Netty java从ByteBuf获取数据
如何在下面的代码中有效地从ByteBuf
获取字节数组? 我需要获取数组然后序列化它。
package testingNetty; import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelInboundHandlerAdapter; public class ServerHandler extends ChannelInboundHandlerAdapter { @Override public void channelRead(ChannelHandlerContext ctx, Object msg) { System.out.println("Message receive"); ByteBuf buff = (ByteBuf) msg; // There is I need get bytes from buff and make serialization byte[] bytes = BuffConvertor.GetBytes(buff); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { // Close the connection when an exception is raised. cause.printStackTrace(); ctx.close(); } }
ByteBuf buf = ... byte[] bytes = new byte[buf.readableBytes()]; buf.readBytes(bytes);
如果您不希望readerIndex更改:
ByteBuf buf = ... byte[] bytes = new byte[buf.readableBytes()]; int readerIndex = buf.readerIndex(); buf.getBytes(readerIndex, bytes);
如果要最小化内存副本,可以使用ByteBuf
的后备数组(如果可用):
ByteBuf buf = ... byte[] bytes; int offset; int length = buf.readableBytes(); if (buf.hasArray()) { bytes = buf.array(); offset = buf.arrayOffset(); } else { bytes = new byte[length]; buf.getBytes(buf.readerIndex(), bytes); offset = 0; }
请注意,您不能简单地使用buf.array()
,因为:
- 并非所有
ByteBuf
都有后备arrays。 一些是堆外缓冲区(即直接内存) - 即使
ByteBuf
具有后备数组(即buf.hasArray()
返回true
),以下情况也不一定正确,因为缓冲区可能是其他缓冲区或池缓冲区的片段:-
buf.array()[0] == buf.getByte(0)
-
buf.array().length == buf.capacity()
-