Qt平台下使用QJson解析和构建JSON字符串

心已赠人 2022-09-14 13:28 444阅读 0赞

本文转载自：[Qt平台下使用QJson解析和构建JSON字符串 - 知乎][Qt_QJson_JSON_ -]

原作者总结的很好，受益很大，学习到了

开发平台基于Qt 5.8 Windows。

示例的JSON字符串和上一篇使用的是一样的。

JSON解析示例包括：

*  和风天气实时数据
 *  心知天气实时数据
 *  心知天气3天预报数据
 *  城市空气质量AQI信息
 *  全国油价信息
 *  北京时间等。

JSON的构建：

*  简单的键值对
 *  JSON对象作为键的值
 *  JSON数组
 *  JSON数组的嵌套

### QJson解析JSON示例 ###

JSON的解析要对照JSON字符串来理解，关于JSON字符串的介绍，可以参考[JSON简介][JSON]

首先，解析和构建都要包含如下头文件：

#include <QJsonDocument>
    #include <QJsonObject>
    #include <QJsonArray>

### 示例字符串1：和风天气实时数据 ###

这个JSON字符串中HeWeather6键的值是一个数组，数组内只有1个JSON对象，这个对象里又嵌套了几个JSON对象。

{
        "HeWeather6": [{
            "basic": {
                "cid": "CN101010700",
                "location": "昌平",
                "parent_city": "北京",
                "admin_area": "北京",
                "cnty": "中国",
                "lat": "40.21808624",
                "lon": "116.23590851",
                "tz": "+8.00"
            },
            "update": {
                "loc": "2019-07-20 10:21",
                "utc": "2019-07-20 02:21"
            },
            "status": "ok",
            "now": {
                "cloud": "96",
                "cond_code": "104",
                "cond_txt": "阴",
                "fl": "28",
                "hum": "86",
                "pcpn": "0.0",
                "pres": "995",
                "tmp": "25",
                "vis": "4",
                "wind_deg": "100",
                "wind_dir": "东风",
                "wind_sc": "1",
                "wind_spd": "4"
            }
        }]
    }

字符串1解析函数

主要是JSON的多层嵌套的解析。

int Parse_HeWeather_Now_Json(void)
    {
        QJsonParseError err_rpt;
        QJsonDocument  root_Doc = QJsonDocument::fromJson(he_now_json, &err_rpt);//字符串格式化为JSON
    
        if(err_rpt.error != QJsonParseError::NoError)
        {
            qDebug() << "JSON格式错误";
            return -1;
        }
        else    //JSON格式正确
        {
            //        qDebug() << "JSON格式正确：\n" << root_Doc;
    
            QJsonObject root_Obj = root_Doc.object();
            QJsonValue weather_Value = root_Obj.value("HeWeather6");    //HeWeather6键的值，是一个数组
            if(weather_Value.isArray()) //可省略
            {
                QJsonObject weather_Obj = weather_Value.toArray().at(0).toObject();   //HeWeather6数组就含有一个元素0
    
                /* basic键信息 */
                QJsonObject basic_Obj = weather_Obj.value("basic").toObject();
                QString cid = basic_Obj.value("cid").toString();
                QString location = basic_Obj.value("location").toString();
                QString parent_city = basic_Obj.value("parent_city").toString();
                QString cnty = basic_Obj.value("cnty").toString();
                QString lat = basic_Obj.value("lat").toString();
                QString lon = basic_Obj.value("lon").toString();
                QString basic_info = cid + " " + parent_city + " " + cnty + " " + lat + " " + lon;
                qDebug() << basic_info;
    
                /* update键信息 */
                QJsonObject update_Obj = weather_Obj.value("update").toObject();
                QString loc = "当地时间:" + update_Obj.value("loc").toString();   //当地时间
                QString utc = "UTC时间:" + update_Obj.value("utc").toString();   //UTC时间
                QString status = "解析状态:" + weather_Obj.value("status").toString();    //"ok"
                qDebug() << loc + " " + utc + " " + status;
    
