二、使用 QJson 解析 json 数据

如何获取并编译 QJson，参见我前面文章 一、编译QJson（避免采坑教程）​，下面只讲使用，案例如下：
Person

#person.h

#ifndef PERSON_H
#define PERSON_H

#include <QObject>
#include <QDate>

class Person : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QString name READ name WRITE setName)
    Q_PROPERTY(int phoneNumber READ phoneNumber WRITE setPhoneNumber)
    Q_PROPERTY(Gender gender READ gender WRITE setGender)
    Q_PROPERTY(QDate brithday READ brithday WRITE setBrithday)
    Q_ENUMS(Gender)

public:
    explicit Person(QObject *parent = nullptr);
    ~Person();

    QString name() const;
    void setName(const QString& name);

    /**
     * const：该函数为只读函数，不容许修改成员变量的值
     */
    int phoneNumber() const;
    void setPhoneNumber(const int phoneNumber);

    enum Gender {Male, Female};
    void setGender(Gender gender);
    Gender gender() const;

    QDate brithday() const;
    void setBrithday(const QDate& dob);
private:
    QString m_name;
    int m_phoneNumber;
    Gender m_gender;
    QDate m_dob;
};

#endif // PERSON_H

-----------------------------------------------

#person.cpp

#include "person.h"

Person::Person(QObject *parent) : QObject(parent)
{

}

Person::~Person()
{

}

QString Person::name() const
{
    return m_name;
}

void Person::setName(const QString &name)
{
    m_name = name;
}

int Person::phoneNumber() const
{
    return m_phoneNumber;
}

void Person::setPhoneNumber(const int phoneNumber)
{
    m_phoneNumber = phoneNumber;
}

void Person::setGender(Person::Gender gender)
{
    m_gender = gender;
}

Person::Gender Person::gender() const
{
    return m_gender;
}

QDate Person::brithday() const
{
    return m_dob;
}

void Person::setBrithday(const QDate &dob)
{
    m_dob = dob;
}

使用

/**
 * @brief Json 转成 QVariant对象
 */
void Widget::testJsonToVariant()
{
    QJson::Parser parser;
    bool ok;
    QString json("{"
            "\"encoding\" : \"UTF-8\","
            "\"plug-ins\" : ["
            "\"python\","
            "\"c++\","
            "\"ruby\""
            "],"
            "\"indent\" : { \"length\" : 3, \"use_space\" : true }"
            "}");
    QVariantMap result = parser.parse(json.toUtf8(), &ok).toMap();
    if (!ok) {
        qFatal("An error occurred during parsing");
        exit (1);
    }
    qDebug() << "encoding:" << result["encoding"].toString();
    qDebug() << "plugins:";
    foreach (QVariant plugin, result["plug-ins"].toList()) {
        qDebug() << "\t-" << plugin.toString();
    }
    QVariantMap nestedMap = result["indent"].toMap();
    qDebug() << "length:" << nestedMap["length"].toInt();
    qDebug() << "use_space:" << nestedMap["use_space"].toBool();
}
/**
 * @brief QVariant 转成 Json 对象
 */
void Widget::testVariantToJson()
{
    QVariantList peoples;

    QVariantMap bob;
    bob.insert("name", "bob");
    bob.insert("age", "21");

    QVariantMap alice;
    alice.insert("name", "alice");
    alice.insert("age", "23");

    peoples << bob << alice;

    QJson::Serializer serializer;
    bool ok = false;
    QByteArray jsonArr = serializer.serialize(peoples, &ok);
    if (ok)
        qDebug() << jsonArr;
    else
        qCritical() << "Something went wrong:" << serializer.errorMessage();
}

/**
 * @brief QObject 转成 Json
 */
void Widget::testPerson2Json()
{
    Person person;
    person.setName("bob");
    person.setGender(Person::Male);
    person.setPhoneNumber(14751087620);
    person.setBrithday(QDate(1993, 6, 10));

    QVariantMap variant = QJson::QObjectHelper::qobject2qvariant(&person);
    QJson::Serializer serializer;
    qDebug() << serializer.serialize(variant);
}
/**
 * @brief Json 转成 QObject
 */
void Widget::testJson2Person()
{
    bool ok = false;
    QString json = "{ \"brithday\" : \"1993-06-10\", \"gender\" : 0, \"name\" : \"bob\", \"phoneNumber\" : 1866185732 }";
    QJson::Parser parser;
    QVariant variant = parser.parse(json.toUtf8(), &ok);
    Person person;
    QJson::QObjectHelper::qvariant2qobject(variant.toMap(), &person);
    qDebug() << person.name();
}