MqttMessageNewDecoder.java

package io.mqtt.handler.coder;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToMessageDecoder;

import java.io.ByteArrayInputStream;
import java.util.List;

import org.meqantt.message.Message;
import org.meqantt.message.MessageInputStream;

public class MqttMessageNewDecoder extends MessageToMessageDecoder<ByteBuf> {

	@Override
	public void decode(ChannelHandlerContext ctx, ByteBuf buf,
			List<Object> out) throws Exception {
		if (buf.readableBytes() < 2) {
			return;
		}
		buf.markReaderIndex();
		buf.readByte(); // read away header
		int msgLength = 0;
		int multiplier = 1;
		int digit;
		int lengthSize = 0;
		do {
			lengthSize++;
			digit = buf.readByte();
			msgLength += (digit & 0x7f) * multiplier;
			multiplier *= 128;
			if ((digit & 0x80) > 0 && !buf.isReadable()) {
				buf.resetReaderIndex();
				return;
			}
		} while ((digit & 0x80) > 0);
		if (buf.readableBytes() < msgLength) {
			buf.resetReaderIndex();
			return;
		}
		byte[] data = new byte[1 + lengthSize + msgLength];
		buf.resetReaderIndex();
		buf.readBytes(data);
		MessageInputStream mis = new MessageInputStream(
				new ByteArrayInputStream(data));
		Message msg = mis.readMessage();
		mis.close();

		out.add(msg);
	}
}

这段代码是将ByteBuf 转换成byte数组？