服务器端

#include "widget.h"
#include "ui_widget.h"Widget::Widget(QWidget *parent): QWidget(parent), ui(new Ui::Widget)
{ui->setupUi(this);//准备组件，初始化组件状态this->setFixedSize(800,600);chatwidget = new QListWidget(this);chatwidget->setFixedSize(800,430);chatwidget->setEnabled(false);portedit = new QLineEdit(this);portedit->resize(400,50);portedit->move(80,480);startbtn = new QPushButton("启动",this);startbtn->setStyleSheet("background-color:red");startbtn->resize(150,80);startbtn->move(520,465);//startbtn按钮的点击信号与槽函数连接connect(startbtn,&QPushButton::clicked,this,&Widget::startbtn_slot);ser = new QTcpServer(this);//实意化服务器类对象connect(ser,&QTcpServer::newConnection,this,&Widget::serconnect_slot); //连接 每当新的客户端连接，服务器发出的newconection信号 与对应的槽函数}
Widget::~Widget()
{delete ui;
}//startbtn按钮的点击信号对应的槽函数
void Widget::startbtn_slot()
{if(startbtn->text() == "启动"){//启动按钮后调用监听int port = portedit->text().toUInt();//获取行编辑器输入的端口号if(port<1024 || port>49151){QMessageBox::information(this,"提示","端口号不可用");return;}if(ser->listen(QHostAddress::Any,port)==true)//设置服务器的IP地址端口号,监听状态{//启用聊天窗口，禁用端口行编辑器,设置按钮背景色chatwidget->setEnabled(true);portedit->setEnabled(false);startbtn->setStyleSheet("background-color:blue");QMessageBox::information(this,"成功","服务器启动成功");startbtn->setText("关闭");//启动后将按钮文本设置为关闭}else{QMessageBox::information(this,"失败","服务器启动失败");}}else if(startbtn->text() == "关闭"){chatwidget->setEnabled(false);portedit->setEnabled(true);startbtn->setStyleSheet("background-color:red");QMessageBox::information(this,"成功","服务器关闭");startbtn->setText("开启");//启动后将按钮文本设置为开启}
}//服务器发出的newconection信号对应的槽函数处理
void Widget::serconnect_slot()
{QTcpSocket *socket = ser->nextPendingConnection();//返回连接到的客户端信息clilist.append(socket);//将信息放到容器中保存//每当有客户端向服务器发送数据时，socket会向服务器发送一个readyread信号connect(socket,&QTcpSocket::readyRead,this,&Widget::socket_readyread);//将所连接客户端的服务器都连接到槽函数
}//处理socket发送的readyread信号的槽函数
void Widget::socket_readyread()
{//在这个函数内就可以实现数据收发//先遍历链表中的客户端，如果是无效链接则删除掉for(int i=0;i<clilist.length();i++){//判断连接状态if(clilist[i]->state() == QTcpSocket::UnconnectedState) //判断这个链接状态是否是无效链接{//是则删除clilist.removeAt(i);}//不是无效链接判断是否有数据待读else if(clilist[i]->bytesAvailable() != 0){QByteArray msg = clilist[i]->readAll();//将客户端发来的数据督导msg里面chatwidget->addItem(QString::fromLocal8Bit(msg));//将信息展示在聊天框上//遍历转发除了发送信息客户端for(int j=0;j<clilist.length();j++){if(i!=j){clilist[j]->write(msg);}}}}
}

