增加数据类型和长度
            response.headers().set(HttpHeaderNames.CONTENT_TYPE,"text/plain");//设置数据类型
            response.headers().set(HttpHeaderNames.CONTENT_LENGTH,content.readableBytes());//设置数据长度

            //把响应刷到客户端
            channelHandlerContext.writeAndFlush(response);
        }



    }

}