import io.netty.channel.Channel;import io.netty.channel.ChannelInitializer;import io.netty.handler.ssl.SslContext;import io.netty.handler.ssl.SslHandler;import javax.net.ssl.SSLEngine;public class SslChannelInitializer extends ChannelInitializer
     
       {    private final SslContext context;    private final boolean startTls;    // context:传入要使用的SslContext    // startTls:如果设置为true，第一个写入的消息将不会被加密（客户端应该设置为true）    public SslChannelInitializer(SslContext context,boolean startTls) {         this.context = context;        this.startTls = startTls;    }    @Override    protected void initChannel(Channel ch) throws Exception {        //对于每个SslHandler 实例，都使用Channel 的ByteBufAllocator 从SslContext 获取一个新的SSLEngine        SSLEngine engine = context.newEngine(ch.alloc());        //将SslHandler作为第一个ChannelHandler添加到ChannelPipeline 中        ch.pipeline().addFirst("ssl",new SslHandler(engine, startTls));       }}