                /* now键信息*/
                QJsonObject now_Obj = weather_Obj.value("now").toObject();
                QString cond_txt = "白天天气:" + now_Obj.value("cond_txt").toString();
                QString hum = "湿度:" + now_Obj.value("hum").toString();
                QString tmp = "温度:" + now_Obj.value("tmp").toString();
                QString wind_dir = "风向:" +  now_Obj.value("wind_dir").toString();
                QString wind_sc = "风级:" + now_Obj.value("wind_sc").toString();
                qDebug() << cond_txt + " " + hum + " " + tmp + " " + wind_dir + " " + wind_sc;
            }
            qDebug() << "解析完成!";
        }
        return 0;
    }

### 示例字符串2：心知天气实时数据 ###

这个字符串和上面那个一样，都是数组元素是JSON对象，对象的值又是一个JSON对象。

{
        "results": [{
            "location": {
                "id": "WX4FBXXFKE4F",
                "name": "北京",
                "country": "CN",
                "path": "北京,北京,中国",
                "timezone": "Asia/Shanghai",
                "timezone_offset": "+08:00"
            },
            "now": {
                "text": "晴",
                "code": "1",
                "temperature": "-7"
            },
            "last_update": "2018-12-06T22:05:00+08:00"
        }]
    }

字符串2解析函数

int Parse_Seniverse_Now_Json(void)
    {
        QJsonParseError err_rpt;
        QJsonDocument  root_Doc = QJsonDocument::fromJson(seniverse_now_json, &err_rpt);//字符串格式化为JSON
        if(err_rpt.error != QJsonParseError::NoError)
        {
            qDebug() << "JSON格式错误";
            return -1;
        }
        else    //JSON格式正确
        {
            //        qDebug() << "JSON格式正确：\n" << root_Doc;
            QJsonObject root_Obj = root_Doc.object();
            QJsonValue result_Value = root_Obj.value("results");
            if(result_Value.isArray())
            {
                QJsonObject result_Obj = result_Value.toArray().at(0).toObject();
    
                QString last_update = result_Obj.value("last_update").toString();
                qDebug() << last_update;
    
                /* location键的值 */
                QJsonObject location_Obj = result_Obj.value("location").toObject();
                QString id = location_Obj.value("id").toString();
                QString name = location_Obj.value("name").toString();
                QString timezone = location_Obj.value("timezone").toString();
                QString path = location_Obj.value("path").toString();
                QString loc_str = id + " " + name + " " + timezone + " " + path ;
                qDebug() << loc_str;
    
                /* now键 */
                QJsonObject now_Obj = result_Obj.value("now").toObject();
                QString code = "天气代码: " + now_Obj.value("code").toString();
                QString temperature = "当前温度：" + now_Obj.value("temperature").toString();
                QString text = "天气：" + now_Obj.value("text").toString();
                qDebug() << code << temperature << text;
            }
        }
        return 0;
    }

### 示例字符串3：心知3天天气预报数据 ###

{
        "results": [{
            "location": {
                "id": "WS10730EM8EV",
                "name": "深圳",
                "country": "CN",
                "path": "深圳,深圳,广东,中国",
                "timezone": "Asia/Shanghai",
                "timezone_offset": "+08:00"
            },
            "daily": [{
                "date": "2018-12-06",
                "text_day": "阴",
                "code_day": "9",
                "text_night": "阴",
                "code_night": "9",
                "high": "25",
                "low": "16",
                "precip": "",
                "wind_direction": "无持续风向",
                "wind_direction_degree": "",
                "wind_speed": "10",
                "wind_scale": "2"
            }, {
                "date": "2018-12-07",
                "text_day": "阴",
                "code_day": "9",
                "text_night": "小雨",
                "code_night": "13",
                "high": "20",
                "low": "15",
                "precip": "",
                "wind_direction": "北",
                "wind_direction_degree": "0",
                "wind_speed": "15",
                "wind_scale": "3"
            }, {
                "date": "2018-12-08",
                "text_day": "小雨",
                "code_day": "13",
                "text_night": "小雨",
                "code_night": "13",
                "high": "17",
                "low": "12",
                "precip": "",
                "wind_direction": "东北",
                "wind_direction_degree": "45",
                "wind_speed": "15",
                "wind_scale": "3"
            }],
            "last_update": "2018-12-06T18:00:00+08:00"
        }]
    }

