Netty java 从 ByteBuf 获取数据
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/19296386/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Netty java getting data from ByteBuf
提问by NiceTheo
How to get a byte array from ByteBufefficiently in the code below? I need to get the array and then serialize it.
如何ByteBuf在下面的代码中有效地获取字节数组？我需要获取数组然后对其进行序列化。
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();
}
}
采纳答案by trustin
ByteBuf buf = ...
byte[] bytes = new byte[buf.readableBytes()];
buf.readBytes(bytes);
If you don't want the readerIndex to change:
如果您不希望 readerIndex 改变：
ByteBuf buf = ...
byte[] bytes = new byte[buf.readableBytes()];
int readerIndex = buf.readerIndex();
buf.getBytes(readerIndex, bytes);
If you want to minimize the memory copy, you can use the backing array of the ByteBuf, if it's available:
如果要最小化内存副本，可以使用 的后备数组（ByteBuf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;
}
Please note that you can't simply use buf.array(), because:
请注意，您不能简单地使用buf.array()，因为：
- Not all
ByteBufs have backing array. Some are off-heap buffers (i.e. direct memory) - Even if a
ByteBufhas a backing array (i.e.buf.hasArray()returnstrue), the following isn't necessarily true because the buffer might be a slice of other buffer or a pooled buffer:buf.array()[0] == buf.getByte(0)buf.array().length == buf.capacity()
- 并非所有
ByteBufs 都有后备数组。有些是堆外缓冲区（即直接内存） - 即使 a
ByteBuf有一个后备数组（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的一部分或池缓冲区：buf.array()[0] == buf.getByte(0)buf.array().length == buf.capacity()
