netty拆分的套接字消息

Question

我编写了一个基于Netty4的REST服务器。客户端处理程序如下所示。

netty提供的msg中的bytebuffer容量各不相同。当客户端消息大于缓冲区时，消息将被拆分。我发现每个片段都调用channelRead和ChannelReadComplete。我通常看到的是ByteBuf在512左右，message在600左右。对于前512个字节，我得到一个channelRead，然后是一个ChannelReadComplete，然后是另一个channelRead，对于剩下的100个字节，还有一个ChannelReadComplete--2个消息，而不是1个。

public class ClientHandler extends ChannelInboundHandlerAdapter {
    ....
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        Report.debug("Read from client");
        ByteBuf buf = (ByteBuf) msg;
        String contents = buf.toString(io.netty.util.CharsetUtil.US_ASCII);
        ReferenceCountUtil.release(msg);

        ClientConnection client = ClientConnection.get(ctx);
        if (client != null) {
            client.messageText(contents);   // adds text to buffer
            return;
        }
        ((parse serial number from contents, process registration))
        ClientConnection.online(serialNumber, ctx);     // register success, create the client object
    }

    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ClientConnection client = ClientConnection.get(ctx);
        if (client == null) 
            Report.debug("completed read of message from unregistered client");
        else {
            Report.debug("completed read of message from client " + client.serialNumber());
            String contents = client.messageText();
            ... ((process message))
        }
    }
 }

Answer 1

channelReadComplete不在每个ChannelRead之后调用。netty事件循环将从NIO套接字读取并激发多个channelRead，直到没有更多的数据要读取或应该放弃为止，然后激发channelReadComplete。