[Update]自定义协议并解决TCP粘包/拆包问题

libraries/mogo-telematic/src/main/java/com/mogo/telematic/MogoLengthFrameDecoder.java

@@ -0,0 +1,34 @@
+package com.mogo.telematic;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
+
+public class MogoLengthFrameDecoder extends LengthFieldBasedFrameDecoder {
+    public static final int MAX_FRAME_LENGTH = 3 * 1024 * 1024;
+    // 参考MogoProtocolMsg结构(https://blog.csdn.net/thinking_fioa/article/details/80573483)
+    public static final int LENGTH_FIELD_OFFSET = 4;
+    public static final int LENGTH_FIELD_SIZE = 4;
+
+    public MogoLengthFrameDecoder(int maxFrameLength, int lengthFieldOffset, int lengthFieldLength) {
+        super(maxFrameLength, lengthFieldOffset, lengthFieldLength);
+    }
+
+    @Override
+    protected Object decode(ChannelHandlerContext ctx, ByteBuf in) throws Exception {
+        ByteBuf byteBuf = (ByteBuf) super.decode(ctx, in);
+        if (byteBuf == null) return null;
+        MogoProtocolMsg mogoProtocolMsg = new MogoProtocolMsg();
+        mogoProtocolMsg.setProtocolType(byteBuf.readInt());
+        int length = byteBuf.readInt();
+        mogoProtocolMsg.setBodyLength(length);
+        if (length > 0) {
+            byte[] body = new byte[length];
+            byteBuf.readBytes(body);
+            mogoProtocolMsg.setBody(body);
+        }
+        in.release();
+        return mogoProtocolMsg;
+    }
+
+}