字符串3解析函数

int Parse_Seniverse_Forecast_Json(void)
    {
        QJsonParseError err_rpt;
        QJsonDocument  root_Doc = QJsonDocument::fromJson(seniverse_forcast_json, &err_rpt);//字符串格式化为JSON
        if(err_rpt.error != QJsonParseError::NoError)
        {
            qDebug() << "JSON格式错误";
            return -1;
        }
        else    //JSON格式正确
        {
            //        qDebug() << "JSON格式正确：\n" << root_Doc;
            QJsonObject root_Obj = root_Doc.object();
            QJsonValue result_Value = root_Obj.value("results");
            if(result_Value.isArray())
            {
                QJsonObject result_Obj = result_Value.toArray().at(0).toObject();
    
                QString last_update = result_Obj.value("last_update").toString();
                qDebug() << last_update;
                /* location键的值 */
                QJsonObject location_Obj = result_Obj.value("location").toObject();
                QString id = location_Obj.value("id").toString();
                QString name = location_Obj.value("name").toString();
                QString timezone = location_Obj.value("timezone").toString();
                QString path = location_Obj.value("path").toString();
                QString loc_str = id + " " + name + " " + timezone + " " + path ;
                qDebug() << loc_str;
    
                /* daily预报天气3天，数组元素3个*/
                QJsonValue daily_Vaule = result_Obj.value("daily");
                if(daily_Vaule.isArray())
                {
                    for(int idx = 0; idx <= 2; idx++)
                    {
                        QJsonObject daily_Obj = daily_Vaule.toArray().at(idx).toObject();
                        QString date = " 日期：" + daily_Obj.value("date").toString();
                        QString text_day =" 白天天气：" +  daily_Obj.value("text_day").toString();
                        QString high = " 最高温度：" + daily_Obj.value("high").toString();
                        QString low = " 最低温度：" + daily_Obj.value("low").toString();
                        QString wind_direction = " 风向：" + daily_Obj.value("wind_direction").toString();
                        QString wind_scale = " 风级：" + daily_Obj.value("wind_scale").toString();
                        qDebug() << date + text_day + high + low + wind_direction + wind_scale;
                    }
                }
            }
        }
        return 0;
    }

### 示例字符串4：空气AQI质量指数 ###

包含10个元素的数组。

{
        "status": "0",
        "citye": "changchun",
        "city": "长春",
        "citycode": "101060101",
        "aqi": "50",
        "data": [{
            "add": "长春",
            "aqi": "50",
            "pm25": "22",
            "per": "优",
            "lv": "1"
        }, {
            "add": "食品厂",
            "aqi": "54",
            "pm25": "18",
            "per": "良",
            "lv": "2"
        }, {
            "add": "客车厂",
            "aqi": "52",
            "pm25": "20",
            "per": "良",
            "lv": "2"
        }, {
            "add": "邮电学院",
            "aqi": "35",
            "pm25": "24",
            "per": "优",
            "lv": "1"
        }, {
            "add": "劳动公园",
            "aqi": "45",
            "pm25": "19",
            "per": "优",
            "lv": "1"
        }, {
            "add": "园林处",
            "aqi": "45",
            "pm25": "21",
            "per": "优",
            "lv": "1"
        }, {
            "add": "净月潭",
            "aqi": "46",
            "pm25": "30",
            "per": "优",
            "lv": "1"
        }, {
            "add": "甩湾子",
            "aqi": "51",
            "pm25": "24",
            "per": "良",
            "lv": "2"
        }, {
            "add": "经开区环卫处",
            "aqi": "48",
            "pm25": "25",
            "per": "优",
            "lv": "1"
        }, {
            "add": "高新区管委会",
            "aqi": "51",
            "pm25": "16",
            "per": "良",
            "lv": "2"
        }, {
            "add": "岱山公园",
            "aqi": "49",
            "pm25": "19",
            "per": "优",
            "lv": "1"
        }]
    }

字符串4解析函数

int Parse_AQI_Json(void)
    {
        QJsonParseError err_rpt;
        QJsonDocument  root_Doc = QJsonDocument::fromJson(AQI_json, &err_rpt);//字符串格式化为JSON
        if(err_rpt.error != QJsonParseError::NoError)
        {
            qDebug() << "JSON格式错误";
            return -1;
        }
        else    //JSON格式正确
        {
            //        qDebug() << "JSON格式正确：\n" << root_Doc;
            QJsonObject root_Obj = root_Doc.object();
    
            QString city = root_Obj.value("city").toString();
            QString citycode = root_Obj.value("citycode").toString();
            QString citye = root_Obj.value("citye").toString();
            QString status = root_Obj.value("status").toString();
            qDebug() << city + " " + citycode + " " + citye + " " + status;
    
            /* data键 */
            QJsonValue data_Vaule = root_Obj.value("data");
            if(data_Vaule.isArray())
            {
                for(int idx = 0; idx <= 10; idx++)
                {
                    QJsonObject data_Obj = data_Vaule.toArray().at(idx).toObject();
                    QString add = "地址：" + data_Obj.value("add").toString();
                    QString aqi = " AQI：" + data_Obj.value("aqi").toString();
                    QString lv = " 空气质量等级：" + data_Obj.value("lv").toString();
                    QString per = " 空气质量：" + data_Obj.value("per").toString();
                    QString pm25 = " PM2.5等级：" + data_Obj.value("pm25").toString();
                    qDebug() << add + aqi + lv + per + pm25;
                }
            }
        }
        return 0;
    }

### 示例字符串5：北京标准时间 ###

比较简单一个JSON对象

{
        "success": "1",
        "result": {
            "timestamp": "1542456793",
            "datetime_1": "2018-11-17 20:13:13",
            "datetime_2": "2018年11月17日 20时13分13秒",
            "week_1": "6",
            "week_2": "星期六",
            "week_3": "周六",
            "week_4": "Saturday"
        }
    }

字符串5解析函数

int Parse_BJTime_Json(void)
    {
        QJsonParseError err_rpt;
        QJsonDocument  root_Doc = QJsonDocument::fromJson(bj_time_json, &err_rpt);//字符串格式化为JSON
        if(err_rpt.error != QJsonParseError::NoError)
        {
            qDebug() << "JSON格式错误";
            return -1;
        }
        else    //JSON格式正确
        {
            //        qDebug() << "JSON格式正确：\n" << root_Doc;
            QJsonObject root_Obj = root_Doc.object();
    
            QString success = root_Obj.value("success").toString();
            /* result键 */
            QJsonObject result_Obj = root_Obj.value("result").toObject();
            QString datetime_1 = result_Obj.value("datetime_1").toString();
            QString datetime_2 = result_Obj.value("datetime_2").toString();
            QString timestamp = result_Obj.value("timestamp").toString();
            QString week_1 = result_Obj.value("week_1").toString();
            QString week_2 = result_Obj.value("week_2").toString();
            QString week_3 = result_Obj.value("week_3").toString();
            QString week_4 = result_Obj.value("week_4").toString();
            qDebug() << datetime_1 << datetime_2;
            qDebug() << week_1 << week_2 << week_3 << week_4;
        }
        return 0;
    }

### 示例字符串6：全国城市油价信息 ###

这种格式的字符串也是标准的JSON字符串，\[\]表示数组，这个数组内包含了5个字符串：

["北京", "6.78", "7.21", "8.19", "6.45"]

