Qt实现HTTP表单提交

图片源自Qt官网

Qt是一款跨平台的C++图形用户界面应用程序开发框架。就是可以拿它来开发桌面端程序。接触Qt已经是六年前的事情了，当初还是Qt 4.x，现在已经更新到Qt 5.x了。今天来分享下Qt下实现HTTP的表单提交，后台用Java提供一个简单的HTTP接口，完成整个前后台的交互。

1. 新建项目

首先新建一个Qt Widgets Application的窗体程序，这里仅做简单演示，因此基类选择QDialog。

image image

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今天的主题是HTTP post提交表单，因此要用到Qt的network模块，在.pro文件中加入该模块：

2. 项目配置

QT += core gui network

3. 在designer界面设计器中进行界面设计

image

4. 编写dialog.h头文件代码

#ifndef DIALOG_H
#define DIALOG_H

#include <QDialog>
#include <QtNetwork/QNetworkAccessManager>

namespace Ui {
class Dialog;
}

class Dialog : public QDialog
{
    Q_OBJECT

public:
    explicit Dialog(QWidget *parent = nullptr);
    ~Dialog();

private slots:
    // http响应槽函数
    void ReplaySlot(QNetworkReply *reply);
    // 表单提交响应槽函数
    void on_submitBtn_clicked();

private:
    Ui::Dialog *ui;
    QNetworkAccessManager *netAccessManager;

};

#endif // CREATE_CLASSROOM_DIALOG_H

5. 编写dialog.cpp源文件代码

#include "dialog.h"
#include "ui_dialog.h"
#include <QNetworkReply>

Dialog::Dialog(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::Dialog)
{
    ui->setupUi(this);
    netAccessManager = new QNetworkAccessManager(this);

    connect(netAccessManager, SIGNAL(finished(QNetworkReply *)), this, SLOT(ReplaySlot(QNetworkReply *)));
}

void Dialog::ReplaySlot(QNetworkReply *reply) {
    int statusCode = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
    qDebug() << "statusCode:" << statusCode;
}

Dialog::~Dialog()
{
    delete ui;
    if(netAccessManager != Q_NULLPTR) {
        delete netAccessManager;
    }
}


void Dialog::on_submitBtn_clicked()
{
    QString name = ui->nameLineEdit->text();
    qint64 startTime = ui->startDateTimeEdit->dateTime().toMSecsSinceEpoch();
    qint64 endTime = ui->endDateTimeEdit->dateTime().toMSecsSinceEpoch();
    int count = ui->cntSpinBox->value();

    QString formInfo = QString("name=%1&startTime=%2&endTime=%3&count=%4")
            .arg(name).arg(startTime).arg(endTime).arg(count);
    QByteArray content = formInfo.toUtf8();
    int contentLength = content.length();

    QNetworkRequest netReq;
    netReq.setUrl(QUrl("http://127.0.0.1:8080/apply"));
    netReq.setHeader(QNetworkRequest::ContentTypeHeader, "application/x-www-form-urlencoded");
    netReq.setHeader(QNetworkRequest::ContentLengthHeader, contentLength);

    netAccessManager->post(netReq, content);
}

6. 编写Java后台接口代码

@Slf4j
@Controller
@RequestMapping("")
public class ClassManagerController {

    @PostMapping("apply")
    @ResponseBody
    public String createClassRoom(Map<String, Object> info) {
        //TODO 其他业务操作
        return "success";
    }
}

至此，所有代码编写完成，首先把Java程序运行，然后把Qt程序运行，填写好表单，点击确定，即可完成一次HTTP请求。

左手C++，右手Java，无不欢喜，哈哈~~