C#线程系列讲座(3)：线程池和文件下载服务器

private   static   void  execute( object  state)
{
    Console.WriteLine(state);      
}
static   void  Main( string [] args)
{
  
     int  workerThreads;
     int  completionPortThreads;
         
    ThreadPool.GetMaxThreads( out  workerThreads,  out  completionPortThreads);
    Console.WriteLine(workerThreads);
    Console.WriteLine(completionPortThreads);    
    ThreadPool.QueueUserWorkItem(execute, " 线程1 " );    //  从线程池中得到一个线程，并运行execute
    ThreadPool.QueueUserWorkItem(execute,  " 线程2 " );
    ThreadPool.QueueUserWorkItem(execute,  " 线程3 " );
    Console.ReadLine();
}

using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Text;
using  System.Threading;
using  System.Net.Sockets;
using  System.IO;

namespace  MyThread
{
     class  FileServer
    {
         private  String root;
         private  Thread listenerThread;

         private   void  worker( object  state)
        {
             TcpClient client  =  state  as  TcpClient;
              try
             {

                 client.ReceiveTimeout  =   2000 ;
                 Stream stream  =  client.GetStream();
                 System.IO.StreamReader sr  =   new  StreamReader(stream);
                 String line  =  sr.ReadLine();
                 String[] array  =  line.Split( '   ' );
                 String path  =  array[ 1 ].Replace( ' / ' ,  ' \\ ' );
                 String filename  =  root  +  path;
                  if  (File.Exists(filename))   //  如果下载文件存在，开始下载这个文件
                 {
                     FileStream fileStream  =   new  FileStream(filename, FileMode.Open, FileAccess.Read, 
                                                           FileShare.Read);
                      byte [] buffer  =   new   byte [ 8192 ];  //  每次下载8K
                      int  count  =   0 ;
                     String responseHeader  =   " HTTP/1.1 200 OK\r\n "   +
                                              " Content-Type:application/octet-stream\r\n "   +
                                              " Content-Disposition:attachment;filename= "   +
                                                   filename.Substring(filename.LastIndexOf( " \\ " )  +   1 )  +   " \r\n\r\n " ;
                      byte [] header  =  ASCIIEncoding.ASCII.GetBytes(responseHeader);
                     stream.Write(header,  0 , header.Length);
                      while  ((count  =  fileStream.Read(buffer,  0 , buffer.Count()))  >   0 )
                     {
                         stream.Write(buffer,  0 , count);
                     }
                     Console.WriteLine(filename  +   " 下载完成 " );
                 }
                  else    //  文件不存在，输出提示信息
                 {
                     String response  =   " HTTP/1.1 200 OK\r\nContent-Type:text/plain;charset=utf-8\r\n\r\n文件不存在 " ;
                      byte [] buffer  =  ASCIIEncoding.UTF8.GetBytes(response);
                     stream.Write(buffer,  0 , buffer.Length);
                 }

             }
              catch  (Exception e)
             {
                 Console.WriteLine(e.Message);
             }
              finally
             {
                  if  (client  !=   null )
                 {
                     client.Close();
                 }
             }
        }

         private   void  listener()
        {
            TcpListener listener  =   new  TcpListener( 1234 );
            listener.Start();   //  开始监听客户端请求
            TcpClient client  =   null ;

             while  ( true )
            {
                client  =  listener.AcceptTcpClient();
                client.ReceiveTimeout  = 2000 ;
                ThreadPool.QueueUserWorkItem(worker, client);   //  从线程池中获得一个线程来处理客户端请求
            }
        }
         public  FileServer(String root)
        {
             this .root =  root;         
        }
         public   void  start()
        {
            listenerThread  =   new  Thread(listener);
            listenerThread.Start();   //  开始运行监听线程
        }
    }
}