Netty初探-netty服务端和客户端demo

忘是亡心i 2022-09-25 14:23 377阅读 0赞

通过netty框架实现一个简单的服务端和客户端框架，相比于前面所说的NIO，netty的api使用更加简单灵活，扩展性强。

  • TimeServer

    package com.xpn.netty.netty;

    import io.netty.bootstrap.ServerBootstrap;
    import io.netty.channel.ChannelFuture;
    import io.netty.channel.ChannelInitializer;
    import io.netty.channel.ChannelOption;
    import io.netty.channel.EventLoopGroup;
    import io.netty.channel.nio.NioEventLoopGroup;
    import io.netty.channel.socket.SocketChannel;
    import io.netty.channel.socket.nio.NioServerSocketChannel;

    public class TimeServer {

    1. public void bind(int port) throws InterruptedException {
    2.     // 配置NIO线程组
    3.     EventLoopGroup bossGroup = new NioEventLoopGroup()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;// 连接线程</span>
    4.     EventLoopGroup workerGroup = new NioEventLoopGroup()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;// 处理线程组</span>
    5.     try {
    6.         ServerBootstrap bootstrap = new ServerBootstrap()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    7.         bootstrap<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.group</span>(bossGroup, workerGroup)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    8.         bootstrap<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.channel</span>(NioServerSocketChannel<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.class</span>)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    9.         bootstrap<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.option</span>(ChannelOption<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.SO</span>_BACKLOG, <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1024</span>)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    10.         bootstrap<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.childHandler</span>(new ChildChannelHandler())<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    11.         // 绑定端口，同步等待成功
    12.         ChannelFuture future = bootstrap<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.bind</span>(port)<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.sync</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    13.         // 等待服务端监听端口关闭，等待服务端链路关闭之后main函数才退出
    14.         future<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.channel</span>()<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.closeFuture</span>()<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.sync</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    15.     } finally {
    16.         // 优雅退出，释放线程池资源
    17.         bossGroup<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.shutdownGracefully</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    18.         workerGroup<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.shutdownGracefully</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    19.     }
    21. }
    23. private class ChildChannelHandler extends ChannelInitializer<SocketChannel> {
    25.     @Override
    26.     protected void initChannel(SocketChannel ch) throws Exception {
    27.         ch<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.pipeline</span>()<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.addLast</span>(new TimeServerHandler())<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    29.     }
    31. }
    33. public static void main(String[] args) throws InterruptedException {
    34.     int port = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">8080</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    35.     if (args != null && args<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.length</span> > <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>) {
    36.         port = Integer<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.parseInt</span>(args[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>])<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    37.     }
    38.     new TimeServer()<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.bind</span>(port)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    40. }

    }

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  • TimeClient

    package com.xpn.netty.netty;

    import io.netty.bootstrap.Bootstrap;
    import io.netty.channel.ChannelFuture;
    import io.netty.channel.ChannelInitializer;
    import io.netty.channel.ChannelOption;
    import io.netty.channel.EventLoopGroup;
    import io.netty.channel.nio.NioEventLoopGroup;
    import io.netty.channel.socket.SocketChannel;
    import io.netty.channel.socket.nio.NioSocketChannel;

    public class TimeClient {

    1. <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**
    2.  * @param args
    3.  */</span>
    4. public static void main(String[] args) {
    5.     // TODO Auto-generated method stub
    6.     String host = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"localhost"</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    7.     int port = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">8080</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    8.     EventLoopGroup workerGroup = new NioEventLoopGroup()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    9.     try {
    10.         Bootstrap bootstrap = new Bootstrap()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    11.         bootstrap<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.group</span>(workerGroup)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    12.         bootstrap<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.channel</span>(NioSocketChannel<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.class</span>)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    13.         bootstrap<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.option</span>(ChannelOption<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.SO</span>_KEEPALIVE, true)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    14.         bootstrap<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.handler</span>(new ChannelInitializer<SocketChannel>() {
    16.             @Override
    17.             protected void initChannel(SocketChannel ch) throws Exception {
    18.                 ch<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.pipeline</span>()<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.addLast</span>(new TimeClientHandler())<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    20.             }
    21.         })<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    22.         // 发起异步连接操作
    23.         ChannelFuture future = bootstrap<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.connect</span>(host, port)<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.sync</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    25.         future<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.channel</span>()<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.closeFuture</span>()<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.sync</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    26.     } catch (Exception e) {
    27.         workerGroup<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.shutdownGracefully</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    28.     }
    29. }

