使用QT遍历Json文档及搜索子对象

关于qt遍历Json文档的代码，整理并记录在这里，方便以后使用。

QT 的版本如下图

 Json文件内容：

{
  "动物": {
    "人": {
      "年龄": 43,
      "电话": [
        "[phone]",
        "[phone]"
      ]
    },

    "狗": {
      "腿": [
        "左前腿",
        "右前腿",
        "左后腿",
        "右后腿"
      ],
      "头": {
        "眼睛": 2,
        "鼻子": 1,
        "耳朵": 2
      }
    }
  }
}

使用QJsonDocument遍历所有对象的输出如下：

"" "根" isObject() 有  1  个子对象 
"    " "动物" isObject() 有  2  个子对象 
"        " "人" isObject() 有  2  个子对象 
"            " "年龄"  isDouble()  43
"            " "电话" isArray() 有  2  个子对象 
"                " ""  isString()  "[phone]"
"                " ""  isString()  "[phone]"
"        " "狗" isObject() 有  2  个子对象 
"            " "头" isObject() 有  3  个子对象 
"                " "眼睛"  isDouble()  2
"                " "耳朵"  isDouble()  2
"                " "鼻子"  isDouble()  1
"            " "腿" isArray() 有  4  个子对象 
"                " ""  isString()  "左前腿"
"                " ""  isString()  "右前腿"
"                " ""  isString()  "左后腿"
"                " ""  isString()  "右后腿"

遍历并输出Json对象的代码：

    //加载Json文件    
    static void LoadJsonFromFile(const QString& jsonfilename,QJsonDocument& jsDoc)
    {
        QFile file(jsonfilename);
        file.open(QIODevice::ReadWrite);
        QByteArray json = file.readAll();
        jsDoc = QJsonDocument::fromJson(json);
    }


    //遍历输出Json对象
    //输入是Json文档
    static void PrintJson(QJsonDocument& jDoc)
    {
        if(jDoc.isObject()) 
        {
            QJsonObject jObject = jDoc.object();  //获得根对象
            PrintJsonObject(jObject,"根");
        }
        else if(jDoc.isArray())
        {
            QJsonArray jArray = jDoc.array();
            PrintJsonArray(jArray,"");
        }
        else
        {
            //空文档
            qDebug() << "空文档";
        }
    }

    //遍历QJsonObject
    static void PrintJsonObject(QJsonObject& obj,const QString& key,int retract=0)
    {
        //输出使用的缩进
        QString tabs = "";
        for(int i=0;i<retract;++i) {tabs+="    ";}

        qDebug() << tabs << key << "isObject() 有 " << obj.size() <<  " 个子对象 ";
        for(const QString& key: obj.keys())  //遍历所有的key
        {
            QJsonValue jvalue = obj[key];
            PrintJsonValue(jvalue,key,retract+1); //打印输出QJsonValue
        }
    }


    //遍历QJsonArray
    static void PrintJsonArray(QJsonArray& arr,const QString& key,int retract=0)
    {
        //输出使用的缩进
        QString tabs = "";
        for(int i=0;i<retract;++i) {tabs+="    ";}

        qDebug() << tabs << key << "isArray() 有 " << arr.size() <<  " 个子对象 ";
        for(QJsonArray::iterator it=arr.begin();it!=arr.end();++it)  //遍历数组内的对象
        {
            QJsonValue jvalue = *it;
            PrintJsonValue(jvalue,"",retract+1); //打印输出QJsonValue
        }
    }

    //打印输出QJsonValue
    static void PrintJsonValue(QJsonValue& jvalue,const QString& key,int retract=0)
    {
        //输出使用的缩进
        QString tabs = "";
        for(int i=0;i<retract;++i) {tabs+="    ";}

        if(jvalue.isArray())
        {
            QJsonArray childArray = jvalue.toArray();
            PrintJsonArray(childArray,key,retract);  //递归调用
        }
        else if(jvalue.isObject())
        {
            QJsonObject childObject = jvalue.toObject();
            PrintJsonObject(childObject,key,retract);  //递归调用
        }
        else if(jvalue.isBool())
        {
            qDebug() << tabs << key << " isBool() " << jvalue.toBool();
        }
        else if(jvalue.isDouble())
        {
            qDebug() << tabs << key << " isDouble() " << jvalue.toDouble();
        }
        else if(jvalue.isString())
        {
            qDebug() << tabs << key << " isString() " << jvalue.toString();
        }
        else if(jvalue.isUndefined())
        {
            qDebug() << tabs << " isUndefined() ";
        }
        else if(jvalue.isNull())
        {
            qDebug() << tabs << " isNull() ";
        }
    }


    //测试代码
    QJsonDocument doc;                        
    ZJsonTools::LoadJsonFromFile(QString("json文件的完整路径名称"),doc);
    ZJsonTools::PrintJson(doc);

