ESP32_ChinaDieselHeater_Con.../lib/ArduinoJson/examples/StringExample/StringExample.ino

75 lines
2.5 KiB
Arduino
Raw Normal View History

// ArduinoJson - arduinojson.org
// Copyright Benoit Blanchon 2014-2018
// MIT License
//
// This example shows the different ways you can use String with ArduinoJson.
//
// Use String objects sparingly, because ArduinoJson duplicates them in the
// JsonBuffer. Prefer plain old char[], as they are more efficient in term of
// code size, speed, and memory usage.
#include <ArduinoJson.h>
void setup() {
DynamicJsonBuffer jsonBuffer;
// You can use a String as your JSON input.
// WARNING: the content of the String will be duplicated in the JsonBuffer.
String input =
"{\"sensor\":\"gps\",\"time\":1351824120,\"data\":[48.756080,2.302038]}";
JsonObject& root = jsonBuffer.parseObject(input);
// You can use a String to get an element of a JsonObject
// No duplication is done.
long time = root[String("time")];
// You can use a String to set an element of a JsonObject
// WARNING: the content of the String will be duplicated in the JsonBuffer.
root[String("time")] = time;
// You can get a String from a JsonObject or JsonArray:
// No duplication is done, at least not in the JsonBuffer.
String sensor = root["sensor"];
// Unfortunately, the following doesn't work (issue #118):
// sensor = root["sensor"]; // <- error "ambiguous overload for 'operator='"
// As a workaround, you need to replace by:
sensor = root["sensor"].as<String>();
// You can set a String to a JsonObject or JsonArray:
// WARNING: the content of the String will be duplicated in the JsonBuffer.
root["sensor"] = sensor;
// It works with RawJson too:
root["sensor"] = RawJson(sensor);
// You can also concatenate strings
// WARNING: the content of the String will be duplicated in the JsonBuffer.
root[String("sen") + "sor"] = String("gp") + "s";
// You can compare the content of a JsonObject with a String
if (root["sensor"] == sensor) {
// ...
}
// Lastly, you can print the resulting JSON to a String
String output;
root.printTo(output);
}
void loop() {
// not used in this example
}
// See also
// --------
//
// https://arduinojson.org/ contains the documentation for all the functions
// used above. It also includes an FAQ that will help you solve any problem.
//
// The book "Mastering ArduinoJson" contains a quick C++ course that explains
// how your microcontroller stores strings in memory. On several occasions, it
// shows how you can avoid String in your program.
// Learn more at https://arduinojson.org/book/
// Use the coupon code TWENTY for a 20% discount ❤❤❤❤❤