但是这种不是，\{\}表示对象：

{"北京", "6.78", "7.21", "8.19", "6.45"}

一个数组内包含5个元素，每个元素又是一个数组，每个数组又包含5个字符串，属于数组的嵌套：

{
        "status": "0",
        "msg": "全国各省份汽柴油价格信息",
        "update": "2019-07-21",
        "data": [
            ["地区", "92号", "95号", "98号", "0号柴油"],
            ["北京", "6.78", "7.21", "8.19", "6.45"],
            ["上海", "6.74", "7.17", "7.87", "6.39"],
            ["江苏", "6.75", "7.18", "8.06", "6.37"],
            ["天津", "6.77", "7.15", "8.07", "6.41"]
        ],
        "About": "wcc",
        "Home": "www.wangchaochao.top"
    }

字符串6解析函数

//解析数组嵌套的JSON字符串
    int Parse_Oil_Price_Json(void)
    {
        QJsonParseError err_rpt;
        QJsonDocument  root_Doc = QJsonDocument::fromJson(oil_price_json, &err_rpt);//字符串格式化为JSON
        if(err_rpt.error != QJsonParseError::NoError)
        {
            qDebug() << "JSON格式错误";
            return -1;
        }
        else    //JSON格式正确
        {
            //        qDebug() << "JSON格式正确：\n" << root_Doc;
            QJsonObject root_Obj = root_Doc.object();
    
            QString msg = root_Obj.value("msg").toString();
            QString update = root_Obj.value("update").toString();
            QString status = root_Obj.value("status").toString();
            QString About = root_Obj.value("About").toString();
            QString Home = root_Obj.value("Home").toString();
            qDebug() << msg << update << status << About << Home;
    
            /* data键解析 */
            QJsonValue data_Value = root_Obj.value("data");
            if(data_Value.isArray())    //数组中包含5个数组，每个数组5个字符串元素
            {
                for(int idx = 0; idx <= 4; idx++)
                {
                    QJsonValue price_Obj = data_Value.toArray().at(idx);
                    if(price_Obj.isArray())
                    {
                        QString str1 = price_Obj.toArray().at(0).toString();// 每个元素是一个字符串
                        QString str2 = price_Obj.toArray().at(1).toString();
                        QString str3 = price_Obj.toArray().at(2).toString();
                        QString str4 = price_Obj.toArray().at(3).toString();
                        QString str5 = price_Obj.toArray().at(4).toString();
                        qDebug() << str1 << str2 << str3 << str4 << str5 ;
                    }
                }
            }
        }
        return 0;
    }

### QJson构建JSON示例 ###

### 1.构建一个简单的键值对JSON ###

void Create_Simple_JSON(void)
    {
    
        //创建JSON对象
        QJsonObject root_Obj;
        //添加键值对，值的类型自动识别，顺序不可自定义
        root_Obj.insert("CSDN", "https://blog.csdn.net/whik1194");
        root_Obj.insert("cnblogs", "https://home.cnblogs.com/u/whik/");
        root_Obj.insert("Github", "https://github.com/whik/");
        root_Obj.insert("Blog", "https://www.wangchaochao.top/");
        root_Obj.insert("status", 1);
        root_Obj.insert("enable", true);
        root_Obj.insert("update_time", "20190723");
    
        //创建Json文档
        QJsonDocument root_Doc;
        root_Doc.setObject(root_Obj);
        QByteArray root_str = root_Doc.toJson(QJsonDocument::Compact);  //紧凑格式
    //    QByteArray root_str = root_Doc.toJson(QJsonDocument::Indented);   //标准JSON格式    QString strJson(root_str);
        QString strJson(root_str);
        qDebug() << strJson;
    }

输出结果

{
        "Blog": "https://www.wangchaochao.top/",
        "CSDN": "https://blog.csdn.net/whik1194",
        "Github": "https://github.com/whik/",
        "cnblogs": "https://home.cnblogs.com/u/whik/",
        "enable": true,
        "status": 1,
        "update_time": "20190723"
    }

