qt使用http get和post

准备

使用到网络编程，需要在Pro文件中加入如下语句

QT       += network

get请求

widge.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QtNetwork/QNetworkRequest>
#include <QtNetwork/QNetworkReply>
#include <QtNetwork/QNetworkAccessManager>

QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE

class Widget : public QWidget
{
    Q_OBJECT

public:
    Widget(QWidget *parent = nullptr);
    ~Widget();

    void get(QString str);
    void getBack(QNetworkReply* reply);

private slots:
    void on_pushButton_2_clicked();

private:
    Ui::Widget *ui;
    QNetworkAccessManager * manager;
};
#endif // WIDGET_H

widget.cpp

#include "widget.h"
#include "ui_widget.h"
#include <QDebug>
#include <QJsonObject>
#include <QJsonDocument>

Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
}

Widget::~Widget()
{
    delete ui;
}

void Widget::on_pushButton_2_clicked()
{
    QString str = ui->lineEdit_2->text();

    manager = new QNetworkAccessManager(this);
    connect(manager,&QNetworkAccessManager::finished,this,&Widget::getBack);//通信完成后，自动执行getBack
    get(str);
}


void Widget::get(QString str)
{
    // 构造请求
    QNetworkRequest request;
    request.setUrl(QUrl(str));
    request.setHeader(QNetworkRequest::ContentTypeHeader, "application/json");
    // 发送请求
    manager->get(request);

}


void Widget::getBack(QNetworkReply* reply)
{
    ui->textEdit_2->setText(reply->readAll().data());
}

post请求

widge.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QtNetwork/QNetworkRequest>
#include <QtNetwork/QNetworkReply>
#include <QtNetwork/QNetworkAccessManager>

QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE

class Widget : public QWidget
{
    Q_OBJECT

public:
    Widget(QWidget *parent = nullptr);
    ~Widget();

    void post(QString str);
    void postBack(QNetworkReply* reply);

private slots:
    void on_pushButton_clicked();

private:
    Ui::Widget *ui;
    QNetworkAccessManager * manager;
};
#endif // WIDGET_H

widget.cpp

#include "widget.h"
#include "ui_widget.h"
#include <QDebug>
#include <QJsonObject>
#include <QJsonDocument>

Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
}

Widget::~Widget()
{
    delete ui;
}


void Widget::on_pushButton_clicked()
{
    QString str = ui->lineEdit->text();

    manager = new QNetworkAccessManager(this);
    connect(manager,&QNetworkAccessManager::finished,this,&Widget::postBack);//通信完成后，自动执行getBack
    post(str);

}

//具体实现代码参考下面的分类情况
void Widget::post(QString str)
{
    QByteArray dataArray;
    ...
    request.setUrl(QUrl(str));
    // 发送请求
    manager->post(request, dataArray);

}


void Widget::postBack(QNetworkReply* reply)
{
    ui->textEdit->setText(reply->readAll().data());
}

post请求的数据格式

参数写在url后面

跟get一样，dataArray为空即可

http://127.0.0.1:18080/define/login?userId=1&password=123

void Widget::post(QString str)
{
    // 表单数据
    QByteArray dataArray;
    // 构造请求
    request.setUrl(QUrl(str));
    //可以不写，都能识别，默认为x-www-form-urlencoded
    request.setHeader(QNetworkRequest::ContentTypeHeader, "application/x-www-form-urlencoded");
    // 发送请求
    manager->post(request, dataArray);
}

content-type missing in HTTP POST, defaulting to application/x-www-form-urlencoded. Use QNetworkRequest::setHeader() to fix this problem.

对应的后端接口

public ResponseEntity<Map> login(Integer userId, String password)

public ResponseEntity<Map> login(@RequestParam Map<String, String> params)

使用application/x-www-form-urlencoded

form表单数据被编码为key1=value1&key2=value2格式发送到服务器

http://127.0.0.1:18080/define/login

使用QByteArray

void Widget::post(QString str)
{
    // 表单数据
    QByteArray dataArray;
    dataArray.append("userId=1&");
    dataArray.append("password=123");
    // 构造请求
    request.setUrl(QUrl(str));
    request.setHeader(QNetworkRequest::ContentTypeHeader, "application/x-www-form-urlencoded");
    // 发送请求
    manager->post(request, dataArray);
}

或使用QString转utf8

void Widget::post(QString str)
{
    // 表单数据
    QString ss = "userId=1&password=123";
    // 构造请求
    request.setUrl(QUrl(str));
    request.setHeader(QNetworkRequest::ContentTypeHeader, "application/x-www-form-urlencoded");
    // 发送请求
    manager->post(request, ss.toUtf8());
}

postman访问接口

对应的后端接口

public ResponseEntity<Map> login(Integer userId, String password)

public ResponseEntity<Map> login(@RequestParam Map<String, String> params)

使用application/json

内容数据为Json对象

http://127.0.0.1:18080/define/login

void Widget::post(QString str)
{
    // Json数据
    QJsonObject json;
    json.insert("userId", "1");
    json.insert("password", "123");

    QJsonDocument document;
    document.setObject(json);
    QByteArray dataArray = document.toJson(QJsonDocument::Compact);

    request.setUrl(QUrl(str));

    request.setHeader(QNetworkRequest::ContentTypeHeader,QVariant("application/json;charset=utf-8"));

    // 发送请求
    manager->post(request, dataArray);

}

postman访问接口

对应的后端接口

public ResponseEntity<Map> login(@RequestBody User user)

public ResponseEntity<Map> login(@RequestBody Map<String, String> params)

使用multipart/form-data传送文件

http://127.0.0.1:18080/define/upload

#include <QJsonObject>
#include <QFile>
#include <QJsonDocument>
#include <QHttpMultiPart>

void Widget::post(QString str)
{
    QString filePath = "/Users/xx/qthttp.jpg";
    QFile* file = new QFile(filePath);
    file->open(QIODevice::ReadOnly);

    QHttpMultiPart* multiPart = new QHttpMultiPart(QHttpMultiPart::FormDataType);

    QHttpPart imagePart;
    imagePart.setHeader(QNetworkRequest::ContentDispositionHeader,
                      QVariant(QString("form-data; name=\"file\";filename=\"qthttp.jpg\";")));
    imagePart.setBodyDevice(file);
    multiPart->append(imagePart);

    // 构造请求
    QNetworkRequest request;
    request.setUrl(QUrl(str));

    // 发送请求
    manager->post(request, multiPart);
}

对应的后端接口

public ResponseEntity<Map> upload(@RequestParam("file") MultipartFile multipartFile)