netty介绍:

1.认识netty

官方介绍:Netty is an asynchronous event-driven network application framework  for rapid development of maintainable high performance protocol servers & clients

Netty 是 一个异步事件驱动的网络应用程序框架,用于快速开发可维护的高性能协议服务器和客户端。

Netty是一个NIO客户端服务器框架,可以快速轻松地开发网络应用程序,例如协议服务器和客户端。它极大地简化和精简了 TCP 和 UDP 套接字服务器等网络编程。“快速简便”并不意味着最终的应用程序将遭受可维护性或性能问题的困扰。Netty 是根据从许多协议(例如 FTP、SMTP、HTTP 以及各种基于二进制和文本的遗留协议)的实现中获得的经验而精心设计的。结果,Netty 成功地找到了一种方法,可以在不妥协的情况下实现易于开发、性能、稳定性和灵活性。

2.netty api简单使用

ByteBuf byteBuf;
    @Before
    public void byteBufCommonTest(){
         /**Bytebuf的多种分配方式*/
         byteBuf= ByteBufAllocator.DEFAULT.buffer(8,12);
         ByteBufAllocator.DEFAULT.heapBuffer(8,12);
         ByteBufAllocator.DEFAULT.directBuffer(8,12);
         UnpooledByteBufAllocator.DEFAULT.heapBuffer(8,12);
        /**分配一个ByteBuf 初始大小为8,最大为12*/
    }
    @Test
    public void mainTest(){
            testReadAndWrite();
            byteBuf.writeBytes(new byte[]{'d', 'd', 'f', 'g'});
            testReadAndWrite();
            byteBuf.writeBytes(new byte[]{'d', 'd', 'f', 'g'});
            testReadAndWrite();
            byteBuf.writeBytes(new byte[]{'d', 'd'});
            testReadAndWrite();
            System.out.println(byteBuf);
            while (byteBuf.isReadable()) {
                System.out.println((char) byteBuf.readByte());
            }
    }
    @Test
    public void testReadAndWrite(){
        System.out.println("byteBuf.isWritable():"+byteBuf.isWritable());
        System.out.println("byteBuf.writerIndex():"+byteBuf.writerIndex());
        System.out.println("byteBuf.writableBytes():"+byteBuf.writableBytes());
        System.out.println("byteBuf.isReadable():"+byteBuf.isReadable());
        System.out.println("byteBuf.readerIndex():"+byteBuf.readerIndex());
        System.out.println("byteBuf.readableBytes():"+byteBuf.readableBytes());
        System.out.println("=====================================");
    }

测试mainTest(),输出如下,可以看出,当byteBuf中有数据时可以读取,而且,当写入时达到默认大小时,会进行扩展,到最大值,超出了最大值将报错!

byteBuf.isWritable():true
byteBuf.writerIndex():0
byteBuf.writableBytes():8
byteBuf.isReadable():false
byteBuf.readerIndex():0
byteBuf.readableBytes():0
=====================================
byteBuf.isWritable():true
byteBuf.writerIndex():4
byteBuf.writableBytes():4
byteBuf.isReadable():true
byteBuf.readerIndex():0
byteBuf.readableBytes():4
=====================================
byteBuf.isWritable():false
byteBuf.writerIndex():8
byteBuf.writableBytes():0
byteBuf.isReadable():true
byteBuf.readerIndex():0
byteBuf.readableBytes():8
=====================================
byteBuf.isWritable():true
byteBuf.writerIndex():10
byteBuf.writableBytes():2
byteBuf.isReadable():true
byteBuf.readerIndex():0
byteBuf.readableBytes():10
=====================================
PooledUnsafeDirectByteBuf(ridx: 0, widx: 10, cap: 12/12)
d
d
f
g
d
d
f
g
d
d

3.简单的netty交互

netty介绍:

 

 程序编写neety客户端:

 @Test
    public void ClinetTest() throws Exception{
        NioSocketChannel channel=new NioSocketChannel();
        NioEventLoopGroup group=new NioEventLoopGroup(1);
        group.register(channel);
        ChannelFuture future=channel.connect(new InetSocketAddress("192.168.72.200",9999));
        //future.sync();
        ChannelFuture future1w=channel.writeAndFlush(Unpooled.copiedBuffer("sdfsdfsdf".getBytes()));
        //future1w.sync();/**意思是要等待future1w执行完成,其实就是将异步执行转换为同步执行*/
        Thread.sleep(10000);
    }

执行之后结果显示:如果不使用future1w.sync()做同步处理,当方法中的程序执行完成之后,整个程序结束,客户端关闭,如果消息还未发送至服务端,将会停止,服务端从头到尾也没有接收到任何信息

netty介绍:

 

 4.双向交互

 @Test
    public void doubleClientTest() throws Exception{
        NioEventLoopGroup group=new NioEventLoopGroup(2);
        NioSocketChannel channel=new NioSocketChannel();
        group.register(channel);
        ChannelFuture connectFuture=channel.connect(new InetSocketAddress("192.168.72.200",9999));
        ChannelPipeline pipeline=channel.pipeline();/**获取通道*/
        pipeline.addLast(new MyHandler());
        ChannelFuture channelFuture=connectFuture.sync();
        channelFuture.channel().closeFuture().sync();/**等待通道关闭*/
    }


class MyHandler extends ChannelInboundHandlerAdapter {
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        ByteBuf byteBuf=(ByteBuf)msg;
        System.out.println(byteBuf.getCharSequence(0,byteBuf.readableBytes(), CharsetUtil.UTF_8));
        ctx.writeAndFlush(byteBuf);
    }
}

执行结果:

netty介绍:

 

 netty介绍:

 

 服务端发送一条消息,经过客户端会写,在服务端展示信息

 5.服务端举例:

 @Test
    public void doubleTClientTest() throws Exception{
      NioEventLoopGroup group=new NioEventLoopGroup(2);
        ServerBootstrap bootstrap=new ServerBootstrap();
      ChannelFuture future=  bootstrap.group(group,group).
                channel(NioServerSocketChannel.class).
                childHandler(new ChannelInitializer<NioSocketChannel>() {
            @Override
            protected void initChannel(NioSocketChannel ch) throws Exception {
                ChannelPipeline pipeline=  ch.pipeline();
                pipeline.addLast(new MyHandler());
            }
        }).bind("192.168.72.1",8080);
        future.sync().channel().closeFuture().sync();
    }



}
class MyHandler extends ChannelInboundHandlerAdapter {
    @Override
    public void channelRegistered(ChannelHandlerContext ctx) throws Exception {
        System.out.println("regist:"+ctx.channel().remoteAddress());
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        ByteBuf byteBuf=(ByteBuf)msg;
        System.out.println(byteBuf.getCharSequence(0,byteBuf.readableBytes(), CharsetUtil.UTF_8));
        ctx.writeAndFlush(byteBuf);
    }
}

netty介绍:

 

 netty介绍:

 

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