Qt实现FTP的上传和下载的实例代码

#-------------------------------------------------
#
# Project created by QtCreator 2015-10-29T23:52:56
#
#-------------------------------------------------
QT += core gui
QT += network #这里要添加这个库
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = QFtp
TEMPLATE = app
SOURCES += main.cpp
 dialog.cpp
HEADERS += dialog.h

#ifndef DIALOG_H
#define DIALOG_H
//注意需要添加的头文件
#include<QDialog>
#include<QPushButton>
#include<QFile>
#include<QNetworkReply>
#include<QLineEdit>
#include<QtNetwork/QNetworkAccessManager>
#include<QtNetwork/QNetworkRequest>
#include<QLabel>
#include<QString>
#include<QGridLayout>
#include<QMessageBox>
class Dialog : public QDialog
{
 Q_OBJECT
public:
 Dialog(QWidget *parent = 0);
 ~Dialog();
public:
 QGridLayout *layout;
 QLabel *LbServer,*LbUser,*LbPasswd;
 QLineEdit *LeServer,*LeUser,*LePasswd;
 QPushButton *PbPut,*PbGet;
 QNetworkAccessManager manager;//这个是重点
protected slots:
 //处理按钮的点击信号
 void slotPut();
 void slotGet();
 //处理网络连接的信号
 void managePut(QNetworkReply*);
 void manageGet(QNetworkReply*);
};
#endif // DIALOG_H

#include "dialog.h"
Dialog::Dialog(QWidget *parent)
 : QDialog(parent)
{
 setWindowTitle("My Ftp");
 layout=new QGridLayout(this);
 LbServer=new QLabel("Server:");
 LbUser=new QLabel("User:");
 LbPasswd=new QLabel("Passwd:");
 LeServer=new QLineEdit("ftp://120.27.41.126/home/myths/1.txt");
 LeUser=new QLineEdit("myths");
 LePasswd=new QLineEdit("123456");
 LePasswd->setEchoMode(QLineEdit::Password);//设置加密显示
 PbPut=new QPushButton("Put");
 PbGet=new QPushButton("Get");
 layout->addWidget(LbServer,0,0);
 layout->addWidget(LeServer,0,1);
 layout->addWidget(LbUser,1,0);
 layout->addWidget(LeUser,1,1);
 layout->addWidget(LbPasswd,2,0);
 layout->addWidget(LePasswd,2,1);
 layout->addWidget(PbPut,3,0);
 layout->addWidget(PbGet,3,1);
 setFixedSize(300,200);//固定大小
 //按钮点击事件信号槽的连接
 connect(PbPut,SIGNAL(clicked()),this,SLOT(slotPut()));
 connect(PbGet,SIGNAL(clicked()),this,SLOT(slotGet()));
}
void Dialog::managePut(QNetworkReply * reply){
 qDebug()<<reply->error();//输出调试信息
 switch(reply->error()){//判断连接后的状态
 case QNetworkReply::NoError:
 QMessageBox::information(this,"Put information","Upload Success!");
 break;
 case QNetworkReply::HostNotFoundError:
 QMessageBox::information(this,"Put information","Host Not Found!");
 break;
 case QNetworkReply::AuthenticationRequiredError:
 QMessageBox::information(this,"Put information","Login Failure!");
 break;
 default:
 QMessageBox::information(this,"Put information","Unknown Failure");
 break;
 }
}
void Dialog::manageGet(QNetworkReply *reply){
 //基本和managerPut类似 
 qDebug()<<reply->error();
 QByteArray data;
 switch(reply->error()){
 case QNetworkReply::NoError:
 data=reply->readAll();//从url中读取文件内容，输出到data中（也可以再将数据写入到文件中，为了方便，这里就权且打印一下吧）
 QMessageBox::information(this,"Put information","Upload Success!nThe file you've got is :n"+data);
 break;
 case QNetworkReply::HostNotFoundError:
 QMessageBox::information(this,"Put information","Host Not Found!");
 break;
 case QNetworkReply::AuthenticationRequiredError:
 QMessageBox::information(this,"Put information","Login Failure!");
 break;
 default:
 QMessageBox::information(this,"Put information","Unknown Failure");
 break;
 }
}
Dialog::~Dialog()
{
}
void Dialog::slotPut(){
 //判断信息输入完整
 if(LeUser->text().isEmpty()||LePasswd->text().isEmpty()||LeServer->text().isEmpty()){
 QMessageBox::warning(this,"Error","Please fill in the information");
 return ;
 }
 //重点！将之前的槽清空并重新连接至需要的
 manager.disconnect(SIGNAL(finished(QNetworkReply*)));
 //完全清空某对象连接的槽可以用manager.disconnect();
 connect(&manager,SIGNAL(finished(QNetworkReply*)),SLOT(managePut(QNetworkReply*)));
 //设置登录信息
 QUrl url(LeServer->text());
 url.setPort(21);
 url.setUserName(LeUser->text());
 url.setPassword(LePasswd->text());
 QByteArray data="This is the test data.n";
 /*QNetworkReply *reply=*/
 manager.put(QNetworkRequest(url),data);//将data上传到url中，返回的reply将触发网络的连接信号
}
void Dialog::slotGet(){
 //基本意义与slotPut类似
 if(LeUser->text().isEmpty()||LePasswd->text().isEmpty()||LeServer->text().isEmpty()){
 QMessageBox::warning(this,"Error","Please fill in the information");
 return ;
 }
 manager.disconnect(SIGNAL(finished(QNetworkReply*)));
 connect(&manager,SIGNAL(finished(QNetworkReply*)),SLOT(manageGet(QNetworkReply*)));
 QUrl url(LeServer->text());
 url.setPort(21);
 url.setUserName(LeUser->text());
 url.setPassword(LePasswd->text());
 /*QNetworkReply *reply=*/
 manager.get((QNetworkRequest(url)));
}

#include "dialog.h"
#include <QApplication>
int main(int argc, char *argv[])
{
 QApplication a(argc, argv);
 Dialog w;
 w.show();
 return a.exec();
}