Question

我正在项目中用Netty4替换Netty3。我使用Google协议缓冲区作为数据传输。关闭在Netty3中正常工作的频道时我遇到了异常。

Bellowed是例外情况：

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:(消息是顶级协议缓冲区的接口。）

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));
    }
}

当我刚刚传输MathematicaTask对象时，它工作正常（客户端和服务器解析消息都正确）。但是当我关闭频道时，解码器会出现异常。

int dataLength = in.readInt();

有人能解决问题吗？蘑菇赞赏！

BTW：我尝试过ObjectEncoder和ObjectDecoder，然后一切都很好。所以我的解码器/编码器一定有问题。

Answer 1

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

这样的事情：

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));
    }
}

[Netty 4 CR2]使用用户定义的编码器和解码器关闭通道时出现异常

1 个答案: