Netty网络编程实战之搭建Netty服务器

下面我详细讲解一下“Netty网络编程实战之搭建Netty服务器”的完整攻略。

一、准备工作
1. 确认JDK版本是否为1.8及以上
2. 下载Netty 4.1以上版本的jar包
3. 安装Maven

二、创建项目
1.使用Maven创建项目

mvn archetype:generate -DgroupId=com.example -DartifactId=demo -DarchetypeArtifactId=maven-archetype-quickstart -Dinteracti        veMode=false

2.在pom.xml文件中添加Netty的依赖

<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-all</artifactId>
    <version>4.1.6.Final</version>
</dependency>

三、编写代码
1.创建Server类

public class Server {
    public static void main(String[] args) throws InterruptedException {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workerGroup)
             .channel(NioServerSocketChannel.class)
             .childHandler(new ChannelInitializer<SocketChannel>() {
                 @Override
                 public void initChannel(SocketChannel ch) throws Exception {
                     ch.pipeline().addLast(new ServerHandler());
                 }
             })
             .option(ChannelOption.SO_BACKLOG, 128)
             .childOption(ChannelOption.SO_KEEPALIVE, true);
            ChannelFuture f = b.bind(8080).sync();
            System.out.println("Server started.");
            f.channel().closeFuture().sync();
        } finally {
            workerGroup.shutdownGracefully();
            bossGroup.shutdownGracefully();
        }
    }
}

2.创建ServerHandler类

public class ServerHandler extends SimpleChannelInboundHandler<String> {
    @Override
    public void channelRead0(ChannelHandlerContext ctx, String msg) {
        System.out.println("Server received: " + msg);
        ctx.writeAndFlush("Hello, client.");
    }

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

四、运行程序
1.运行Server类，控制台显示“Server started.”
2.使用telnet连接服务端，在命令行输入以下命令：

telnet localhost 8080

3.在命令行输入字符串，回车后即可看到“Hello, client.”的回复。

五、示例说明
1.客户端发送多行信息，服务端只回复单行信息。
修改ServerHandler类

public class ServerHandler extends ChannelInboundHandlerAdapter {

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        ByteBuf in = (ByteBuf) msg;
        try {
            String request = in.toString(CharsetUtil.UTF_8);
            System.out.println(request);
            ctx.write(Unpooled.copiedBuffer("Hello, client.", CharsetUtil.UTF_8));
            ctx.flush();
        } finally {
            ReferenceCountUtil.release(msg);
        }
    }
}

2.服务端返回时间信息，
修改ServerHandler类

public class ServerHandler extends SimpleChannelInboundHandler<String> {
    @Override
    public void channelRead0(ChannelHandlerContext ctx, String msg) {
        System.out.println("Server received: " + msg);
        ctx.writeAndFlush( LocalTime.now() + " : " + msg);
    }

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

以上就是 “Netty网络编程实战之搭建Netty服务器”的完整攻略，希望对您有所帮助。