Netty中序列化的作用及自定义协议详解

public class SerializeTestVO implements Serializable {
    private Integer id;
    private String name;
    private Integer age;
    private Integer sex;
    private Integer bodyWeight;
    private Integer height;
    private String school;
    //Set、get方法省略
}

public static void main(String[] args) throws IOException {
        // 普普通通的实体类
        SerializeTestVO serializeTestVO = new SerializeTestVO();
        serializeTestVO.setAge(18);
        serializeTestVO.setBodyWeight(120);
        serializeTestVO.setHeight(180);
        serializeTestVO.setId(10000);
        serializeTestVO.setName("张三");
        serializeTestVO.setSchool("XXXXXXXXXXXX");
        // JDK序列化
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        ObjectOutputStream objectOutputStream = new ObjectOutputStream(byteArrayOutputStream);
        objectOutputStream.writeObject(serializeTestVO);
        objectOutputStream.flush();
        objectOutputStream.close();
        System.out.println("JDK 序列化大小: "+(byteArrayOutputStream.toByteArray().length));
        byteArrayOutputStream.close();
        //JSON序列化
        System.out.println("JSON 序列化大小: " + JSON.toJSONString(serializeTestVO).getBytes().length);
}

public static void main(String[] args) throws IOException {
        SerializeTestVO serializeTestVO = new SerializeTestVO();
        serializeTestVO.setAge(18);
        serializeTestVO.setBodyWeight(120);
        serializeTestVO.setHeight(180);
        serializeTestVO.setId(10000);
        serializeTestVO.setName("张三");
        serializeTestVO.setSchool("XXXXXXXXXXXX");
        long start = System.currentTimeMillis();
        for (int i = 0; i < 3000000; i++) {
            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
            ObjectOutputStream objectOutputStream = new ObjectOutputStream(byteArrayOutputStream);
            objectOutputStream.writeObject(serializeTestVO);
            objectOutputStream.flush();
            objectOutputStream.close();
            byte[] bytes = byteArrayOutputStream.toByteArray();
            byteArrayOutputStream.close();
        }
        System.out.println("JDK 序列化耗时： " + (System.currentTimeMillis() - start));
        long start1 = System.currentTimeMillis();
        for (int i = 0; i < 3000000; i++) {
            byte[] bytes = JSON.toJSONString(serializeTestVO).getBytes();
        }
        System.out.println("JSON 序列化耗时： " + (System.currentTimeMillis() - start1));
    }

@Data
public class NettyMsg {
    private NettyMsgHead msgHead=new NettyMsgHead();
    private NettyBody nettyBody;
    public NettyMsg(ServiceCodeEnum codeEnum, Object msg){
        this.nettyBody=new NettyBody(codeEnum, msg);
    }
}
@Data
public class NettyMsgHead {
    // 开始标识
    private short startSign = (short) 0xFFFF;
    // 时间戳
    private final int timeStamp;
    public NettyMsgHead(){
        this.timeStamp=(int)(DateUtil.current() / 1000);
    }
}
@Data
public class NettyBody {
    // 通信凭证
    private String token;
    // 消息ID
    private String msgId;
    // 消息类型
    private short msgType;
    // 消息 这里序列化采用JSON序列化
    // 所以这个msg可以是实体类的msg 两端通过消息类型来判断实体类类型
    private String msg;
    public NettyBody(){
    }
    public NettyBody(ServiceCodeEnum codeEnum,Object msg){
        this.token=""; // 鉴权使用
        this.msgId=""; // 拓展使用
        this.msgType=codeEnum.getCode();
        this.msg= JSON.toJSONString(msg);
    }
}

@JsonFormat(shape = JsonFormat.Shape.OBJECT)
public enum ServiceCodeEnum {
    TEST_TYPE((short) 0xFFF1, "测试");


    private final short code;
    private final String desc;

    ServiceCodeEnum(short code, String desc) {
        this.code = code;
        this.desc = desc;
    }
    
    public short getCode() {
        return code;
    }

}

public class MyNettyEncoder extends MessageToByteEncoder<NettyMsg> {
    @Override
    protected void encode(ChannelHandlerContext channelHandlerContext, NettyMsg msg, ByteBuf out) throws Exception {
        // 写入开头的标志
        out.writeShort(msg.getMsgHead().getStartSign());
        // 写入秒时间戳
        out.writeInt(msg.getMsgHead().getTimeStamp());
        byte[] bytes = JSON.toJSON(msg.getNettyBody()).toString().getBytes();
        // 写入消息长度
        out.writeInt(bytes.length);
        // 写入消息主体
        out.writeBytes(bytes);
    }
}

public class MyNettyDecoder extends LengthFieldBasedFrameDecoder {
    // 开始标记
    private final short HEAD_START = (short) 0xFFFF;
    public MyNettyDecoder(int maxFrameLength, int lengthFieldOffset, int lengthFieldLength) {
        super(maxFrameLength, lengthFieldOffset, lengthFieldLength);
    }
    public MyNettyDecoder(int maxFrameLength, int lengthFieldOffset, int lengthFieldLength, int lengthAdjustment, int initialBytesToStrip) {
        super(maxFrameLength, lengthFieldOffset, lengthFieldLength, lengthAdjustment, initialBytesToStrip);
    }
    public MyNettyDecoder(int maxFrameLength, int lengthFieldOffset, int lengthFieldLength, int lengthAdjustment, int initialBytesToStrip, boolean failFast) {
        super(maxFrameLength, lengthFieldOffset, lengthFieldLength, lengthAdjustment, initialBytesToStrip, failFast);
    }
    public MyNettyDecoder(ByteOrder byteOrder, int maxFrameLength, int lengthFieldOffset, int lengthFieldLength, int lengthAdjustment, int initialBytesToStrip, boolean failFast) {
        super(byteOrder, maxFrameLength, lengthFieldOffset, lengthFieldLength, lengthAdjustment, initialBytesToStrip, failFast);
    }
    @Override
    protected Object decode(ChannelHandlerContext ctx, ByteBuf in) throws Exception {
        // 经过父解码器的处理 我们就不需要在考虑沾包和半包了
        // 当然，想要自己处理沾包和半包问题也不是不可以
        ByteBuf decode = (ByteBuf) super.decode(ctx, in);
        if (decode == null) {
            return null;
        }
        // 开始标志校验  开始标志不匹配直接 过滤此条消息
        short startIndex = decode.readShort();
        if (startIndex != HEAD_START) {
            return null;
        }
        // 时间戳
        int timeIndex = decode.readInt();
        // 消息体长度
        int lenOfBody = decode.readInt();
        // 读取消息
        byte[] msgByte = new byte[lenOfBody];
        decode.readBytes(msgByte);
        String msgContent = new String(msgByte);
        // 将消息转成实体类 传递给下面的数据处理器
        return JSON.parseObject(msgContent, NettyBody.class);
    }
}