Netty引發IndexOutOfBoundsException

Question

我目前正在將Netty集成到將使用XML消息進行通信的服務器上。這些XML消息實際上是已被序列化爲XML消息的對象，然後通過TCP連接發送。我可以同時發送和接收的對象，但我得到的第二個消息，執行下列例外，我發送到服務器：

java.lang.IndexOutOfBoundsException: readerIndex(306) + length(613) exceeds writerIndex(614): UnpooledUnsafeDirectByteBuf(ridx: 306, widx: 614, cap: 1024) 
    at io.netty.buffer.AbstractByteBuf.checkReadableBytes(AbstractByteBuf.java:1161) 
    at io.netty.buffer.AbstractByteBuf.skipBytes(AbstractByteBuf.java:734) 
    at io.netty.buffer.WrappedByteBuf.skipBytes(WrappedByteBuf.java:540) 
    at io.netty.handler.codec.xml.XmlFrameDecoder.decode(XmlFrameDecoder.java:176) 
    at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:227) 

我有以下代碼初始化通道：

@Override 
public void initChannel(SocketChannel ch) throws Exception { 
    LOGGER.info("Accepted connection from " + ch.remoteAddress().toString()); 
    ClientConnection connection = new ClientConnection(ch); 
    ch.pipeline().addLast(new XmlFrameDecoder(6000), connection); 
} 

而下面的代碼來處理消息我收到：

@Override 
public void channelRead(ChannelHandlerContext ctx, Object msg) { 
    LOGGER.info("Got data"); 
    ByteBuf buf = (ByteBuf)msg; 
    try (ByteBufInputStream is = new ByteBufInputStream(buf)) { 
     Message message = MessageFactory.getInstance().deserialize(is); 
     // does stuff with message... 
    } catch (Throwable ex) { 
     LOGGER.log(Level.WARNING, ex.getMessage(), ex); 
    } finally { 
     ReferenceCountUtil.release(msg); 
    } 
} 

而這個代碼發送消息：

public void sendMessage(Message msg) { 
    ByteBufAllocator alloc = PooledByteBufAllocator.DEFAULT; 
    ByteBuf buf = alloc.buffer(1024); 

    try (ByteBufOutputStream outputStream = new ByteBufOutputStream(buf)) { 
     String message = MessageFactory.getInstance().serialize(msg) + "\0"; 
     outputStream.write(message.getBytes()); 
     this.socketChannel.writeAndFlush(buf); 
    } catch (IOException ex) { 
     LOGGER.log(Level.INFO, ex.getMessage(), ex); 
    } 
} 

我正在使用java.beans.XMLDecoder和XMLEncoder編碼/解碼XML對象。由於我發送的消息大小爲307，我認爲在處理消息後應該清除緩衝區，但事實並非如此。任何人有什麼想法可能是我的問題？

Answer 1

原來的問題是XMLEncoder在Netty開始讀取XML消息時搞砸了XML文檔的末尾處添加了一個\ n。