Arduino處理JSON資料
阿新 • • 發佈:2019-01-04
1.資料
2.JSON總結
JSON的結構
{
"sensor": "gps",
"time": 1351824120,
"data": [
48.75608,
2.302038
]
}
微控制器字串
char json[]="{\"sensor\":\"gps\",\"time\":1351824120,\"data\":[48.756080,2.302038]}";
JSON
物件是一個無序的名稱/值對集合。一個物件以“{”(左括號)開始,“}”(右括號)結束。每個“名稱”後跟一個“:”(冒號);“名稱/值對”之間使用“,”(逗號)分隔。
名稱/值(collection):名稱和值之間使用:隔開,一般的形式是:
{name:value}
值的有序列表(Array):一個或者多個值用,分割槽後,使用[,]括起來就形成了這樣的列表,形如:
[collection, collection]
github上下載開源庫 ArduinoJson-master.zip
庫裡面例子:JsonParserExample
// Copyright Benoit Blanchon 2014-2017
// MIT License
//
// Arduino JSON library
// https://bblanchon.github.io/ArduinoJson/
// If you like this project, please add a star!
#include <ArduinoJson.h>
void setup() {
Serial.begin(9600);
while (!Serial) {
// wait serial port initialization
}
// Memory pool for JSON object tree.
//
// Inside the brackets, 200 is the size of the pool in bytes,
// If the JSON object is more complex, you need to increase that value.
// See https://bblanchon.github.io/ArduinoJson/assistant/
StaticJsonBuffer<200> jsonBuffer;
// StaticJsonBuffer allocates memory on the stack, it can be
// replaced by DynamicJsonBuffer which allocates in the heap.
//
// DynamicJsonBuffer jsonBuffer(200);
// JSON input string.
//
// It's better to use a char[] as shown here.
// If you use a const char* or a String, ArduinoJson will
// have to make a copy of the input in the JsonBuffer.
char json[] =
"{\"sensor\":\"gps\",\"time\":1351824120,\"data\":[48.756080,2.302038]}";
// Root of the object tree.
//
// It's a reference to the JsonObject, the actual bytes are inside the
// JsonBuffer with all the other nodes of the object tree.
// Memory is freed when jsonBuffer goes out of scope.
JsonObject& root = jsonBuffer.parseObject(json);
// Test if parsing succeeds.
if (!root.success()) {
Serial.println("parseObject() failed");
return;
}
// Fetch values.
//
// Most of the time, you can rely on the implicit casts.
// In other case, you can do root["time"].as<long>();
const char* sensor = root["sensor"];
long time = root["time"];
double latitude = root["data"][0];
double longitude = root["data"][1];
// Print values.
Serial.println(sensor);
Serial.println(time);
Serial.println(latitude, 6);
Serial.println(longitude, 6);
}
void loop() {
// not used in this example
}
輸出:
剩下的時間就是自己研究庫檔案了,和自己的專案結合。