自定義協議格式

%1$8s%2$4s%3$4s%4$8s%5$16s%6$32s%7$8s

類似：AAAAAAAA0001000011001001usernameusernamesession1session1session1session100000023

參考程式碼

package com.phei.netty.codec.custom;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.PooledByteBufAllocator;
import
 
 io.netty.buffer.Unpooled;
import io.netty.buffer.UnpooledByteBufAllocator;
import io.netty.buffer.UnpooledDirectByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.ByteToMessageDecoder;
import io.netty.handler.codec.CorruptedFrameException;
import io.netty.util.ReferenceCountUtil;



/**
 * 
 * @author
 
 Administrator
 * <pre>
 *  BEFORE DECODE                                    AFTER DECODE
 * +------+--------+----------------+------+        +----------------+
 * | head | Length |      body      | tail |------->|    body        |
 * | int  |   int  |   some bytes   |  int |        |   some bytes   |
 * +------+--------+----------------+------+        +----------------+
 * </pre>
 */
 

public class CustomDecoder2 extends ByteToMessageDecoder {

    private static final ByteBuf HEAD_FLAG = Unpooled.copyInt(0x77aa77aa);
    private static final int TAIL_FLAG = 0x77ab77ab;
    private static java.util.concurrent.atomic.AtomicInteger  c= new AtomicInteger(1);

    @Override
    protected void decode(ChannelHandlerContext ctx, ByteBuf in,
            List<Object> out) throws Exception {
        Object o = decode(ctx, in);
        if (o != null) {
            out.add(o);
            System.err.println(c.getAndIncrement());
        }
    }

    private Object decode(ChannelHandlerContext ctx, ByteBuf in) {

        in.markReaderIndex();
        //查詢包頭位置
        int headerOffset = indexOf(in, HEAD_FLAG);

        if (headerOffset < 0) {
            //找不到包頭,丟棄多餘位元組
            if(in.readableBytes() > 3)
                in.skipBytes(in.readableBytes()-3);
            return null;
        } else {
            //找到包頭，跳到包頭結束位置
            in.skipBytes(headerOffset + 4);
        }

        //如發現剩餘位元組不夠4位，回滾指標，等待下次解碼
        if (in.readableBytes() < 4) {
            in.resetReaderIndex();
            return null;
        }

        //讀取length
        int bodyLength = in.readInt();
        //非法length，丟棄全部位元組，等待下次解碼
        if (bodyLength < 0) {
            return null;
        }

        //計算剩餘位元組數(包體 +包尾)
        int len = bodyLength + 4;

        //如剩餘位元組不夠，回滾指標，等待下次解碼
        if (in.readableBytes() < len) {
            in.resetReaderIndex();
            return null;
        }

        //獲取包體
        ByteBuf frame = ctx.alloc().buffer(bodyLength);
        in.readBytes(frame);

        //讀取包尾
        int tail = in.readInt();

        //包尾不匹配，則丟棄包體，等待下次解碼
        if (tail != TAIL_FLAG) {
            ReferenceCountUtil.release(frame);
            return null;
        }
        return frame;
    }

    private static int indexOf(ByteBuf haystack, ByteBuf needle) {
        for (int i = haystack.readerIndex(); i < haystack.writerIndex(); i++) {
            int haystackIndex = i;
            int needleIndex;
            for (needleIndex = 0; needleIndex < needle.capacity(); needleIndex++) {
                if (haystack.getByte(haystackIndex) != needle
                        .getByte(needleIndex)) {
                    break;
                } else {
                    haystackIndex++;
                    if (haystackIndex == haystack.writerIndex()
                            && needleIndex != needle.capacity() - 1) {
                        return -1;
                    }
                }
            }

            if (needleIndex == needle.capacity()) {
                // Found the needle from the haystack!
                return i - haystack.readerIndex();
            }
        }
        return -1;
    }

    public static void main(String[] args) {
        ByteBuf haystack = Unpooled.buffer();
        haystack.writeShort(2);
        ByteBuf needle = Unpooled.copyInt(0x77aa77aa);
        // needle.writeInt(0x77aa77aa);
        System.out.println(indexOf(haystack, needle));
        System.out.println(haystack.readerIndex());

    }
}

我的程式碼

解碼器：

package com.phei.netty.codec.custom;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.ByteToMessageDecoder;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * CustomDecoder.java 說明
 * 
 * <pre>
 *  BEFORE DECODE                                    AFTER DECODE
 *  
 *  Head                                                    Body
 *  長度80：%1$8s%2$4s%3$4s%4$8s%5$16s%6$32s%7$8s             不定長
 *  (16, 24)命令id，(72, 80)包體長度
 * 
 * </pre>
 * 
 * @author zhengzy
 * @date 2015年12月24日上午10:50:26
 */
public class CustomDecoder extends ByteToMessageDecoder {
    private static int HEADER_SIZE = 80;
    private static int dstStartPos = 72;
    private static int dstStopPos = 80;
    private static ByteBuf buf = Unpooled.buffer();
    private static java.util.concurrent.atomic.AtomicInteger c = new AtomicInteger(1);

