java.lang.IndexOutOfBoundsException: writerIndex(89) + minWritableBytes(61) exceeds maxCapacity(89): UnpooledHeapByteBuf(ridx: 89, widx: 89, cap: 89/89)
at io.netty.buffer.AbstractByteBuf.ensureWritable(AbstractByteBuf.java:243)
at io.netty.buffer.AbstractByteBuf.writeBytes(AbstractByteBuf.java:819)
at io.netty.buffer.AbstractByteBuf.writeBytes(AbstractByteBuf.java:827)
at com.ExgMsgRegister(VehicleDynamicInfoExchangeHandler.java:147)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:163)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319)
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)
at io.netty.handler.codec.MessageToMessageCodec.channelRead(MessageToMessageCodec.java:111)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:787)
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:125)
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:511)
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:468)
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:382)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:354)
at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116)
at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:137)
at java.lang.Thread.run(Thread.java:745)
通过异常信息可知到，已经是字节写入溢出
minWritableBytes(61)允许写入的字节数是61个字节，
maxCapacity(89)最大容量是89个字节，
writerIndex(89)已写入89个字节
跟踪源码，可以知道超过可写入容量直接抛出异常
if (minWritableBytes > maxCapacity - writerIndex) {
throw new IndexOutOfBoundsException(String.format(
"writerIndex(%d) + minWritableBytes(%d) exceeds maxCapacity(%d): %s",
writerIndex, minWritableBytes, maxCapacity, this));
}
解决方法:根据可用字计数重新分配buff缓存
data = Unpooled.buffer(data.readableBytes());
data.writeBytes(dataDebug);
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