[C++知识库]Qt-Qt版本线程池实现

#pragma once
#include <QList>
#include <QThread>
#include "Worker.h"
#include <QObject>

class ThreadPool: public QObject
{
    Q_OBJECT
public:
    ThreadPool(int size);
    ~ThreadPool();

    static ThreadPool* getInstance();//默认5个线程
    void addTask(std::function<void()> task, int index = -1);

private:
    int size;
    QList<QThread*> threadPool;
    int threadIndex;
};

#include "ThreadPool.h"
#include <QThread>
#include "Worker.h"

ThreadPool::ThreadPool(int size): threadIndex(0), size(size)
{
    for (int i = 0; i < size; i++)
    {
        QThread* thread = new QThread;
        thread->start();
        threadPool << thread;
    }
}

ThreadPool::~ThreadPool()
{
    for (int i = 0; i < threadPool.size(); i++)
    {
        threadPool[i]->exit();
        threadPool[i]->wait();//必须，否则可能未退出就被delete
        delete threadPool[i];
    }
}

ThreadPool* ThreadPool::getInstance()
{
    static ThreadPool m_instance(5);
    return &m_instance;
}

void ThreadPool::addTask(std::function<void()> task, int index)
{
    //任务分配
    Worker* worker = new Worker;
    QThread* thread = nullptr;
    connect(worker, &Worker::workDone, worker, &Worker::deleteLater);
    worker->addTask(task);

    if (index == -1)
    {
        thread = threadPool[threadIndex];
        threadIndex = (threadIndex + 1) % size;
    }
    else
    {
        thread = threadPool[index % size];
    }

    //任务运行
    worker->moveToThread(thread);
    QMetaObject::invokeMethod(worker, "startTask", Qt::QueuedConnection);
}

#pragma once

#include <QThread>
#include <functional>
#include <QMutex>

class Worker : public QObject
{
    Q_OBJECT

public:
    Worker(QObject* parent = nullptr);
    ~Worker();

    void addTask(std::function<void()> task);

signals:
    void workDone();

private slots :
    void startTask();

private:
    QList<std::function<void()>> taskList;
    QMutex mutex;
};

#include "Worker.h"
#include <QThread>
#include <QObject>
#include <QMutexLocker>
#include <QDebug>

Worker::Worker(QObject* parent)
    : QObject(parent)
{
}

Worker::~Worker()
{
}

void Worker::addTask(std::function<void()> task)
{
    QMutexLocker lock(&mutex);
    taskList << task;
}

void Worker::startTask()
{
    qDebug() << "start Worker" << thread();
    QMutexLocker lock(&mutex);
    std::function<void()> task;

    if (!taskList.isEmpty())
    {
        task = taskList.first();
        lock.unlock();
        task();
        qDebug() << "done Worker" << thread();
    }
}

用法

//同一个线程中顺序执行
ThreadPool::getInstance()->addTask([]()
{
    QThread::sleep(3);
}, 0);
ThreadPool::getInstance()->addTask([]()
{
    QThread::sleep(3);
}, 0);
//不指定线程执行
ThreadPool::getInstance()->addTask([]()
{
    QThread::sleep(10);
});
ThreadPool::getInstance()->addTask([]()
{
    QThread::sleep(10);
});