5. HTTP和JSON字符串操作

大部分应用在网络请求中

1.QJsonObject和QByteArray的互相转换

可以将QJsonObject与QByteArray互相转化，以便网络编程时客户端与服务器之间的通信

1.1 QJsonObject转为QByteArray

QJsonObject json;
QByteArray ary;
QJsonDocument doc(json);
ary= doc.toJson();

1.2 QByteArray转为QJsonObject

QByteArray ary;
QJsonObject json;
json = QJsonDocument::fromJson(ary).object();

2.HTTP操作

下列代码使用网上别人写好的一个库

2.1 get

m_httpClient 是成员变量
void Httptest::httpTest()
{
    m_httpClient.get("http://122.51.80.50:8000/pump/")
                .queryParam("pump_code", "001")
                .onResponse([](QByteArray result){
                    QJsonObject json;
                    json = QJsonDocument::fromJson(result).object();
        //          QJsonArray array = json.value("results").toArray();
        //          qDebug() << "Result: " << array[1].toObject()["pump_code"].toString();
                    qDebug() << "result " << json;
                })
                .onError([](QString errorStr){
                    qDebug()<<"Error: "<<errorStr;
                })
                .exec();
}

获取到的数据

2.2 put

void Httptest::httpPut()
{
    QJsonObject content;
    content.insert("fluid_flow", "20");
    content.insert("mod_by", "3131f40fcb1b41a9a5bca7b41689b85a");
    qDebug() << "content = " << content;
    m_httpClient.put("http://122.51.80.50:8000/pump/1d3506ac8e0348879f9f483441365ad5/")
                .header("content-type", "application/json")
                .body(content)
                .onResponse([](QByteArray result){
                    qDebug() << "成功";
                    //qDebug() << result;
                })
                .onError([](QString errorStr){
                       qDebug()<<"Error: "<<errorStr;
                })
                .exec();
}

代码如下：
webhttp.rar
2。3 POST

bool MyHttp::sendSensorConfig()
{
    //没有网络就结束
    //插入设备编号
    QJsonObject content;
    content.insert("equipment_code", getEquipmentCode());
    content.insert("sensor_string", getSensorName());
    content.insert("high_sensor_threshold_string", getSensorThread(high));
    content.insert("down_sensor_threshold_string", getSensorThread(low));
    content.insert("sensor_code_string", getSensorCode());
    content.insert("equip_person", setting.getSetting("equipment", "configPerson"));
    QString sensorUrl = QString("http://%1:8000/equipment/").arg(getUrl());
    m_httpClient.post(sensorUrl)
            .header("content-type", "application/json")
            .body(content)
            .onResponse([=](QByteArray result){
                Q_UNUSED(result);
//                qDebug() << "传感器配置成功";
                correct = true;
            })
            .onError([=](QString errorStr){
                correct = false;
                qDebug() << errorStr;
            })
            .block()
            .timeout(2000)
            .exec();
    return correct;
}

2. JSON操作

包含头文件

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

获取到的JSON数据

({"count":1,
  "results":[{"create_by":"75bd4fd79e48448ebae23c905973a742",
  "create_time":"2021-01-28",
  "equipment_code":"20210128w",
  "fluid_flow":"35(已修改)",
  "mod_by":"3131f40fcb1b41a9a5bca7b41689b85a",
  "mod_time":"2021-02-04","note":"测试",
  "pump_code":"001",
  "pump_id":"1d3506ac8e0348879f9f483441365ad5",
  "pump_name":"测试泵1号",
  "status":"1"}]
})

一般获得http的数据是QByteArray
先转换为JSON

//result是如上的代码
QJsonObject json;
json = QJsonDocument::fromJson(result).object();
//取值  取result的值  返回值是QJsonValue  
QJsonValue value = json.value("results");
//同上一样
QJsonValue value = json["results"];
//打印为结果1 
qDebug() << "array " << value;

结果1

QJsonValue(array, 
           QJsonArray([{"create_by":"75bd4fd79e48448ebae23c905973a742",
                        "create_time":"2021-01-28",
                        "equipment_code":"20210128w",
                        "fluid_flow":"20","mod_by":"3131f40fcb1b41a9a5bca7b41689b85a",
                        "mod_time":"2021-02-20","note":"测试",
                        "pump_code":"001",
                        "pump_id":"1d3506ac8e0348879f9f483441365ad5",
                        "pump_name":"测试泵1号",
                        "status":"1"}])

注意返回的是一个QJsonArray，我们需要
继续从上述取值
我们需要先转换为QJsonArray然后转换为value或者【】取值

//QJsonArray
QJsonArray value = json["results"].toArray();
// QJsonValue(object, QJsonObject...      QJsonValue(string, "测试泵1号")
QJsonValue value2 = value[0].toObject().value("pump_name");
//转为字符串  "测试泵1号"
QString value3 = value2.toString();

遍历

数组遍历 foreach

QJsonObject json;
json = QJsonDocument::fromJson(result).object();
QJsonArray value = json["data"].toArray();
int i = 0;
foreach (QJsonValue test, value) {
    qDebug() << "test = " << test;
    qDebug() << "i = " << i++;
}

for循环

QJsonObject json;
json = QJsonDocument::fromJson(result).object();
QJsonArray value = json["data"].toArray();
QJsonArray::iterator iteratorArray = value.begin();
for (int i = 0; i < value.size(); i++) {
    qDebug() << iteratorArray[i];
    qDebug() << "i = " << i;
}