Question

Netty 4.1.6（io.netty：netty-all：4.1.6.Final来自Gradle通过jcenter（），在OS X 10.11.6上使用Java 1.8.0_102）声明这是一个警告，但它实际上导致我的代码不做正确的事情。作为Netty的新手，我几乎肯定搞砸了，所以我想我会问专家。

我明白了：

[nioEventLoopGroup-2-1] WARN io.netty.util.ReferenceCountUtil - Failed to release a message: DatagramPacket(=> /127.0.0.1:54169, PooledUnsafeDirectByteBuf(freed))
io.netty.util.IllegalReferenceCountException: refCnt: 0, decrement: 1

来自此代码：

public void channelRead0(ChannelHandlerContext ctx, DatagramPacket packet) throws Exception {
    ByteBuf bb = Unpooled.copiedBuffer(packet.content());

    String ssHex = javax.xml.bind.DatatypeConverter.printHexBinary(bb.array());     
    System.out.println("IP:"+packet.sender()+":"+packet.recipient()+":"+ssHex);

    DatagramPacket udpPacket = new DatagramPacket(packet.content(), packet.sender());  // Using this line causes the exception at write
    //DatagramPacket udpPacket = new DatagramPacket(bb, packet.sender());  // Using this line succeeds
    ctx.write(udpPacket);  // Exception is thrown here
}

我做错了什么？谢谢你的帮助。

完全例外：

[nioEventLoopGroup-2-1] WARN io.netty.util.ReferenceCountUtil - Failed to release a message: DatagramPacket(=> /127.0.0.1:54169, PooledUnsafeDirectByteBuf(freed))
io.netty.util.IllegalReferenceCountException: refCnt: 0, decrement: 1
    at io.netty.buffer.AbstractReferenceCountedByteBuf.release0(AbstractReferenceCountedByteBuf.java:110)
    at io.netty.buffer.AbstractReferenceCountedByteBuf.release(AbstractReferenceCountedByteBuf.java:98)
    at io.netty.util.ReferenceCountUtil.release(ReferenceCountUtil.java:84)
    at io.netty.channel.DefaultAddressedEnvelope.release(DefaultAddressedEnvelope.java:101)
    at io.netty.util.ReferenceCountUtil.release(ReferenceCountUtil.java:84)
    at io.netty.util.ReferenceCountUtil.safeRelease(ReferenceCountUtil.java:109)
    at io.netty.channel.ChannelOutboundBuffer.remove0(ChannelOutboundBuffer.java:296)
    at io.netty.channel.ChannelOutboundBuffer.failFlushed(ChannelOutboundBuffer.java:621)
    at io.netty.channel.AbstractChannel$AbstractUnsafe.flush0(AbstractChannel.java:869)
    at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.flush0(AbstractNioChannel.java:362)
    at io.netty.channel.AbstractChannel$AbstractUnsafe.flush(AbstractChannel.java:823)
    at io.netty.channel.DefaultChannelPipeline$HeadContext.flush(DefaultChannelPipeline.java:1296)
    at io.netty.channel.AbstractChannelHandlerContext.invokeFlush0(AbstractChannelHandlerContext.java:787)
    at io.netty.channel.AbstractChannelHandlerContext.invokeFlush(AbstractChannelHandlerContext.java:779)
    at io.netty.channel.AbstractChannelHandlerContext.flush(AbstractChannelHandlerContext.java:760)
    at com.foobar.uservices.initial_receiver.InitialReceiverHandler.channelReadComplete(InitialReceiverHandler.java:24)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelReadComplete(AbstractChannelHandlerContext.java:409)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelReadComplete(AbstractChannelHandlerContext.java:391)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelReadComplete(AbstractChannelHandlerContext.java:384)
    at io.netty.channel.DefaultChannelPipeline$HeadContext.channelReadComplete(DefaultChannelPipeline.java:1339)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelReadComplete(AbstractChannelHandlerContext.java:409)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelReadComplete(AbstractChannelHandlerContext.java:391)
    at io.netty.channel.DefaultChannelPipeline.fireChannelReadComplete(DefaultChannelPipeline.java:932)
    at io.netty.channel.nio.AbstractNioMessageChannel$NioMessageUnsafe.read(AbstractNioMessageChannel.java:97)
    at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:651)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:574)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:488)
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:450)
    at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:873)
    at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:144)
    at java.lang.Thread.run(Thread.java:745)

Answer 1

很难从您的代码中看出，但看起来您可能正在使用SimpleChannelInboundHandler，它会自动释放任何传入的消息。由于您传递的是相同的缓冲区（只是以不同方式包装），因此需要在缓冲区上执行ReferenceCountUtil.retain（）。

注释掉的行成功，因为它是初始缓冲区的副本，因此它具有自己的引用计数。

文档： https://netty.io/4.0/api/io/netty/channel/SimpleChannelInboundHandler.html

新手：警告警告：WARN io.netty.util.ReferenceCountUtil - 无法发布消息

1 个答案: