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我在我的项目中用 Netty4 替换了 Netty3。我正在使用 Google-protocol-buffer 作为数据传输。关闭在 Netty3 中运行良好的通道时出现异常。

以下是异常详细信息：

io.netty.handler.codec.DecoderException: java.lang.IndexOutOfBoundsException: readerIndex(0) + length(4) exceeds writerIndex(0): PooledUnsafeDirectByteBuf(ridx: 0, widx: 0, cap: 4096)
    at io.netty.handler.codec.ByteToMessageDecoder.channelInactive(ByteToMessageDecoder.java:95)
    at io.netty.channel.DefaultChannelHandlerContext.invokeChannelInactive(DefaultChannelHandlerContext.java:801)
    at io.netty.channel.DefaultChannelHandlerContext.fireChannelInactive(DefaultChannelHandlerContext.java:787)
    at io.netty.channel.DefaultChannelPipeline.fireChannelInactive(DefaultChannelPipeline.java:808)
    at io.netty.channel.AbstractChannel$AbstractUnsafe$9.run(AbstractChannel.java:725)
    at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:364)
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:326)
    at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:114)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.IndexOutOfBoundsException: readerIndex(0) + length(4) exceeds writerIndex(0): PooledUnsafeDirectByteBuf(ridx: 0, widx: 0, cap: 4096)
    at io.netty.buffer.AbstractByteBuf.checkReadableBytes(AbstractByteBuf.java:1120)
    at io.netty.buffer.AbstractByteBuf.readInt(AbstractByteBuf.java:627)
    at com.fhq.mathematica.netty.MMADecoder.decode(MMADecoder.java:17)
    at io.netty.handler.codec.ByteToMessageDecoder.decodeLast(ByteToMessageDecoder.java:168)
    at io.netty.handler.codec.ByteToMessageDecoder.channelInactive(ByteToMessageDecoder.java:91)

这是编码器：（消息是顶层协议缓冲区的接口。）

public class MessageEncoder extends MessageToByteEncoder<Message>{
    @Override
    protected void encode(ChannelHandlerContext ctx, Message msg, ByteBuf out)
            throws Exception {
        byte[] data = msg.toByteArray();
        out.writeInt(data.length);
        out.writeBytes(data);
    }
}

这是解码器：

public class MMADecoder extends ByteToMessageDecoder{
    @Override
    protected void decode(ChannelHandlerContext ctx, ByteBuf in,
            MessageBuf<Object> out) throws Exception {
        in.markReaderIndex();
        int dataLength = in.readInt();
        if (in.readableBytes() < dataLength) {
            in.resetReaderIndex();
            return;
        }
        byte[] decoded = new byte[dataLength];
        in.readBytes(decoded);
        out.add(MathematicaTask.parseFrom(decoded));
    }
}

当我只是传输 MathematicaTask 对象时，它工作正常（客户端和服务器都正确解析消息）。但是当我关闭频道时，解码器会出现异常。

int dataLength = in.readInt();

谁能找出问题所在？穆什赞赏！

顺便说一句：我尝试了 ObjectEncoder 和 ObjectDecoder，然后一切都很好。所以我的解码器/编码器肯定有问题。

4

1 回答 1

0

在调用 ByteBuf.readInt() 之前，您需要检查是否有足够的字节来读取。

所以是这样的：

public class MMADecoder extends ByteToMessageDecoder{
    @Override
    protected void decode(ChannelHandlerContext ctx, ByteBuf in,
            MessageBuf<Object> out) throws Exception {
        if (in.readableBytes < 4) {
            return;
        }
        in.markReaderIndex();
        int dataLength = in.readInt();
        if (in.readableBytes() < dataLength) {
            in.resetReaderIndex();
            return;
        }
        byte[] decoded = new byte[dataLength];
        in.readBytes(decoded);
        out.add(MathematicaTask.parseFrom(decoded));
    }
}
于 2013-05-31T12:21:03.417 回答