客户端 

#include "widget.h"
#include "ui_widget.h"Widget::Widget(QWidget *parent): QWidget(parent), ui(new Ui::Widget)
{ui->setupUi(this);this->setFixedSize(800,600);chatwidget = new QListWidget(this);chatwidget->resize(800,400);chatwidget->setEnabled(false);usrlab = new QLabel("用户名",this);usrlab->move(30,470);usredit = new QLineEdit(this);usredit->move(90,460);usredit->resize(300,30);iplab = new QLabel("ip",this);iplab->move(30,510);ipedit = new QLineEdit(this);ipedit->move(90,500);ipedit->resize(300,30);portlab = new QLabel("port",this);portlab->move(30,545);portedit = new QLineEdit(this);portedit->move(90,540);portedit->resize(300,30);msgedit = new QLineEdit(this);msgedit->move(90,410);msgedit->resize(400,40);msgedit->setEnabled(false);sendbtn = new QPushButton("发送",this);sendbtn->move(510,408);sendbtn->resize(150,47);
//    sendbtn->setStyleSheet("background-color:red");sendbtn->setEnabled(false);connectbtn = new QPushButton("连接服务器",this);connectbtn->move(480,490);connectbtn->resize(200,80);connectbtn->setStyleSheet("background-color:red");cli = new QTcpSocket(this);//实意化客户端类对象//点击连接服务器按钮的信号与槽函数连接connect(connectbtn,&QPushButton::clicked,&Widget::connectbtn_slot);connect(sendbtn,&QPushButton::clicked,&Widget::sendbtn_slot);//客户端连接信号与槽函数连接connect(cli,&QTcpSocket::connected,this,&Widget::connected_slot);connect(msgedit,&QLineEdit::textChanged,this,&Widget::sentbtn_available_slot);}void Widget::connected_slot()
{QMessageBox::information(this,"连接","连接服务器成功！！");
}void Widget::connectbtn_slot()
{//一按钮两用if(connectbtn->text()=="连接服务器"){//点击连接服务器之后获取行编辑器的文本信息QString usrname=usredit->text();quint16 port=portedit->text().toUInt();QString ip=ipedit->text();//连接整个后禁用服务器端信息编辑，启用聊天窗口和信息编辑器chatwidget->setEnabled(true);msgedit->setEnabled(true);usredit->setEnabled(false);ipedit->setEnabled(false);portedit->setEnabled(false);//向给定的IP地址端口号发送链接请求cli->connectToHost(ip,port);connectbtn->setText("断开服务器");//连接成功后会发送cli会发送一个connected信号，对这个信号处理即可}else{//断开连接整个后启用服务器端信息编辑，禁用聊天窗口和信息编辑器usredit->setEnabled(true);ipedit->setEnabled(true);portedit->setEnabled(true);chatwidget->setEnabled(false);sendbtn->setEnabled(false);msgedit->setEnabled(false);QString msg = usrname + "离开聊天室" ;cli->write(msg.toLocal8Bit());cli->disconnectFromHost();connectbtn->setText("连接服务器");}
}void Widget::sendbtn_slot()
{QString msg= usrname + ":" + msgedit->text();cli->write(msg.toLocal8Bit());QString msg1=msgedit->text();QListWidgetItem *Item=new QListWidgetItem(msg1);Item->setTextAlignment(Qt::AlignRight);   //自己发送的文本右边显示chatwidget->addItem(Item);msgedit->clear();
}//处理readyread对应槽函数
void Widget::readyRead_slot()
{QByteArray msg =cli->readAll();chatwidget->addItem(QString::fromLocal8Bit(msg));}void Widget::disconnect_slot()
{QMessageBox::information(this,"断开","断开服务器连接成功");
}void Widget::sentbtn_available_slot()
{if(msgedit->text().length()>0){sendbtn->setEnabled(true);}
}Widget::~Widget()
{delete ui;
}