搜索Json的代码：

    static bool SearchJsonValue(const QJsonObject& jObject,const QStringList& path,QJsonValue& result)
    {
        QJsonValue jValue = jObject;
        return SearchJsonValue(jValue,path,result);
    }

    static bool SearchJsonValue(const QJsonValue& jValue,const QStringList& path,QJsonValue& result)
    {
        result = jValue;
        for(int i=0;i<path.length();++i)
        {
            result = result[path[i]];
            if(result.isNull() || result.isUndefined())
            {
                return false;
            }
        }
        return true;
    }


    //测试代码
    QStringList path = {"动物","狗","头","鼻子"};
    QJsonObject jObject = doc.object();
    QJsonValue jObj;
    if(ZJsonTools::SearchJsonValue(jObject,path,jObj))
    {
        qDebug()<< " 狗鼻子的数量： " << jObj.toInt();
    }
    else
    {
        qDebug()<< "  未找到 ";
    }

搜索Json测试代码输出：

 狗鼻子的数量：  1

完整的ZJsonTools类代码：

#include <QJsonDocument>
#include <QJsonObject>
#include <QJsonValue>
#include <QJsonArray>
#include <QString>
#include <QFile>
#include <QList>
#include <QDebug>

class ZJsonTools final
{
private:
    ZJsonTools();

public:
    static void LoadJsonFromFile(const QString& jsonfilename,QJsonDocument& jsDoc)
    {
        QFile file(jsonfilename);
        file.open(QIODevice::ReadWrite);
        QByteArray json = file.readAll();
        jsDoc = QJsonDocument::fromJson(json);
    }

    static void PrintJson(QJsonDocument& jDoc)
    {
        if(jDoc.isObject())
        {
            QJsonObject jObject = jDoc.object();
            PrintJsonObject(jObject,"根");
        }
        else if(jDoc.isArray())
        {
            QJsonArray jArray = jDoc.array();
            PrintJsonArray(jArray,"");
        }
        else
        {
            //空文档
            qDebug() << "空文档";
        }
    }

    static bool SearchJsonValue(const QJsonObject& jObject,const QStringList& path,QJsonValue& result)
    {
        QJsonValue jValue = jObject;
        return SearchJsonValue(jValue,path,result);
    }

    static bool SearchJsonValue(const QJsonValue& jValue,const QStringList& path,QJsonValue& result)
    {
        result = jValue;
        for(int i=0;i<path.length();++i)
        {
            result = result[path[i]];
            if(result.isNull() || result.isUndefined())
            {
                return false;
            }
        }
        return true;
    }

private:
    static void PrintJsonObject(QJsonObject& obj,const QString& key,int retract=0)
    {
        //输出使用的缩进
        QString tabs = "";
        for(int i=0;i<retract;++i) {tabs+="    ";}

        qDebug() << tabs << key << "isObject() 有 " << obj.size() <<  " 个子对象 ";
        for(const QString& key: obj.keys())
        {
            QJsonValue jvalue = obj[key];
            PrintJsonValue(jvalue,key,retract+1);
        }

    }

    static void PrintJsonArray(QJsonArray& arr,const QString& key,int retract=0)
    {
        //输出使用的缩进
        QString tabs = "";
        for(int i=0;i<retract;++i) {tabs+="    ";}

        qDebug() << tabs << key << "isArray() 有 " << arr.size() <<  " 个子对象 ";
        for(QJsonArray::iterator it=arr.begin();it!=arr.end();++it)
        {
            QJsonValue jvalue = *it;
            PrintJsonValue(jvalue,"",retract+1);
        }
    }

    static void PrintJsonValue(QJsonValue& jvalue,const QString& key,int retract=0)
    {
        //输出使用的缩进
        QString tabs = "";
        for(int i=0;i<retract;++i) {tabs+="    ";}

        if(jvalue.isArray())
        {
            QJsonArray childArray = jvalue.toArray();
            PrintJsonArray(childArray,key,retract);
        }
        else if(jvalue.isObject())
        {
            QJsonObject childObject = jvalue.toObject();
            PrintJsonObject(childObject,key,retract);
        }
        else if(jvalue.isBool())
        {
            qDebug() << tabs << key << " isBool() " << jvalue.toBool();
        }
        else if(jvalue.isDouble())
        {
            qDebug() << tabs << key << " isDouble() " << jvalue.toDouble();
        }
        else if(jvalue.isString())
        {
            qDebug() << tabs << key << " isString() " << jvalue.toString();
        }
        else if(jvalue.isUndefined())
        {
            qDebug() << tabs << " isUndefined() ";
        }
        else if(jvalue.isNull())
        {
            qDebug() << tabs << " isNull() ";
        }
    }

};