测试程序

使用下面命令启动服务器：

mvn -PChatServer clean package exec:exec

其中项目中的 pom.xml 是配置了 9999 端口。你也可以通过下面的方法修改属性

mvn -PChatServer -Dport=1111 clean package exec:exec

下面是控制台的输出

Listing 11.5 Compile and start the ChatServer

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building ChatServer 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
...
[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ netty-in-action ---
[INFO] Building jar: D:/netty-in-action/chapter11/target/chat-server-1.0-SNAPSHOT.jar
[INFO]
[INFO] --- exec-maven-plugin:1.2.1:exec (default-cli) @ chat-server ---
Starting ChatServer on port 9999

可以在浏览器中通过 http://localhost:9999 地址访问程序：

Figure 11.5 WebSockets ChatServer demonstration

图中显示了两个客户端可以交互了。

如何加密？

通过添加 SslHandler 到 ChannelPipeline 来配置加密。如下：

Listing 11.6 Add encryption to the ChannelPipeline

public class SecureChatServerIntializer extends ChatServerInitializer {    //1
    private final SslContext context;

    public SecureChatServerIntializer(ChannelGroup group, SslContext context) {
        super(group);
        this.context = context;
    }

    @Override
    protected void initChannel(Channel ch) throws Exception {
        super.initChannel(ch);
        SSLEngine engine = context.newEngine(ch.alloc());
        engine.setUseClientMode(false);
        ch.pipeline().addFirst(new SslHandler(engine)); //2
    }
}

1.扩展 ChatServerInitializer 来实现加密

2.SslHandler 到 ChannelPipeline

最后修改 ChatServer，使用 SecureChatServerInitializer 并传入 SSLContext

Listing 11.7 Add encryption to the ChatServer

public class SecureChatServer extends ChatServer {//1

    private final SslContext context;

    public SecureChatServer(SslContext context) {
        this.context = context;
    }

    @Override
    protected ChannelInitializer<Channel> createInitializer(ChannelGroup group) {
        return new SecureChatServerIntializer(group, context);    //2
    }

    public static void main(String[] args) throws Exception{
        if (args.length != 1) {
            System.err.println("Please give port as argument");
            System.exit(1);
        }
        int port = Integer.parseInt(args[0]);
        SelfSignedCertificate cert = new SelfSignedCertificate();
        SslContext context = SslContext.newServerContext(cert.certificate(), cert.privateKey());
        final SecureChatServer endpoint = new SecureChatServer(context);
        ChannelFuture future = endpoint.start(new InetSocketAddress(port));

        Runtime.getRuntime().addShutdownHook(new Thread() {
            @Override
            public void run() {
                endpoint.destroy();
            }
        });
        future.channel().closeFuture().syncUninterruptibly();
    }
}

1.扩展 ChatServer

2.返回先前创建的 SecureChatServerInitializer 来启动加密

这样，就在所有的通信中使用了 SSL/TLS 加密。下面是启动程序：

Listing 11.8 Start the SecureChatServer

$ mvn -PSecureChatServer clean package exec:exec
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building ChatServer 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
...
[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ netty-in-action ---
[INFO] Building jar: D:/netty-in-action/chapter11/target/chat-server-1.0-SNAPSHOT.jar
[INFO]
[INFO] --- exec-maven-plugin:1.2.1:exec (default-cli) @ chat-server ---
Starting SecureChatServer on port 9999

可以通过 HTTPS 地址: https://localhost:9999 来访问SecureChatServer