本文介绍了如何在Qt5中创建/读/写JSon文件的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

Qt5有一个新的JSon解析器,我想使用它。问题是,它不是太清楚什么功能做外行人的术语,如何写它的代码。



我想知道在Qt5中创建Json文件的代码,以及封装是什么意思。

解决方案

示例从文件读取json

 code> / * test.json * / 
{
appDesc:{
description:SomeDescription,
message:SomeMessage
},
appName:{
description:Home,
message:Welcome,
imp:[awesome ,best,good]
}
}


void readJson()
{
QString val;
QFile文件;
file.setFileName(test.json);
file.open(QIODevice :: ReadOnly | QIODevice :: Text);
val = file.readAll();
file.close();
qWarning()<< val;
QJsonDocument d = QJsonDocument :: fromJson(val.toUtf8());
QJsonObject sett2 = d.object();
QJsonValue value = sett2.value(QString(appName));
qWarning()<<值;
QJsonObject item = value.toObject();
qWarning()<< tr(QJsonObject of description:)<<项目;

/ *包含字符串值获取值并转换为字符串* /
qWarning()< tr(QJsonObject [appName] of description:)<<商品描述];
QJsonValue subobj = item [description];
qWarning()<< subobj.toString();

/ * incase数组get数组并转换成字符串* /
qWarning()<< tr(QJsonObject [appName] of value:)< item [imp];
QJsonArray test = item [imp]。toArray();
qWarning()<< test [1] .toString();
}






OUTPUT

  QJsonValue(object,QJsonObject({description:Home,imp:[awesome ,best,good],message:YouTube}))
QJsonObject of description:QJsonObject({description:Home,imp:[awesome, best,good],message:YouTube})
QJsonObject [appName] of description:QJsonValue(string,Home)
Home
QJsonObject [appName] value:QJsonValue(array,QJsonArray([awesome,best,good]))
best
pre>




示例从字符串读取json。 **
** 将json分配给下面的字符串,并使用上面的readJson()函数

  val = 
'{
appDesc:{
description:SomeDescription,
message:SomeMessage
},
appName:{
description:Home,
message:Welcome,
imp:[awesome,best ,good]
}
}';






OUTPUT p>

  QJsonValue(object,QJsonObject({description:Home,imp:[awesome,best good],message:YouTube}))
QJsonObject of description:QJsonObject({description:Home,imp:[awesome,best好的],消息:YouTube})
QJsonObject [appName]的描述:QJsonValue(string,Home)
Home
的值:QJsonValue(array,QJsonArray([awesome,best,good]))
best

Qt5 has a new JSon parser and I want to use it. The problem is that it isn't too clear about what the functions do in layman's terms and how to write code with it. That or I could be reading it wrong.

I want to know the code on creating a Json file in Qt5 and what "encapsulates" mean.

解决方案

Example read json from file

/* test.json */
{
   "appDesc": {
      "description": "SomeDescription",
      "message": "SomeMessage"
   },
   "appName": {
      "description": "Home",
      "message": "Welcome",
      "imp":["awesome","best","good"]
   }
}


void readJson()
   {
      QString val;
      QFile file;
      file.setFileName("test.json");
      file.open(QIODevice::ReadOnly | QIODevice::Text);
      val = file.readAll();
      file.close();
      qWarning() << val;
      QJsonDocument d = QJsonDocument::fromJson(val.toUtf8());
      QJsonObject sett2 = d.object();
      QJsonValue value = sett2.value(QString("appName"));
      qWarning() << value;
      QJsonObject item = value.toObject();
      qWarning() << tr("QJsonObject of description: ") << item;

      /* incase of string value get value and convert into string*/
      qWarning() << tr("QJsonObject[appName] of description: ") << item["description"];
      QJsonValue subobj = item["description"];
      qWarning() << subobj.toString();

      /* incase of array get array and convert into string*/
      qWarning() << tr("QJsonObject[appName] of value: ") << item["imp"];
      QJsonArray test = item["imp"].toArray();
      qWarning() << test[1].toString();
   }


OUTPUT

QJsonValue(object, QJsonObject({"description": "Home","imp": ["awesome","best","good"],"message": "YouTube"}) )
"QJsonObject of description: " QJsonObject({"description": "Home","imp": ["awesome","best","good"],"message": "YouTube"})
"QJsonObject[appName] of description: " QJsonValue(string, "Home")
"Home"
"QJsonObject[appName] of value: " QJsonValue(array, QJsonArray(["awesome","best","good"]) )
"best"


Example read json from string. ****assign json to string as below and use above readJson() function

val =
'  {
       "appDesc": {
          "description": "SomeDescription",
          "message": "SomeMessage"
       },
       "appName": {
          "description": "Home",
          "message": "Welcome",
          "imp":["awesome","best","good"]
       }
    }';


OUTPUT

QJsonValue(object, QJsonObject({"description": "Home","imp": ["awesome","best","good"],"message": "YouTube"}) )
"QJsonObject of description: " QJsonObject({"description": "Home","imp": ["awesome","best","good"],"message": "YouTube"})
"QJsonObject[appName] of description: " QJsonValue(string, "Home")
"Home"
"QJsonObject[appName] of value: " QJsonValue(array, QJsonArray(["awesome","best","good"]) )
"best"

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07-26 15:56