Java搭建简单Netty开发环境入门教程

下面就是准备Netty的jar包了，如果你会maven的话自然是使用maven最为方便了。只需要在pom文件中导入以下几行

<!-- https://mvnrepository.com/artifact/io.netty/netty-all -->
    <dependency>
      <groupId>io.netty</groupId>
      <artifactId>netty-all</artifactId>
      <version>4.1.16.Final</version>
    </dependency>

当然啦，不会maven的也不用愁，可以在官网直接下载jar包，点击跳转。并在编辑器中将下载的jar包引入你的lib中，就可以愉快的开始Netty开发了

下面贴一个简单的netty案例

一、 服务端代码

1. EchoServerHandler.java

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandler.Sharable;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.CharsetUtil;

@Sharable
public class EchoServerHandler extends ChannelInboundHandlerAdapter{
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        //将客户端传入的消息转换为Netty的ByteBuf类型
        ByteBuf in = (ByteBuf) msg;

        // 在控制台打印传入的消息
        System.out.println(
                "Server received: " + in.toString(CharsetUtil.UTF_8)
        );
        //将接收到的消息写给发送者，而不冲刷出站消息
        ctx.write(in);
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        // 将未处决消息冲刷到远程节点， 并且关闭该Channel
        ctx.writeAndFlush(Unpooled.EMPTY_BUFFER)
                .addListener(ChannelFutureListener.CLOSE);
    }

    /**
     * 异常处理
     * @param ctx
     * @param cause
     * @throws Exception
     */
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        //打印异常栈跟踪
        cause.printStackTrace();

        // 关闭该Channel
        ctx.close();
    }
}

2. EchoServer.java

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

import java.net.InetSocketAddress;

public class EchoServer {
    private final static int port = 8080;

    public static void main(String[] args) {
        start();
    }

    private static void start() {
        final EchoServerHandler serverHandler = new EchoServerHandler();
        // 创建EventLoopGroup
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        // 创建EventLoopGroup
        ServerBootstrap b = new ServerBootstrap();
        b.group(bossGroup, workerGroup)
                //指定所使用的NIO传输Channel
        .channel(NioServerSocketChannel.class)
                //使用指定的端口设置套接字地址
        .localAddress(new InetSocketAddress(port))
                // 添加一个EchoServerHandler到Channle的ChannelPipeline
        .childHandler(new ChannelInitializer<SocketChannel>() {
            @Override
            protected void initChannel(SocketChannel socketChannel) throws Exception {
                //EchoServerHandler被标注为@shareable,所以我们可以总是使用同样的案例
                socketChannel.pipeline().addLast(serverHandler);
            }
        });

        try {
            // 异步地绑定服务器;调用sync方法阻塞等待直到绑定完成
            ChannelFuture f = b.bind().sync();
            // 获取Channel的CloseFuture，并且阻塞当前线程直到它完成
            f.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            // 优雅的关闭EventLoopGroup，释放所有的资源
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

二、 客户端代码

1. EchoClientHandler.java

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandler.Sharable;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.util.CharsetUtil;

@Sharable
public class EchoClientHandler extends SimpleChannelInboundHandler<ByteBuf> {
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        //当被通知Channel是活跃的时候，发送一条消息
        ctx.writeAndFlush(Unpooled.copiedBuffer("Netty rocks!", CharsetUtil.UTF_8));
    }

    @Override
    protected void channelRead0(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf) throws Exception {
        System.out.println(
                "Client received: " + byteBuf.toString(CharsetUtil.UTF_8)
        );
    }

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

2. EchoClient.java

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

import java.net.InetSocketAddress;

public class EchoClient {
    private final static String HOST = "localhost";
    private final static int PORT = 8080;

    public static void start() {
        EventLoopGroup group = new NioEventLoopGroup();
        Bootstrap bootstrap = new Bootstrap();
        bootstrap.group(group)
                .channel(NioSocketChannel.class)
                .remoteAddress(new InetSocketAddress(HOST, PORT))
                .handler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    protected void initChannel(SocketChannel socketChannel) throws Exception {
                        socketChannel.pipeline().addLast(new EchoClientHandler());
                    }
                });
        try {
            ChannelFuture f = bootstrap.connect().sync();
            f.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }finally {
            group.shutdownGracefully();
        }
    }

    public static void main(String[] args) {
        start();
    }
}

先后运行EchoServer.java和EchoClient.java.如果控制台分别打印了

Server received: Netty rocks!

和

Client received: Netty rocks!

那么恭喜你，你已经可以开始netty的开发了。

点击查看Netty结合Protobuf编解码

到此这篇关于Java搭建简单Netty开发环境入门教程的文章就介绍到这了,更多相关Java搭建Netty环境内容请搜索服务器之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持服务器之家！

原文链接：https://blog.csdn.net/qq_33227649/article/details/78317912