    }

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  • TimeServerHandler

    package com.xpn.netty.netty;

    import io.netty.buffer.ByteBuf;
    import io.netty.buffer.Unpooled;
    import io.netty.channel.ChannelHandlerAdapter;
    import io.netty.channel.ChannelHandlerContext;

    import java.util.Date;

    public class TimeServerHandler extends ChannelHandlerAdapter {

    1. <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
    2. <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">exceptionCaught</span>(ChannelHandlerContext ctx, Throwable cause)
    3.         <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throws</span> Exception {
    4.     <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// TODO Auto-generated method stub</span>
    5.     cause.printStackTrace();
    6.     ctx.close();
    7. }
    9. <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
    10. <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">channelRead</span>(ChannelHandlerContext ctx, Object msg)
    11.         <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throws</span> Exception {
    12.     ByteBuf buf = (ByteBuf) msg;
    13.     <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">byte</span>[] req = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">byte</span>[buf.readableBytes()];<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 获得缓冲区可读的字节数</span>
    14.     buf.readBytes(req);
    15.     String body = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> String(req, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"UTF-8"</span>);
    16.     System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"the time server receive order : "</span> + body);
    17.     String currentTime = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"query time order"</span>.equalsIgnoreCase(body) ? <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Date(
    18.             System.currentTimeMillis()).toString() : <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"bad order"</span>;
    19.     ByteBuf resp = Unpooled.copiedBuffer(currentTime.getBytes());
    20.     ctx.write(resp);<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 性能考虑，仅将待发送的消息发送到缓冲数组中，再通过调用flush方法，写入channel中</span>
    21. }
    23. <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
    24. <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">channelReadComplete</span>(ChannelHandlerContext ctx) <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throws</span> Exception {
    25.     ctx.flush();<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 将消息发送队列中的消息写入到SocketChannel中发送给对方。</span>
    26. }

    }

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  • TimeClientHandler

    package com.xpn.netty.netty;

    import io.netty.buffer.ByteBuf;
    import io.netty.buffer.Unpooled;
    import io.netty.channel.ChannelHandlerAdapter;
    import io.netty.channel.ChannelHandlerContext;

    import java.util.logging.Logger;

    public class TimeClientHandler extends ChannelHandlerAdapter {

    1. <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> Logger LOGGER = Logger
    2.         .getLogger(TimeClientHandler.class.getName());
    3. <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> ByteBuf firstMessage;
    5. <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-title" style="box-sizing: border-box;">TimeClientHandler</span>() {
    6.     <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">byte</span>[] req = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"query time order"</span>.getBytes();
    7.     firstMessage = Unpooled.buffer(req.length);
    8.     firstMessage.writeBytes(req);
    9. }
    11. <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
    12. <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">channelActive</span>(ChannelHandlerContext ctx) <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throws</span> Exception {
    13.     ctx.writeAndFlush(firstMessage);<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 将请求消息发送给服务端</span>
    14. }
    16. <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
    17. <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">exceptionCaught</span>(ChannelHandlerContext ctx, Throwable cause)
    18.         <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throws</span> Exception {
    19.     LOGGER.warning(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Unexpected exception from downstrema : "</span>
    20.             + cause.getMessage());
    21.     ctx.close();
    22. }
    24. <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
    25. <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">channelRead</span>(ChannelHandlerContext ctx, Object msg)
    26.         <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throws</span> Exception {
    27.     ByteBuf buf = (ByteBuf) msg;
    28.     <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">byte</span>[] req = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">byte</span>[buf.readableBytes()];
    29.     buf.readBytes(req);
    30.     String body = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> String(req, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"UTF-8"</span>);
    31.     System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Now is : "</span> + body);
    33. }

    }

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