本章是入门章节,讲解如何实现一个附带界面的服务器,后续会完善与优化
- 使用qt编译libevent
 - 源码
 - 演示视频
 - qt的一些知识
 
 
1.主要功能有登录界面
2.基于libevent实现的服务器的业务功能
使用qt编译libevent
下载这个,其他版本也可以
 主要是github上下载,可能有点卡
 链接: link
 
 
 编译流程
 1.打开qt然后点下面的红框
 
 2.选cmakelist
 
 3.选编译器
 4.最后一步编译
 
 5.编译成功后库的位置
 
 
 最后编译成功后可以丢到/usr/bin里也可以丢到自己的写的程序的目录下
源码
源码结构如下
 
 下面是libeventuse.cpp
#include "libeventuse.h"
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include <signal.h>
#ifndef _WIN32
#include <netinet/in.h>
# ifdef _XOPEN_SOURCE_EXTENDED
#  include <arpa/inet.h>
# endif
#include <sys/socket.h>
#endif
#include <event2/bufferevent.h>
#include <event2/buffer.h>
#include <event2/listener.h>
#include <event2/util.h>
#include <event2/event.h>
#include"qdebug.h"
static const char MESSAGE[] = "Hello, World!\n";
static const unsigned short PORT = 9995;
static void listener_cb(struct evconnlistener *, evutil_socket_t,
    struct sockaddr *, int socklen, void *);
static void conn_writecb(struct bufferevent *, void *);
static void conn_eventcb(struct bufferevent *, short, void *);
static void signal_cb(evutil_socket_t, short, void *);
int main3()
{
    struct event_base *base;
    struct evconnlistener *listener;
    struct event *signal_event;
    struct sockaddr_in sin = {0};
    base = event_base_new();//初始化
    if (!base) {
        fprintf(stderr, "Could not initialize libevent!\n");
        return 1;
    }
    sin.sin_family = AF_INET;
    sin.sin_port = htons(PORT);
    listener = evconnlistener_new_bind(base, listener_cb, (void *)base,
        LEV_OPT_REUSEABLE|LEV_OPT_CLOSE_ON_FREE, -1,
        (struct sockaddr*)&sin,
        sizeof(sin));//事件监听
    if (!listener) {
        fprintf(stderr, "Could not create a listener!\n");
        return 1;
    }
    signal_event = evsignal_new(base, SIGINT, signal_cb, (void *)base);//信号事件
    if (!signal_event || event_add(signal_event, NULL)<0) {
        fprintf(stderr, "Could not create/add a signal event!\n");
        return 1;
    }
    event_base_dispatch(base);//启动
    evconnlistener_free(listener);
    event_free(signal_event);
    event_base_free(base);
    printf("done\n");
    return 0;
}
static void
listener_cb(struct evconnlistener *listener, evutil_socket_t fd,
    struct sockaddr *sa, int socklen, void *user_data)
{
    struct event_base *base = static_cast<event_base*>(user_data);
    struct bufferevent *bev;
    bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE);
    if (!bev) {
        fprintf(stderr, "Error constructing bufferevent!");
        event_base_loopbreak(base);
        return;
    }
    bufferevent_setcb(bev, NULL, conn_writecb, conn_eventcb, NULL);
    bufferevent_enable(bev, EV_WRITE);
    bufferevent_disable(bev, EV_READ);
    bufferevent_write(bev, MESSAGE, strlen(MESSAGE));
}
static void
conn_writecb(struct bufferevent *bev, void *user_data)
{
    struct evbuffer *output = bufferevent_get_output(bev);
    if (evbuffer_get_length(output) == 0) {
        printf("flushed answer\n");
        bufferevent_free(bev);
    }
}
static void
conn_eventcb(struct bufferevent *bev, short events, void *user_data)
{
    if (events & BEV_EVENT_EOF) {
        printf("Connection closed.\n");
    } else if (events & BEV_EVENT_ERROR) {
        printf("Got an error on the connection: %s\n",
            strerror(errno));/*XXX win32*/
    }
    /* None of the other events can happen here, since we haven't enabled
     * timeouts */
    bufferevent_free(bev);
}
static void
signal_cb(evutil_socket_t sig, short events, void *user_data)
{
    struct event_base *base = static_cast<event_base*>(user_data);
    struct timeval delay = { 2, 0 };
    printf("Caught an interrupt signal; exiting cleanly in two seconds.\n");
    event_base_loopexit(base, &delay);
}
libeventuse::libeventuse()
{
    main3();
}
 
