Qt中多线程使用案列

Qt中多线程下载大文件

#pragma once

#include 
#include 
#include "ThreadPool.h"
#include 
#include 
#include 
#include 
class MainWindow : public QWidget
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = Q_NULLPTR);

private:
   
	void initUI();

	void initConnect();

private:


	QPushButton*  m_dlBtn;
	DownLoad::ThreadPool  threadPool;
	QMap<QString ,std::pair<QLabel*,QProgressBar*> > controlMap;

};

#include "MainWindow.h"

#include "Task.h"
#include "ThreadPool.h"
MainWindow::MainWindow(QWidget *parent)
	: QWidget(parent)
{
	initUI();
	initConnect();
}

void MainWindow::initUI()
{
	m_dlBtn = new QPushButton(this);
	m_dlBtn->setText(QString("DownLoad"));
	QVBoxLayout*  layout = new QVBoxLayout();
	layout->setSpacing(10);
	layout->setContentsMargins(10, 10, 10, 10);
	layout->addWidget(m_dlBtn);
	


	for (int i = 0; i < 10; i++)
	{
		DownLoad::Task* task = new DownLoad::Task("http://mirrors.tuna.tsinghua.edu.cn/archlinux/iso/2023.12.01/archlinux-2023.12.01-x86_64.iso", QString("C:/Users/gd09861-hlw/Desktop/11111/archlinux-2023.12.01-x86_64_%1.iso").arg(i), DownLoad::Task::WorkModel::DOWNLOAD);
		threadPool.push(task);
		QLabel *label = new QLabel(this);
		label->setText(QString("%1").arg(i));
		QProgressBar *progressBar = new QProgressBar(this);
		controlMap.insert(task->id(), std::make_pair(label, progressBar));

		QHBoxLayout *hLayout = new QHBoxLayout;
		hLayout->addWidget(label);
		hLayout->addWidget(progressBar);
		layout->addLayout(hLayout);
	}
	this->setLayout(layout);
}

void MainWindow::initConnect()
{
	connect(m_dlBtn, &QPushButton::clicked, [&]() {
			
			threadPool.startAll();
		

		}


	);
	connect(&threadPool, &DownLoad::ThreadPool::sigUpdateTaskProgress, this, [&](QString id, qint64 bytesR, qint64 bytesT) {

		controlMap[id].second->setValue((bytesR*100.0f) / (bytesT*1.0f));
	
	});

	connect(&threadPool, &DownLoad::ThreadPool::sigUpdateTaskState, this, [&](QString id,DownLoad::Task::State state) {
		switch (state)
		{
		case DownLoad::Task::Start:
		{
			controlMap[id].second->setValue(0);
		}
			break;
		case DownLoad::Task::Stop: {
			controlMap[id].first->setText("Stop");
		}
			break;
		case DownLoad::Task::Finish:
			controlMap[id].first->setText("Finish");
			break;
		case DownLoad::Task::Error:
			controlMap[id].first->setText("error");
			break;
		default:
			break;
		}
	});
}

#ifndef  __TASK_QUEUE_H__
#define  __TASK_QUEUE_H__

#include 
#include 
#include "Task.h"
#include 
#include 
namespace DownLoad {

#define  DEFAULT_THREAD_MAX_COUNT  3
	class ThreadPool :public QObject
	{
		Q_OBJECT
	public:


		ThreadPool();
		~ThreadPool();

		void init();
		void  push(Task *task);
		Task* pop();
		void startAll();
		void slotUpdateTaskState(QString id, Task::State  state);
		signals :
				void sigUpdateTaskProgress(QString id, qint64 bytesReceived, qint64 bytesTotal);
				void sigUpdateTaskState(QString id, Task::State  state);
	private:

		QQueue<Task*>  m_tasks;
	
		QList<QThread*>  m_threads;
	};
};
#endif

#include "ThreadPool.h"
#include 
#include 
#include "Task.h"
DownLoad::ThreadPool::ThreadPool()
{
	init();
}