### 2.构建北京时间JSON字符串 ###

void Create_BJTime_JSON(void)
    {
        QJsonObject result_Obj;
        result_Obj.insert("timestamp", "ok");
        result_Obj.insert("datetime_1", "2019-07-21 10:46:57");
        result_Obj.insert("datetime_2", "2019年07月21日 10时46分57秒");
        result_Obj.insert("week_1", "0");
        result_Obj.insert("week_2", "星期日");
        result_Obj.insert("week_3", "周日");
        result_Obj.insert("week_4", "Sunday");
    
        QJsonObject root_Obj;
        //添加键值对，值的类型自动识别，顺序不可自定义
        root_Obj.insert("status", "success");
        root_Obj.insert("Blog", "www.wangchaochao.top");
        root_Obj.insert("result", result_Obj);
    
        //创建Json文档
        QJsonDocument root_Doc;
        root_Doc.setObject(root_Obj);
        QByteArray root_str = root_Doc.toJson(QJsonDocument::Compact);  //紧凑格式
    //    QByteArray root_str = root_Doc.toJson(QJsonDocument::Indented);   //标准JSON格式
    //    qDebug() << root_str; //中文输出乱码
        QString strJson(root_str);
        qDebug() << strJson;
    }

输出结果

{
        "status": "success",
        "result": {
            "timestamp": "ok",
            "datetime_1": "2019-07-21 10:46:57",
            "datetime_2": "2019年07月21日 10时46分57秒",
            "week_1": "0",
            "week_2": "星期日",
            "week_3": "周日",
            "week_4": "Sunday"
        },
        "Blog": "www.wangchaochao.top"
    }

### 3.构建字符串数组 ###

void Create_Array_Str_JSON(void)
    {
        QJsonArray root_Arr;
    
        root_Arr.insert(0, "Sunday");
        root_Arr.insert(1, "Monday");
        root_Arr.insert(2, "Tuesday");
        root_Arr.insert(3, "Wednesday");
        root_Arr.insert(4, "Thursday");
        root_Arr.insert(5, "Friday");
        root_Arr.insert(6, "Saturday");
    
        //创建Json文档
        QJsonDocument root_Doc;
        root_Doc.setArray(root_Arr);
        QByteArray root_str = root_Doc.toJson(QJsonDocument::Compact);  //紧凑格式
    //    QByteArray root_str = root_Doc.toJson(QJsonDocument::Indented);   //标准JSON格式
    //    qDebug() << root_str; //中文输出乱码
        QString strJson(root_str);
        qDebug() << strJson;
    }

输出结果

["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"]

### 4.构建数组JSON ###

void Create_Array_JSON(void)
    {
        QJsonObject day0_Obj;
        QJsonObject day1_Obj;
        QJsonObject day2_Obj;
    
        day0_Obj.insert("date", "2019-07-21");
        day0_Obj.insert("cond_txt", "多云");
        day0_Obj.insert("cond_code", "101");
        day0_Obj.insert("hum", "23");
        day0_Obj.insert("tmp_H", "31");
        day0_Obj.insert("tmp_L", "25");
    
        day1_Obj.insert("date", "2019-07-21");
        day1_Obj.insert("cond_txt", "阵雨");
        day1_Obj.insert("cond_code", "107");
        day1_Obj.insert("hum", "44");
        day1_Obj.insert("tmp_H", "30");
        day1_Obj.insert("tmp_L", "26");
    
        day2_Obj.insert("date", "2019-07-22");
        day2_Obj.insert("cond_txt", "晴");
        day2_Obj.insert("cond_code", "100");
        day2_Obj.insert("hum", "20");
        day2_Obj.insert("tmp_H", "33");
        day2_Obj.insert("tmp_L", "26");
    
        QJsonArray weather_Arr;
        weather_Arr.insert(0, day0_Obj);
        weather_Arr.insert(1, day1_Obj);
        weather_Arr.insert(2, day2_Obj);
    
        QJsonObject root_Obj;
        root_Obj.insert("status", "ok");
        root_Obj.insert("update", "2019-07-21 11:00");
        root_Obj.insert("Blog", "www.wangchaochao.top");
        root_Obj.insert("weather", weather_Arr);    //数组作为weather键的值
    