下面是mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "ui_form.h"
#include"QString"
#include"qdebug.h"
#include"qmessagebox.h"
#include"libeventuse.h"
#include <QMutex>
#include <QTime>
#include <QWidget>
WorkThread::WorkThread(QObject *parent) : QThread(parent) {}
void WorkThread::run() {  // 必须实现 run()
libeventuse tmp;
emit this->server_finish();
}
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
   login_win=new Form;
   workthread=new WorkThread;
   login_win->hide();//登录窗口打开
   workthread->start();
   connect(this->workthread,&WorkThread::server_finish,[=](){
            qDebug()<<"服务器关闭";
   });
   connect(this->workthread,&WorkThread::finished,this->workthread,&QObject::deleteLater);
   connect(this->login_win,&Form::back,[=](){//槽函数
       this->show();//返回登录界面
       this->login_win->hide();//主执行界面关闭
   });
}
MainWindow::~MainWindow()
{
    delete login_win;
    delete ui;
}
Form::Form(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Form)
{
    ui->setupUi(this);
}
Form::~Form()
{
    delete ui;
}
void MainWindow::on_pushButton_clicked()
{
    QString RootName=ui->rootName->text();
    QString Password=ui->password->text();
    if(RootName.size()==0)
    {
       QMessageBox::information(this, tr("提示"), tr("用户名没有输入"));
       return ;
    }
    else if(RootName.size()==0)
    {
        QMessageBox::information(this, tr("提示"), tr("密码没有输入"));
    }
    if(RootName=="i"&&Password=="1")//验证用户和密码
    {
        qDebug()<<RootName<<Password;
        login_win->show();//主执行界面打开
        this->hide();//登录界面关闭
    }
    else
    {
          QMessageBox::information(this, tr("提示"), tr("用户或密码输入错误"));
    }
}
void Form::on_pushButton_clicked()
{
    emit this->back();//发送信号
}
void MainWindow::on_pushButton_2_clicked()
{
}
 
下面是libeventuse.h
#ifndef LIBEVENTUSE_H
#define LIBEVENTUSE_H
class libeventuse
{
public:
    libeventuse();
};
#endif // LIBEVENTUSE_H
 
下面是mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
namespace Ui {
class Form;
}
class Form : public QWidget
{
    Q_OBJECT
public:
    explicit Form(QWidget *parent = 0);
    ~Form();
private slots:
    void on_pushButton_clicked();
signals:
    void back();
private:
    Ui::Form *ui;
};
#include <QThread>
class WorkThread : public QThread {
    Q_OBJECT  // 必须添加!!!
public:
    explicit WorkThread(QObject *parent = nullptr);
protected:
    void run() override;  // 虚函数声明
signals:
void WorkThread_signal(int b);//自定义的信号
void server_finish();
};
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
    Q_OBJECT
public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
   Form* login_win=nullptr;
   WorkThread*workthread=nullptr;
private slots:
   void on_pushButton_clicked();
   void on_pushButton_2_clicked();
private:
    Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H
 
pro文件的配置
 
演示视频
20250415_153450
我视频第一部分展示了如何在qt创建窗口
 视频第二部分展示了客户端连接到服务器后会接收到hello world
 视频等审核过了我再放上来
 审核没过我就发效果图
 
qt的一些知识

 1.信号的格式
 signals:
 void WorkThread_signal(int b);//自定义的信号
 2.注意事项,需要分写入Q_OBJECT才能这么定义
 3.信号发送使用 emit 发送
 
 4.使用connect槽函数来绑定信号要处理的逻辑
 



















