任务描述：

项目使用阿里云物联网进行设备和后台服务平台通讯，考虑流量成本，参数多使用HEX类型传输，比字符串省一半字节数。以下分享一个通用的MessagePack解包方法，可以方便解析设备端传输的HEX类型的参数，和其它参数类型
分享一个messagePack的解析网址：https://toolslick.com/conversion/data/messagepack-to-json
废话不多说，直接上代码

Java解包

maven引入依赖包

<dependency>
    <groupId>org.msgpack</groupId>
    <artifactId>msgpack</artifactId>
    <version>0.6.10</version>
</dependency>
<dependency>
    <groupId>org.msgpack</groupId>
    <artifactId>msgpack-core</artifactId>
    <version>0.8.17</version>
</dependency>

实现方法

    /**
     * messagePack数据解包
     * @param v
     * @return
     */
   public static Map<String,Object> unpackValue(byte[] data){
        Map<String,Object> payload = null;
        MessageUnpacker msg = MessagePack.newDefaultUnpacker(data);
        try {
            Value v = msg.unpackValue();
            payload = (Map<String, Object>) getValue(v);
        } catch (Exception e) {
            logger.error("payload 解析出错 " , e);
        }
        return payload;
    }

    public static Object getValue(Value v) {
        Object value = null;
        switch (v.getValueType()) {
            case NIL:
                v.isNilValue(); // true
                break;
            case BOOLEAN:
                boolean b = v.asBooleanValue().getBoolean();
                value = b;
                break;
            case INTEGER:
                IntegerValue iv = v.asIntegerValue();
                if (iv.isInIntRange()) {
                    int i = iv.toInt();
                    value = i;
                } else if (iv.isInLongRange()) {
                    long l = iv.toLong();
                    value = l;
                } else {
                    BigInteger i = iv.toBigInteger();
                    value = i;
                }
                break;
            case FLOAT:
                FloatValue fv = v.asFloatValue();
                float f = fv.toFloat(); // use as float
                double d = fv.toDouble(); // use as double
                value = d;
                break;
            case STRING:
                String _s = v.asStringValue().asString();
                value = _s;
                break;
            case BINARY:
                byte[] mb = v.asBinaryValue().asByteArray();
                value = HexUtils.byte2hexString(mb);
                break;
            case ARRAY:
                ArrayValue a = v.asArrayValue();
                value = a;
                break;
            case MAP:
                Map<String,Object> map = new HashMap<>();
                MapValue m = v.asMapValue();
                for (Value _k : m.map().keySet()) {
                    String _ks = _k.asStringValue().asString();
                    map.put(_ks , getValue(m.map().get(_k)));
                }
                value = map;
                break;
            case EXTENSION:
                ExtensionValue ev = v.asExtensionValue();
                byte extType = ev.getType();
                byte[] extValue = ev.getData();
                break;
        }
        return value;
    }

public static void main(String[] args) throws IOException {

        String unpack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
        byte[] array = HexUtils.hexString2byte(unpack);
        Map<String,Object> pack = unpackValue(array);
        System.out.println(pack);
}

总结

通过上面的方法，可以解析Map类型的MessagePack数据，无论设备端使用HEX字节数组类型，还是使用字符串或者其它数据类型，都可以解包成Map类型，方便后台后续处理，并且可以节省流量。