Qt使用QJsonDocument、QJsonObject、QJsonArray解析JSON
Qt使用QJsonDocument、QJsonObject、QJsonArray解析JSON
提问于 2013-11-07 04:32:31
我使用的是Qt5。我正在尝试从json对象获取值。下面是我试图从中获取数据的json对象的样子：
{
"success": true,
"properties": [
{
"ID": 1001,
"PropertyName": "McDonalds",
"key": "00112233445566778899aabbccddeeff"
},
{
"ID": 1002,
"PropertyName": "Burger King",
"key": "10112233445566778899aabbccddeeff"
},
{
"ID": 1003,
"PropertyName": "Taco Bell",
"key": "20112233445566778899aabbccddeeff"
}
]
}如何在Qt中创建包含properties[x].ID、properties[x].PropertyName和properties[x].key的三个数组？
编辑：
使用QScriptEngine时，我尝试了这样做：
QString data = (QString)reply->readAll();
QScriptEngine engine;
QScriptValue result = engine.evaluate(data);
qDebug() << result.toString();调试程序显示"SyntaxError: Parse error“
回答 3
Stack Overflow用户
回答已采纳
发布于 2013-11-07 05:43:05
我想通了：
QStringList propertyNames;
QStringList propertyKeys;
QString strReply = (QString)reply->readAll();
QJsonDocument jsonResponse = QJsonDocument::fromJson(strReply.toUtf8());
QJsonObject jsonObject = jsonResponse.object();
QJsonArray jsonArray = jsonObject["properties"].toArray();
foreach (const QJsonValue & value, jsonArray) {
QJsonObject obj = value.toObject();
propertyNames.append(obj["PropertyName"].toString());
propertyKeys.append(obj["key"].toString());
}Stack Overflow用户
发布于 2018-02-08 04:18:36
这里有一个来自How To Manipulate JSON With C++ and Qt的例子。
// reads a json file from disk to QVariantMap
// originally from http://erickveil.github.io/2016/04/06/How-To-Manipulate-JSON-With-C++-and-Qt.html
bool readJsonFile(std::string file_path, QVariantMap& result)
{
// step 1
QFile file_obj(QString::fromStdString(file_path));
if (!file_obj.open(QIODevice::ReadOnly)) {
std::cout << "Failed to open " << file_path << std::endl;
exit(1);
}
// step 2
QTextStream file_text(&file_obj);
QString json_string;
json_string = file_text.readAll();
file_obj.close();
QByteArray json_bytes = json_string.toLocal8Bit();
// step 3
auto json_doc = QJsonDocument::fromJson(json_bytes);
if (json_doc.isNull()) {
std::cout << "Failed to create JSON doc." << std::endl;
return false;
}
if (!json_doc.isObject()) {
std::cout << "JSON is not an object." << std::endl;
return false;
}
QJsonObject json_obj = json_doc.object();
if (json_obj.isEmpty()) {
std::cout << "JSON object is empty." << std::endl;
return false;
}
// step 4
result = json_obj.toVariantMap();
return true;
}
// writes a QVariantMap to disk
bool writeJsonFile(QVariantMap point_map, std::string file_path)
{
QJsonObject json_obj = QJsonObject::fromVariantMap(point_map);
QJsonDocument json_doc(json_obj);
QString json_string = json_doc.toJson();
QFile save_file(QString::fromStdString(file_path));
if (!save_file.open(QIODevice::WriteOnly)) {
std::cout << "failed to open save file" << std::endl;
return false;
}
save_file.write(json_string.toLocal8Bit());
save_file.close();
return true;
}Stack Overflow用户
发布于 2022-01-06 13:25:45
我使用QT网络向Firebase发出API请求，但由于某种原因，我收到了一个充满数据的响应，但当解析到一个数组时，我收到了null。
void firebaseHandler::parseResponse(const QString &response){
@TODO for some reason sometimes the arrayData is empty
QJsonDocument jsonDocument = QJsonDocument::fromJson(response.toUtf8());
QJsonValue kind = jsonDocument.object().value("kind");
QJsonArray arrayData = jsonDocument.array();
qDebug() << "json response is " << jsonDocument.toJson();
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/19822211
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