Qt5中创建临时的后台线程。

有个需求就是，GUI图形界面在上传文件到服务器的时候，需要用zip命令行打包，因为文件很多的时候，zip命令打包需要计算很长时间，所以把这样计算量大的任务分离到后台线程比较合适，然后任务完成，以信号槽机制来通知前台

UI线程处理结果。所以这个线程是需要销毁的，跟之前的一直在运行的后台线程接收网络数据的不一样。

压缩文件的任务类 H文件：

 #include <QObject>

 #include <QStringList>

 class ZipUpdatePackageTask : public QObject

 {

     Q_OBJECT

 public:

     ZipUpdatePackageTask();

     ~ZipUpdatePackageTask();

 public slots:

     void doZip();

     void beZipFiles(const QStringList& files);

 signals:

     void zipFinished();

     void zipPackageInfo(const QString& fileName, const QString& md5, const QString& size);

 private:

     bool beZipFilesIsEmpty();

     void deleteHistoryZip(const QString& targetPackage);

     void toBeZipFilesArguments(QString &files);

     void startZipTask(QString zipExePath, QString targetPackage, QString files);

     QString getFileMD5(const QString& targetZipPackage);

     QString getFileSize(const QString& targetZipPackage);

 private:

     QStringList m_files;

 };

压缩任务类的 cpp文件：

 #include <QCoreApplication>

 #include <QFile>

 #include <QFileInfo>

 #include <QDir>

 #include <QProcess>

 #include <QCryptographicHash>

 ZipUpdatePackageTask::ZipUpdatePackageTask()

 {

 }

 ZipUpdatePackageTask::~ZipUpdatePackageTask()

 {

 }

 void ZipUpdatePackageTask::doZip()

 {

     QString appDir = qApp->applicationDirPath();

     QString zipExePath = QString("%1/%2").arg(appDir).arg("zip.exe");

     if (QFile::exists(zipExePath) && !beZipFilesIsEmpty())

     {

         QString targetZipPackage = QString("%1/%2").arg(appDir).arg("update.zip");

         QString beZipFiles;

         toBeZipFilesArguments(beZipFiles);

         deleteHistoryZip(targetZipPackage);

         startZipTask(zipExePath, targetZipPackage, beZipFiles);

         if (QFile::exists(targetZipPackage))

         {

             QString size = getFileSize(targetZipPackage);

             QString md5 = getFileMD5(targetZipPackage);

             emit zipPackageInfo(targetZipPackage, md5, size);

         }

     }

     emit zipFinished();

 }

 void ZipUpdatePackageTask::beZipFiles(const QStringList& files)

 {

     m_files.clear();

     m_files = files;

 }

 bool ZipUpdatePackageTask::beZipFilesIsEmpty()

 {

     return m_files.isEmpty();

 }

 void ZipUpdatePackageTask::deleteHistoryZip(const QString& targetPackage)

 {

     if (QFile::exists(targetPackage))

     {

         QDir dir;

         dir.remove(targetPackage);

     }

 }

 void ZipUpdatePackageTask::toBeZipFilesArguments(QString &files)

 {

     for (auto file : m_files)

     {

         files.append(file);

         files.append(" ");

     }

 }

 void ZipUpdatePackageTask::startZipTask(QString zipExePath, QString targetPackage, QString files)

 {

     QProcess* zipProcesss = new QProcess;

     //zip a [zip_package_path_name] [file1Path]...[fileNPath]

     QString command = QString("%1 a %2 %3").arg(zipExePath).arg(targetPackage).arg(files);

     zipProcesss->start(command);

     zipProcesss->waitForFinished(-);

 }

 QString ZipUpdatePackageTask::getFileMD5(const QString& targetZipPackage)

 {

     QString md5;

     QFile file(targetZipPackage);

     if (file.open(QFile::ReadOnly))

     {

         QCryptographicHash hash(QCryptographicHash::Md5);

         if (hash.addData(&file))

         {

             md5 = QString(hash.result().toHex());

         }

         file.close();

     }

     return md5;

 }

 QString ZipUpdatePackageTask::getFileSize(const QString& targetZipPackage)

 {

     QFileInfo fileInf(targetZipPackage);

     return QString::number(fileInf.size());

 }

以下是创建这个后台压缩线程的槽函数，当压缩上传的button点击，就调用以下这个槽函数:

 void StatisticsWidget::slotUploadPackage()

 {

     QThread *zipThread = new QThread;

     ZipUpdatePackageTask* task = new ZipUpdatePackageTask();

     QStringList beZipFiles;

     for (int listRow = ; listRow < ui->updateFileList->count(); ++listRow)

     {

         beZipFiles << ui->updateFileList->item(listRow)->text();

     }

     task->beZipFiles(beZipFiles);

     task->moveToThread(zipThread);

     connect(zipThread, &QThread::started, task, &ZipUpdatePackageTask::doZip);

     connect(task, SIGNAL(zipFinished()), zipThread, SLOT(quit()));

     connect(task, &ZipUpdatePackageTask::zipPackageInfo, this, &StatisticsWidget::slotZipFinished,Qt::QueuedConnection);

     //automatically delete thread and task object when work is done:

     connect(zipThread, SIGNAL(finished()), task, SLOT(deleteLater()));

     connect(zipThread, SIGNAL(finished()), zipThread, SLOT(deleteLater()));

     zipThread->start();

 }

注意，以上代码都是临时任务和线程，当任务完成以后，由于设置了相应的信号槽，会自动删除。任务线程做完该做的事儿，发出了一个zipPackageInfo的信号就销毁了。UI线程只用编写一个槽函数来接收做完的信号并处理就可以了。

巴特西

Qt5中创建临时的后台线程。

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