DownLoad::ThreadPool::~ThreadPool()
{

}

void DownLoad::ThreadPool::init()
{
	for (int i = 0; i < DEFAULT_THREAD_MAX_COUNT; i++) {
		QThread  *thread = new QThread();
		m_threads.push_back(thread);
	}
}


void DownLoad::ThreadPool::push(Task *task)
{
	
	m_tasks.enqueue(task);
}

DownLoad::Task* DownLoad::ThreadPool::pop()
{
	
	return m_tasks.dequeue();
}

void DownLoad::ThreadPool::startAll()
{
	if (m_threads.isEmpty()) {
		return;
	}

	for (int i = 0; i < m_threads.count(); i++)
	{
		QThread *  thread = m_threads.at(i);
		if (thread->isRunning()) {
			continue;
		}
		if (m_tasks.isEmpty()) {
			return;
		}
		Task* task = pop();
		task->moveToThread(thread);
	
		connect(task, &Task::sigUpdateProgress, this, &ThreadPool::sigUpdateTaskProgress, Qt::QueuedConnection);
		connect(task, &Task::sigUpdateState, this, &ThreadPool::slotUpdateTaskState, Qt::QueuedConnection);
		connect(thread, &QThread::started, task, &Task::slotDoWork,Qt::QueuedConnection);
		connect(thread, &QThread::finished, task, &Task::deleteLater);
		thread->start();

	}
}

void DownLoad::ThreadPool::slotUpdateTaskState(QString id, Task::State  state)
{
	emit  sigUpdateTaskState(id, state);

	if (state == DownLoad::Task::Finish || state == DownLoad::Task::Error||state==DownLoad::Task::Stop) {
	
		startAll();
	}
}

#ifndef  __TASK_H__
#define  __TASK_H__

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
namespace  DownLoad {
#define  DOWNLOAD_FILE_SUFFIX  ".tmp"

	

	class Task :public QObject
	{
		Q_OBJECT
	public:
			enum WorkModel
		{
			UPLOAD,
			DOWNLOAD,
		};

		enum State
		{
			Start,
			Stop,
			Finish,
			Error,
		};
	
		QString  id();
		Task(const QString &strUrl, const QString &filePath, const WorkModel& workModel);
		~Task();
		void setSupportBreakPoint(bool isSupport);
		QString lastError();
	signals:


		void sigUpdateState(QString id,State  state);
		void sigUpdateProgress(QString id,qint64 bytesReceived, qint64 bytesTotal);
		public slots:

		void slotDoWork();

		void slotStopWork();

		void slotCancelWork();


	protected:
		void removeTmpFile(const QString &filePath);
		void slotUpdateProgress(qint64 bytesReceived, qint64 bytesTotal);
		void slotWriteFile();
		void slotFinish();
		void slotError(QNetworkReply::NetworkError code);
	protected:
		void doDownWork();
		void doUploadWork();
	private:


		QNetworkReply*				 m_reply = nullptr;
		QNetworkRequest				 m_request;
		QNetworkAccessManager		 m_manager;
		QUrl m_url;
		QString m_filePath = "";
		WorkModel  m_workModel = UPLOAD;
		QSharedPointer<QEventLoop>  m_loop;
		bool m_bSupportBPoint = false;
		qint64  m_bytesReceived;
		qint64  m_bytesTotal;
		qint64  m_bytesCurrentReceived;
		QString m_error = "";
		QString m_id = "";
	};
	
};
Q_DECLARE_METATYPE(DownLoad::Task::State);

#endif     //__TASK_H__

#include "Task.h"
#include 
#include 
#include 
#include 
#include 


QString DownLoad::Task::id()
{
	return m_id;
}

DownLoad::Task::Task(const QString &strUrl, const QString &filePath, const WorkModel& workModel)
	:QObject(nullptr), m_url(strUrl), m_filePath(filePath), m_workModel(workModel),m_bytesTotal(0)
	,m_bytesReceived(0),m_bytesCurrentReceived(0),m_bSupportBPoint(false),m_id(QUuid::createUuid().toString())
{

}



DownLoad::Task::~Task()
{
	if (m_reply) {
		m_reply->deleteLater();
	}

}



void DownLoad::Task::setSupportBreakPoint(bool isSupport)
{
	m_bSupportBPoint = isSupport;
}

QString DownLoad::Task::lastError()
{
	return m_error;
}

void DownLoad::Task::slotDoWork()
{
	qDebug() << "UUID:" << m_id << "TID:" << QThread::currentThreadId()<<"\t"<<m_filePath;
	if (m_url.isEmpty() || m_filePath.isEmpty()) {
		return;
	}
	switch (m_workModel)
	{
	case DownLoad::Task::UPLOAD:
		doUploadWork();
		break;
	case DownLoad::Task::DOWNLOAD:
		doDownWork();
		break;
	default:
		break;
	}
}



void DownLoad::Task::slotStopWork()
{
	m_bytesCurrentReceived += m_bytesReceived;
	if (m_reply) {
		disconnect(m_reply, 0, this, 0);
		m_reply->abort();
		m_reply->deleteLater();
		m_reply = nullptr;
		this->thread()->exit();
		emit  sigUpdateState(m_id,State::Stop);
	}
}

void DownLoad::Task::slotCancelWork()
{
	slotStopWork();
	m_bytesCurrentReceived = 0;
	m_bytesReceived = 0;
	m_bytesTotal = 0;
	removeTmpFile(m_filePath + DOWNLOAD_FILE_SUFFIX);
}

void DownLoad::Task::removeTmpFile(const QString &filePath)
{
	QFileInfo fileInfo(filePath);
	if (fileInfo.exists()) {
		QFile::remove(filePath);
	}
}

void DownLoad::Task::slotUpdateProgress(qint64 bytesReceived, qint64 bytesTotal)
{
	m_bytesReceived = bytesReceived;
	m_bytesTotal = bytesTotal;
	emit  sigUpdateProgress(m_id,m_bytesReceived + m_bytesCurrentReceived, m_bytesTotal + m_bytesCurrentReceived);
}

void DownLoad::Task::slotWriteFile()
{
	QFile file(m_filePath + DOWNLOAD_FILE_SUFFIX);
	QDir dir=QFileInfo(m_filePath + DOWNLOAD_FILE_SUFFIX).absoluteDir();
	if (!dir.exists()) {
		dir.mkpath(dir.absolutePath());
	}
	if (file.open(QIODevice::WriteOnly | QIODevice::Append)) {
		file.write(m_reply->readAll());
	}
	file.close();
}

void DownLoad::Task::slotFinish()
{
	QVariant  code = m_reply->attribute(QNetworkRequest::HttpStatusCodeAttribute);
	qDebug() << "Error Code:" << code.toInt();
	if (m_reply->error() == QNetworkReply::NoError) {
		QFileInfo fileInfo(m_filePath + DOWNLOAD_FILE_SUFFIX);
		if (fileInfo.exists()) {
			QFile::rename(m_filePath+DOWNLOAD_FILE_SUFFIX,m_filePath);
			this->thread()->exit();
			emit sigUpdateState(m_id, State::Finish);
		}
	}
	else { 
		m_error = m_reply->errorString();
		this->thread()->exit();
		emit sigUpdateState(m_id, State::Error);
	}
}

void DownLoad::Task::slotError(QNetworkReply::NetworkError code)
{
	if (code == QNetworkReply::NoError)
		return;
	slotStopWork();
	removeTmpFile(m_filePath + DOWNLOAD_FILE_SUFFIX);
	this->thread()->exit();
	emit	 sigUpdateState(m_id, State::Error);
	m_error = m_reply->errorString();
	

}

void DownLoad::Task::doDownWork()
{
	
	if (m_bytesCurrentReceived <= 0) {
		removeTmpFile(m_filePath + DOWNLOAD_FILE_SUFFIX);
	}
	QFileInfo  fileInfo(m_filePath + DOWNLOAD_FILE_SUFFIX);
	if (fileInfo.exists()) {
		m_bytesCurrentReceived = fileInfo.size();
	}
	QString strUrl = m_url.toString();

	m_request.setUrl(strUrl);
	if (m_bSupportBPoint) {
		QString strRange = QString("bytes=%1-").arg(m_bytesCurrentReceived);
		m_request.setRawHeader("Range", strRange.toLatin1());
	}

	m_reply = m_manager.get(m_request);
	connect(m_reply, &QNetworkReply::downloadProgress, this, &Task::slotUpdateProgress);
	connect(m_reply, &QNetworkReply::readyRead, this, &Task::slotWriteFile);
	connect(m_reply, &QNetworkReply::finished, this, &Task::slotFinish);
	connect(m_reply, SIGNAL(error(QNetworkReply::NetworkError code)), this,SLOT(slotError(QNetworkReply::NetworkError code)));
}

void DownLoad::Task::doUploadWork()
{
		
}

上处代码运行可以看出，QThread 中,每次调用start() 时 ，都会改变线程ID
因此，QT 的线程开启就是在创建线程，只不过其中含有事件循环机制。另外对于自定义类型，必须指定队列连接。
运行后