        //创建Json文档
        QJsonDocument root_Doc;
        root_Doc.setObject(root_Obj);
        QByteArray root_str = root_Doc.toJson(QJsonDocument::Compact);  //紧凑格式
    //    QByteArray root_str = root_Doc.toJson(QJsonDocument::Indented);   //标准JSON格式
    //    qDebug() << root_str; //中文输出乱码
        QString strJson(root_str);
        qDebug() << strJson;
    }

输出结果

{
        "status": "ok",
        "weather": [{
            "date": "2019-07-21",
            "cond_txt": "多云",
            "cond_code": "101",
            "hum": "23",
            "tmp_H": "31",
            "tmp_L": "25"
        }, {
            "date": "2019-07-22",
            "cond_txt": "晴",
            "cond_code": "100",
            "hum": "20",
            "tmp_H": "33",
            "tmp_L": "26"
        }, {
            "date": "2019-07-23",
            "cond_txt": "阵雨",
            "cond_code": "107",
            "hum": "45",
            "tmp_H": "32",
            "tmp_L": "25"
        }],
        "update": "2019-07-21 11:00",
        "Blog": "www.wangchaochao.top"
    }

### 5.构建数组嵌套的JSON字符串 ###

void Create_Array_Nest_JSON(void)
    {
        QJsonArray table_Arr = {"地区", "92号汽油", "95号汽油", "98号汽油", "0号柴油"};
        QJsonArray bj_Arr = {"北京", "6.78", "7.21", "8.19", "6.45"};
        QJsonArray sh_Arr = {"上海", "6.74", "7.17", "7.87", "6.39"};
        QJsonArray js_Arr = {"江苏", "6.75", "7.18", "8.06", "6.37"};
        QJsonArray tj_Arr = {"天津", "6.77", "7.15", "8.07", "6.41"};
    
        QJsonArray data_Arr;    //数组内嵌套了5个数组
        data_Arr.insert(0, table_Arr);
        data_Arr.insert(1, bj_Arr);
        data_Arr.insert(2, sh_Arr);
        data_Arr.insert(3, js_Arr);
        data_Arr.insert(4, tj_Arr);
    
        QJsonObject root_Obj;
    
        root_Obj.insert("status", "ok");
        root_Obj.insert("msg", "全国各省份汽柴油价格信息");
        root_Obj.insert("update", "2019-07-21");
        root_Obj.insert("About", "wcc");
        root_Obj.insert("Blog", "www.wangchaochao.top");
        root_Obj.insert("data", data_Arr);  //数组作为键的值
    
        //创建Json文档
        QJsonDocument root_Doc;
        root_Doc.setObject(root_Obj);
        QByteArray root_str = root_Doc.toJson(QJsonDocument::Compact);  //紧凑格式
    //    QByteArray root_str = root_Doc.toJson(QJsonDocument::Indented);   //标准JSON格式
    //    qDebug() << root_str; //中文输出乱码
        QString strJson(root_str);
        qDebug() << strJson;
    }

输出结果

{
        "status": "ok",
        "msg": "全国各省份汽柴油价格信息",
        "update": "2019-07-21",
        "data": [
            ["地区", "92号汽油", "95号汽油", "98号汽油", "0号柴油"],
            ["北京", "6.78", "7.21", "8.19", "6.45"],
            ["上海", "6.74", "7.17", "7.87", "6.39"],
            ["江苏", "6.75", "7.18", "8.06", "6.37"],
            ["天津", "6.77", "7.15", "8.07", "6.41"]
        ],
        "About": "wcc",
        "Blog": "www.wangchaochao.top"
    }

### 参考资料 ###

*  JSON官方网站：[json][]

[Qt_QJson_JSON_ -]: https://zhuanlan.zhihu.com/p/74901103
[JSON]: https://link.zhihu.com/?target=http%3A//www.wangchaochao.top/2018/11/18/cJSON/
[json]: https://link.zhihu.com/?target=http%3A//www.json.org/json-zh.html