Question

我的arduino通过TCP接收到一个看起来像这样的json：

{"Order":9,"SenderID":"Master","Params":{"newSolution":"35"}}

我像这样使用#include <ArduinoJson.h>来解析它：

void Connectivity::ProcessNewMessage(char* topic, byte* payload, unsigned int length)
{
    StaticJsonDocument<80> doc;
    DeserializationError err = deserializeJson(doc, payload);
    if (err) {
        Serial.print(F("deserializeJson() failed with code "));
        Serial.println(err.c_str());
    }
    else
    {
        //we get the Order, or 99 if Order is not set. JsonDeserializer never makes exceptions
        //So the only way to know something was wrong is provide unexpected values as Order 99
        int Order = doc["Order"] | 99;
        switch(Order)
        {
            case 9:
            {
               //here I need to access the new solution that is 
               //in the Params.

                const char* serializedParams = (const char*) doc["Params"];
                Serial.println("testing 1:");
                Serial.println(serializedParams);
                Serial.println("++++1");
                DeserializationError err = deserializeJson(doc, serializedParams);
                if (err) {
                    Serial.print(F("deserializeJson() failed with code "));
                    Serial.println(err.c_str());
                }
                else
                {
                   //here the code when everything works
                }
             }
         }

这是我运行东西时得到的输出：

---
internal: Message arrived [master/Arduino] 
{"Order":9,"SenderID":"Master","Params":{"newSolution":"35"}}
testing 1:

++++1
deserializeJson() failed with code IncompleteInput`

您可以在传入的json中看到Params IS，但是在尝试访问它时为空。有任何想法吗？？我是一位经验丰富的C＃编码人员，但是C ++和所有char char * const char mess对我来说很老。。：）

Answer 1

问题是我访问serializedParams的方式。此解决方案有效：

//incoming string is : {"Order":9,"SenderID":"Master","Params":{"newSolution":"35"}}

    StaticJsonDocument<80> doc;
    DeserializationError err = deserializeJson(doc, payload);
    if (err) {
        Serial.print(F("deserializeJson() failed with code "));
        Serial.println(err.c_str());
    }
    else
    {
         const char* Params_newSolution = doc["Params"]["newSolution"];
         // Params_newsOlution contains = "35"
         float alreadyParsed = doc["Params"]["newSolution"];
         // alreadyParsed contains 35.0
    }

在arduino的json中反序列化json

1 个答案: