自已写的线程池

C#有ThreadPool和Task，为什么还要自己写线程池？我以前也没想过自己写线程池，都是用ThreadPool或Task，前段时间写爬虫，我想控制10个线程爬网页、10个线程下载网页上的图片，不然的话因为网页很多，图片相对较少，可能大部分线程都在爬网页，少量线程在下载图片，这样下载图片的速度慢了，所以我想到了自己写线程池MyThreadPool，再配合ThreadPool使用，精确控制爬网页和下载图片的线程数。不过这个线程池写的比较简单，缺点是线程池会瞬间创建最大数量的工作线程。

线程池类代码：

using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;

namespace Utils
{
    /// <summary>
    /// 线程池
    /// </summary>
    public static class MyThreadPool
    {
        /// <summary>
        /// 最大工作线程数
        /// </summary>
        private static int m_WorkerThreads = 5;
        /// <summary>
        /// 线程队列
        /// </summary>
        private static ConcurrentQueue<MyThread> m_ThreadQueue = new ConcurrentQueue<MyThread>();
        /// <summary>
        /// 任务队列
        /// </summary>
        private static ConcurrentQueue<Tuple<Action<object>, object>> m_Action = new ConcurrentQueue<Tuple<Action<object>, object>>();

        /// <summary>
        /// 创建并启动线程
        /// </summary>
        /// <param name="action"></param>
        /// <param name="obj"></param>
        public static void Start(Action<object> action, object obj = null)
        {
            m_Action.Enqueue(new Tuple<Action<object>, object>(action, obj));

            MyThread thread;
            if (m_ThreadQueue.Count < m_WorkerThreads)
            {
                thread = new MyThread();
                m_ThreadQueue.Enqueue(thread);
                thread.isWorker = true; //设置为工作线程
                thread.thread = new Thread(new ThreadStart(() =>
                {
                    Tuple<Action<object>, object> tuple;
                    while (thread.isWorker) //如果是工作线程，则一直循环
                    {
                        if (m_Action.TryDequeue(out tuple)) //如果任务队列中有任务，则取出任务执行
                        {
                            tuple.Item1(tuple.Item2); //执行任务
                        }
                        else
                        {
                            Thread.Sleep(100);
                        }
                        Thread.Sleep(1);
                    }
                }));
                thread.thread.IsBackground = true;
                thread.thread.Start();
            }
        }

        /// <summary>
        /// 设置最大工作线程数
        /// </summary>
        /// <param name="workerThreads">最大工作线程数</param>
        public static void SetMaxThreads(int workerThreads)
        {
            m_WorkerThreads = workerThreads;
            MyThread thread = null;
            while (m_ThreadQueue.Count > m_WorkerThreads)
            {
                m_ThreadQueue.TryDequeue(out thread);
                thread.isWorker = false;
                Thread.Sleep(1);
            }
        }

        /// <summary>
        /// 获取最大工作线程数
        /// </summary>
        public static int GetMaxThreads()
        {
            return m_WorkerThreads;
        }

        /// <summary>
        /// 获取当前工作线程数
        /// </summary>
        public static int GetWorkerThreads()
        {
            return m_ThreadQueue.Count;
        }
    }

    /// <summary>
    /// 线程
    /// </summary>
    public class MyThread
    {
        /// <summary>
        /// 线程
        /// </summary>
        public Thread thread { get; set; }
        /// <summary>
        /// 是否工作线程
        /// </summary>
        public bool isWorker { get; set; }
    }
}

测试代码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;
using Common.Utils;
using System.Collections.Concurrent;

namespace test
{
    public partial class Form1 : Form
    {
        private static int errorCount = 0;
        private static int errorCount2 = 0;
        private static object _lock = new object();
        private static int dataCount = 30;
        /// <summary>
        /// 任务执行总次数
        /// </summary>
        private static int runCount = 0;

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            ThreadPool.SetMaxThreads(20, 20);
            StringBuilder sb = new StringBuilder();
            for (int k = 1; k <= dataCount; k++)
            {
                sb.AppendFormat("{0},", k.ToString("00"));
            }
            lblMsg2.Text = sb.ToString();

            timer1.Tick += new EventHandler((obj, ea) =>
            {
                int maxThreads = MyThreadPool.GetMaxThreads();
                int workerThreads = MyThreadPool.GetWorkerThreads();
                lblMsg.Text = string.Format("{0}/{1}(工作线程数/最大工作线程数)", workerThreads, maxThreads);
                //ThreadPool.GetMaxThreads(out workerThreads, out maxThreads);
                //lblMsg.Text = string.Format("{0}/{1}(最大辅助线程数/最大I/O线程数)", workerThreads, maxThreads);

                if (workerThreads > maxThreads)
                {
                    errorCount++;
                    lblError.Text = "错误(工作线程数超过最大工作线程数)次数：" + errorCount.ToString() + "，错误(线程内代码执行结果错误)次数：" + errorCount2.ToString();
                }
                if (lblMsg2.Text != sb.ToString())
                {
                    errorCount2++;
                    lblError.Text = "错误(工作线程数超过最大工作线程数)次数：" + errorCount.ToString() + "，错误(线程内代码执行结果错误)次数：" + errorCount2.ToString();
                    LogUtil.LogError(lblMsg2.Text);
                }
                lblRunCount.Text = "任务执行总次数：" + runCount.ToString();
            });
            timer1.Interval = 100;
            timer1.Start();
            lblError.Text = "暂没有错误";
        }

        //开始
        private void button1_Click(object sender, EventArgs e)
        {
            MyThreadPool.SetMaxThreads(20);
            ThreadPool.SetMaxThreads(20, 20);
            button1.Enabled = false;
            Thread thread = new Thread(new ThreadStart(() =>
            {
                while (true)
                {
                    List<int> list = new List<int>();
                    for (int i = 1; i <= dataCount; i++)
                    {
                        // ThreadPool.QueueUserWorkItem((obj) =>
                        // Task.Factory.StartNew((obj) =>
                        MyThreadPool.Start((obj) =>
                        {
                            int n = (int)obj;
                            lock (_lock)
                            {
                                list.Add(n);
                            }
                            if (list.Count == dataCount)
                            {
                                list.Sort();
                                StringBuilder sb = new StringBuilder();
                                for (int k = 0; k < list.Count; k++)
                                {
                                    sb.AppendFormat("{0},", list[k].ToString("00"));
                                }
                                this.Invoke(new MyInvoke(() => { lblMsg2.Text = sb.ToString(); }));
                                runCount++;
                            }
                        }, i);
                    }
                    Thread.Sleep(1);
                }
            }));
            thread.IsBackground = true;
            thread.Start();
        }

        //设置最大工作线程数
        private void button2_Click(object sender, EventArgs e)
        {
            int d;
            if (int.TryParse(txtMaxThreads.Text, out d))
            {
                if (d > 0)
                {
                    MyThreadPool.SetMaxThreads(d);
                    ThreadPool.SetMaxThreads(d, d);
                }
                else
                {
                    txtMaxThreads.Text = "1";
                }
            }
            else
            {
                txtMaxThreads.Text = "20";
            }
        }

    }

    public delegate void MyInvoke();
}

测试截图：