    @Override
    protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
        // TODO Auto-generated method stub
        Object o = decode(ctx, in);
        if (o != null) {
            out.add(o);
            System.out.println(c.getAndIncrement());
        }
    }

    private Object decode(ChannelHandlerContext ctx, ByteBuf in) throws Exception {

        //標記讀指標位置，以便可以回滾指標
        in.markReaderIndex();

        // 如發現剩餘位元組不夠80位，回滾指標，等待下次解碼
        if (in.readableBytes() < HEADER_SIZE) {
            in.resetReaderIndex();
            return null;
        }

        //讀取包頭資訊
        in.readBytes(buf, HEADER_SIZE);

        byte[] req = new byte[buf.readableBytes()];
        buf.readBytes(req);
        String headStr = new String(req, "UTF-8");
        int msgLen = Integer.valueOf(headStr.substring(dstStartPos, dstStopPos).trim());

        // 如發現剩餘位元組不夠包體長度，回滾指標，等待下次解碼
        if (in.readableBytes() < msgLen) {
            in.resetReaderIndex();
            return null;
        }

        //讀取包體資訊
        in.readBytes(buf, msgLen);

        ByteBuf frame = ctx.alloc().buffer(HEADER_SIZE + msgLen);
        frame.writeBytes(buf, 0, HEADER_SIZE + msgLen);
        buf.clear();
        return frame;
    }
}

編碼器：

package com.phei.netty.codec.custom;

import com.lytz.pb.Config;
import com.lytz.pb.ProtocolUtils;
import com.lytz.pb.QstockProtocol.LOFMergeSplitReqt;
import com.lytz.pb.QstockProtocol.StockCreateRedeemReqt;
import com.lytz.pb.QstockProtocol.StockOrderReqt;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToByteEncoder;

/**
 * CustomEncoder.java 說明
 * 
 * @author zhengzy
 * @date 2015年12月24日下午1:33:24
 */
public class CustomEncoder extends MessageToByteEncoder<Message> {

    private static ByteBuf buf = Unpooled.buffer();
    private static byte[] body = null;
    private static byte[] pro = null;

    @Override
    protected void encode(ChannelHandlerContext ctx, Message msg, ByteBuf out) throws Exception {
        switch (msg.getMsgId()) {
        case Config.ID_S_ORDER_REQT:
            StockOrderReqt stockOrderReqt = (StockOrderReqt) msg.getObject();
            body = stockOrderReqt.toByteArray();
            pro = ProtocolUtils.getProtocol(Config.ID_S_ORDER_REQT, body);
            buf.writeBytes(pro);
            out.writeBytes(buf);
            break;
        case Config.ID_S_LOF_UP_REQT:
            LOFMergeSplitReqt mergeSplitReqt = (LOFMergeSplitReqt) msg.getObject();
            body = mergeSplitReqt.toByteArray();
            pro = ProtocolUtils.getProtocol(Config.ID_S_LOF_UP_REQT, body);
            buf.writeBytes(pro);
            out.writeBytes(buf);
            break;
        case Config.ID_S_LOF_CR_REQT:
            StockCreateRedeemReqt stockCreateRedeemReqt = (StockCreateRedeemReqt) msg.getObject();
            body = stockCreateRedeemReqt.toByteArray();
            pro = ProtocolUtils.getProtocol(Config.ID_S_LOF_CR_REQT, body);
            buf.writeBytes(pro);
            out.writeBytes(buf);
            break;

        default:
            break;
        }
        //清除容器中的資料
        buf.clear();
        body = null;
        pro = null;
    }
}

程式碼說明

    /**
     * 找到needle在haystack中的第一個位置，返回位置，沒有返回-1
     * @param haystack
     * @param needle
     * @return
     */
    private static int indexOf(ByteBuf haystack, ByteBuf needle) {
        for (int i = haystack.readerIndex(); i < haystack.writerIndex(); i++) {
            int haystackIndex = i;
            int needleIndex;
            for (needleIndex = 0; needleIndex < needle.capacity(); needleIndex++) {
                if (haystack.getByte(haystackIndex) != needle
                        .getByte(needleIndex)) {
                    break;
                } else {
                    haystackIndex++;
                    if (haystackIndex == haystack.writerIndex()
                            && needleIndex != needle.capacity() - 1) {
                        return -1;
                    }
                }
            }

            if (needleIndex == needle.capacity()) {
                // Found the needle from the haystack!
                return i - haystack.readerIndex();
            }
        }
        return -1;
    }

測試程式碼：

        String bz = "ABCDEFGH";
        String str = "123ABCDEFGH0001123411101007namenamenamename00000000000000000000000000000000      11";
        ByteBuf buf = Unpooled.buffer();
        buf.writeBytes(str.getBytes());
        ByteBuf bzBuf = Unpooled.buffer();
        bzBuf.writeBytes(bz.getBytes());

        System.out.println(indexOf(buf, Unpooled.copiedBuffer(bz.getBytes())));

參考