netty服务双向认证

以下是一个使用Netty建立SSL双向认证的服务器和客户端的简单示例：

首先，确保你已经安装了Java和Maven，并且已经创建了一个Maven项目。

在pom.xml文件中添加以下依赖项：

<dependencies>
    <dependency>
        <groupId>io.netty</groupId>
        <artifactId>netty-all</artifactId>
        <version>4.1.65.Final</version>
    </dependency>
</dependencies>

接下来，创建一个Server类来实现服务器端的逻辑：

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
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 io.netty.handler.ssl.SslContext;
import io.netty.handler.ssl.SslContextBuilder;
import io.netty.handler.ssl.SslHandler;
import io.netty.handler.ssl.util.SelfSignedCertificate;

import javax.net.ssl.SSLEngine;
import java.security.cert.CertificateException;

public class Server {
    private static final int PORT = 8888;

    public static void main(String[] args) throws Exception {
        SelfSignedCertificate cert = new SelfSignedCertificate();
        SslContext sslContext = SslContextBuilder.forServer(cert.certificate(), cert.privateKey()).build();

        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
                        protected void initChannel(SocketChannel ch) throws Exception {
                            ChannelPipeline p = ch.pipeline();
                            SSLEngine engine = sslContext.newEngine(ch.alloc());
                            engine.setUseClientMode(false);
                            engine.setNeedClientAuth(true);
                            p.addLast(new SslHandler(engine));
                            p.addLast(new ServerHandler());
                        }
                    });

            ChannelFuture f = b.bind(PORT).sync();
            f.channel().closeFuture().sync();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

然后，创建一个ServerHandler类来处理服务器端的请求：

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;

public class ServerHandler extends ChannelInboundHandlerAdapter {
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        ByteBuf buf = (ByteBuf) msg;
        try {
            while (buf.isReadable()) {
                System.out.print((char) buf.readByte());
                System.out.flush();
            }
        } finally {
            buf.release();
        }
    }

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

最后，创建一个Client类来实现客户端的逻辑：

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
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 io.netty.handler.ssl.SslContext;
import io.netty.handler.ssl.SslContextBuilder;
import io.netty.handler.ssl.SslHandler;
import io.netty.handler.ssl.util.InsecureTrustManagerFactory;

import javax.net.ssl.SSLEngine;

public class Client {
    private static final String HOST = "localhost";
    private static final int PORT = 8888;

    public static void main(String[] args) throws Exception {
        SslContext sslContext = SslContextBuilder.forClient().trustManager(InsecureTrustManagerFactory.INSTANCE).build();

        EventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(group)
                    .channel(NioSocketChannel.class)
                    .handler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel ch) throws Exception {
                            ChannelPipeline p = ch.pipeline();
                            SSLEngine engine = sslContext.newEngine(ch.alloc(), HOST, PORT);
                            engine.setUseClientMode(true);
                            p.addLast(new SslHandler(engine));
                            p.addLast(new ClientHandler());
                        }
                    });

            ChannelFuture f = b.connect(HOST, PORT).sync();
            f.channel().closeFuture().sync();
        } finally {
            group.shutdownGracefully();
        }
    }
}

然后，创建一个ClientHandler类来处理客户端的请求：

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;

public class ClientHandler extends ChannelInboundHandlerAdapter {
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        String message = "Hello, server!";
        ByteBuf buf = ctx.alloc().buffer(message.length());
        buf.writeBytes(message.getBytes());
        ctx.writeAndFlush(buf);
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        ByteBuf buf = (ByteBuf) msg;
        try {
            while (buf.isReadable()) {
                System.out.print((char) buf.readByte());
                System.out.flush();
            }
        } finally {
            buf.release();
        }
    }

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

以上示例代码演示了如何使用Netty建立一个基于SSL双向认证的服务器和客户端。服务器端使用自签名证书，客户端信任任何服务器端的证书。