JsonGeneratorExample.ino
Description
This example shows how to generate a JSON document with ArduinoJson.
An online demo of this example is available on wandbox.org.
Source code
#include <ArduinoJson.h>
void setup() {
// Initialize Serial port
Serial.begin(9600);
while (!Serial) continue;
// Allocate the JSON document
//
// Inside the brackets, 200 is the RAM allocated to this document.
// Don't forget to change this value to match your requirement.
// Use arduinojson.org/v6/assistant to compute the capacity.
StaticJsonDocument<200> doc;
// StaticJsonObject allocates memory on the stack, it can be
// replaced by DynamicJsonDocument which allocates in the heap.
//
// DynamicJsonDocument doc(200);
// Add values in the document
//
doc["sensor"] = "gps";
doc["time"] = 1351824120;
// Add an array.
//
JsonArray data = doc.createNestedArray("data");
data.add(48.756080);
data.add(2.302038);
// Generate the minified JSON and send it to the Serial port.
//
serializeJson(doc, Serial);
// The above line prints:
// {"sensor":"gps","time":1351824120,"data":[48.756080,2.302038]}
// Start a new line
Serial.println();
// Generate the prettified JSON and send it to the Serial port.
//
serializeJsonPretty(doc, Serial);
// The above line prints:
// {
// "sensor": "gps",
// "time": 1351824120,
// "data": [
// 48.756080,
// 2.302038
// ]
// }
}
void loop() {
// not used in this example
}
Classes used in this example
Functions used in this example
JsonObject::operator[]
JsonObject::createNestedArray()
JsonArray::add()
serializeJson()
serializeJsonPretty()
Keep learning
The chapter “Serialize with ArduinoJson” of Mastering ArduinoJson is a tutorial to learn how to generate JSON documents with the library. It begins with a simple example, like the one above, and then adds more features like serializing directly to a file or an HTTP request.