 学生管理系统

#include "widget.h"
#include "ui_widget.h"Widget::Widget(QWidget *parent): QWidget(parent), ui(new Ui::Widget)
{ui->setupUi(this);if(!db.contains("mydb.db")){db = QSqlDatabase::addDatabase("QSQLITE");db.setDatabaseName("mydb.db");}if(!db.open()){QMessageBox::information(this,"失败","数据库打开失败");return;}QString sql = "create table if not exists Stu(numb int ,name char,sex char,score float);";QSqlQuery query;if(query.exec(sql)==false){QMessageBox::information(this,"提示","创建数据表失败");return;}}Widget::~Widget()
{delete ui;
}void Widget::on_addbtn_clicked()
{ui->tableWidget->clear();//QString sql = QString(%1)int ui_numb=ui->numbedit->text().toUInt();QString ui_name= ui->nameedit->text();QString ui_sex = ui->sexedit->text();float ui_score = ui->scoreedit->text().toFloat();if(ui_sex==NULL || ui_numb==0 || ui_score==0 || ui_name==NULL){QMessageBox::information(this,"提示","请将信息填写完整");return;}else if(!(ui_sex == "男" || ui_sex == "女")){QMessageBox::information(this,"提示","性别信息错误");return;}QString sql = QString("insert into Stu values(%1,'%2','%3',%4);").arg(ui_numb).arg(ui_name).arg(ui_sex).arg(ui_score);QSqlQuery query;if(query.exec(sql)){QMessageBox::information(this,"提示","添加数据成功");ui->numbedit->clear();ui->nameedit->clear();ui->sexedit->clear();ui->scoreedit->clear();return;}else{QMessageBox::information(this,"提示","添加数据失败");return;}
}void Widget::on_searchbtn_clicked()
{ui->tableWidget->clear();QString sql;if(ui->numbedit->text()==NULL){sql = "select * from Stu";}else{sql = QString("select * from stu where numb=%1;").arg(ui->numbedit->text());}QSqlQuery query;if(!query.exec(sql)){QMessageBox::information(this,"提示","查询失败");return;}int i=0;while(query.next()){//任意一个查询的结果//qDebug() << query.record().value(1).toString();for(int j=0;j<query.record().count();j++){qDebug() << query.record().value(j).toString();QTableWidgetItem *Item=new QTableWidgetItem(query.record().value(j).toString());Item->setTextAlignment(Qt::AlignCenter);ui->tableWidget->setItem(i,j,Item);}i++;}
}void Widget::on_updatabtn_clicked()
{ui->tableWidget->clear();int ui_numb=ui->numbedit->text().toUInt();QString ui_name= ui->nameedit->text();QString ui_sex = ui->sexedit->text();float ui_score = ui->scoreedit->text().toFloat();if(ui_sex==NULL || ui_numb==0 || ui_score==0 || ui_name==NULL){QMessageBox::information(this,"提示","请将信息填写完整");return;}else if(!(ui_sex == "男" || ui_sex == "女")){QMessageBox::information(this,"提示","性别信息错误");return;}//QString sql = QString("update Stu set numb=%1 where name='%2'").arg(ui_numb).arg(ui_name);//qDebug() << sql;QString sql = QString("update Stu set name='%1',sex='%2',score=%3 where numb=%4;").arg(ui_name).arg(ui_sex).arg(ui_score).arg(ui_numb);QSqlQuery query;if(query.exec(sql))//{QMessageBox::information(this,"提示","修改数据成功");ui->numbedit->clear();ui->nameedit->clear();ui->sexedit->clear();ui->scoreedit->clear();return;}else{QMessageBox::information(this,"提示","修该数据失败");query.lastError();return;}
}
//lasrErrorvoid Widget::on_delbtn_clicked()
{ui->tableWidget->clear();int ui_numb=ui->numbedit->text().toUInt();if( ui_numb==0 ){QMessageBox::information(this,"提示","请填写正确学号");return;}QString sql = QString("delete from Stu where numb=%1;").arg(ui_numb);QSqlQuery query;if(query.exec(sql))//{QMessageBox::information(this,"提示","删除数据成功");ui->numbedit->clear();ui->nameedit->clear();ui->sexedit->clear();ui->scoreedit->clear();return;}else{QMessageBox::information(this,"提示","删除数据失败");query.lastError();return;}
}void Widget::on_sortbtn_clicked()
{//  int ui_numb=ui->numbedit->text().toUInt();
//     QMessageBox box(QMessageBox::Question,"选择","请选择学号或者分数排序",QMessageBox::Ok|QMessageBox::Save);
//     box.setDefaultButton(QMessageBox::Ok);
//     box.setButtonText(QMessageBox::Ok,"学号");
//     box.setButtonText(QMessageBox::Save,"分数");
//     int res = box.exec();
//     QString sql;
//     if(res==QMessageBox::Ok)
//     {
//        sql = QString("select * from Stu order by numb asc");
//     }
//     else if(res==QMessageBox::Save)
//     {
//         sql = QString("select * from Stu order by score asc");
//     }QString sql="select * from Stu ORDER BY score;";QSqlQuery query;ui->tableWidget->clear();if(query.exec(sql))//{QMessageBox::information(this,"提示","更改排序成功");ui->numbedit->clear();ui->nameedit->clear();ui->sexedit->clear();ui->scoreedit->clear();return;}else{QMessageBox::information(this,"提示","更改排序失败");query.lastError();return;}}