C#实现http协议下的多线程文件传输

                 1
                public
                 System.Windows.Forms.ListBox listBox1;  

                 2
                private
                 System.Windows.Forms.Label label1;  

                 3
                private
                 System.Windows.Forms.TextBox textBox1  

                 4
                private
                 System.Windows.Forms.Button button1;  

                 5
                private
                 System.Windows.Forms.Label label2;  

                 6
                private
                 System.Windows.Forms.TextBox textBox2;  

                 7
                private
                 System.Windows.Forms.Label label3;  

                 8
                private
                 System.Windows.Forms.TextBox textBox3;  

                 9
                private
                 System.Windows.Forms.Label label4;  

                10
                private System.Windows.Forms.TextBox textBox4; 

                  1
                public
                class
                 HttpFile  

                  2
                    {  

                  3
                public
                 Form1 formm;  

                  4
                public
                int threadh;//线程代号    5publicstring filename;//文件名    6publicstring strUrl;//接收文件的URL    7public FileStream fs;  
  8public HttpWebRequest request;  
  9public System.IO.Stream ns;  
 10publicbyte[] nbytes;//接收缓冲区   11publicint nreadsize;//接收字节数   12public HttpFile(Form1 form,int thread)//构造方法   13    　{  
 14     formm=form;  
 15     threadh=thread;  
 16    　}  
 17     　~HttpFile()//析构方法   18    　{  
 19    formm.Dispose ();  
 20    　}  
 21publicvoid receive()//接收线程   22    　{  
 23     filename=formm.filenamew[threadh];  
 24     strUrl=formm.strurl;  
 25     ns=null;  
 26     nbytes= newbyte[512];  
 27     nreadsize=0;  
 28     formm.listBox1 .Items .Add ("线程"+threadh.ToString ()+"开始接收");  
 29     fs=new FileStream (filename,System.IO.FileMode.Create);  
 30try 31    {  
 32     　request=(HttpWebRequest)HttpWebRequest.Create (strUrl);  
 33//接收的起始位置及接收的长度   34    　request.AddRange(formm.filestartw [threadh],  
 35     　formm.filestartw [threadh]+formm.filesizew [threadh]);  
 36     　ns=request.GetResponse ().GetResponseStream ();//获得接收流   37     　nreadsize=ns.Read (nbytes,0,512);  
 38while (nreadsize>0)  
 39    　{  
 40     fs.Write (nbytes,0,nreadsize);  
 41     nreadsize=ns.Read (nbytes,0,512);  
 42     formm.listBox1 .Items .Add ("线程"+threadh.ToString ()+"正在接收");  
 43    　}  
 44    　fs.Close();  
 45    　ns.Close ();  
 46    }  
 47catch (Exception er)  
 48    {  
 49    　MessageBox.Show (er.Message );  
 50    　fs.Close();  
 51    }  
 52     formm.listBox1 .Items.Add ("进程"+threadh.ToString ()+"接收完毕!");  
 53     formm.threadw[threadh]=true;  
 54    　}}
 55 56该类和Form1类处于统一命名空间，但不包含在Form1类中。下面定义“开始接收”按钮控件的事件响应函数：
 57 58privatevoid button1_Click(object sender, System.EventArgs e)  
 59    {  
 60     　DateTime dt=DateTime.Now;//开始接收时间   61     　textBox1.Text =dt.ToString ();  
 62     　strurl=textBox2.Text .Trim ().ToString ();  
 63    　HttpWebRequest request;  
 64long filesize=0;  
 65try 66    　{  
 67     request=(HttpWebRequest)HttpWebRequest.Create (strurl);  
 68     filesize=request.GetResponse ().ContentLength;//取得目标文件的长度   69    request.Abort ();  
 70    　}  
 71catch (Exception er)  
 72    　{  
 73    MessageBox.Show (er.Message );  
 74    　}  
 75// 接收线程数   76     　thread=Convert.ToInt32 (textBox4.Text .Trim().ToString (),10);  
 77//根据线程数初始化数组   78     　threadw=newbool [thread];  
 79     　filenamew=newstring [thread];  
 80     　filestartw=newint [thread];  
 81     　filesizew=newint[thread];  
 82 83//计算每个线程应该接收文件的大小   84int filethread=(int)filesize/thread;//平均分配   85int filethreade=filethread+(int)filesize%thread;//剩余部分由最后一个线程完成  
 86//为数组赋值   87for (int i=0;i<thread;i++)  
 88    　{  
 89     threadw[i]=false;//每个线程状态的初始值为假   90     filenamew[i]=i.ToString ()+".dat";//每个线程接收文件的临时文件名   91if (i<thread-1)  
 92    {  
 93     　filestartw[i]=filethread*i;//每个线程接收文件的起始点   94     　filesizew[i]=filethread-1;//每个线程接收文件的长度   95    }  
 96else 97    {  
 98     　filestartw[i]=filethread*i;  
 99     　filesizew[i]=filethreade-1;  
100    }  
101    　}  
102//定义线程数组，启动接收线程  103     　Thread[] threadk=new Thread [thread];  
104     　HttpFile[] httpfile=new HttpFile [thread];  
105for (int j=0;j<thread;j++)  
106    　{  
107     httpfile[j]=new HttpFile(this,j);  
108     threadk[j]=new Thread(new ThreadStart (httpfile[j].receive ));  
109    threadk[j].Start ();  
110    　}  
111//启动合并各线程接收的文件线程  112     　Thread hbth=new Thread (new ThreadStart (hbfile));  
113    　hbth.Start ();  
114     }

                public
                void
                 hbfile()  
    {  
    　
                while (true)//等待      　{  
    hb=true;  
    for (int i=0;i<thread;i++)  
    {  
    　if (threadw[i]==false)//有未结束线程，等待      　{  
    hb=false;  
    Thread.Sleep (100);  
    break;  
    　}  
    }  
    if (hb==true)//所有线程均已结束，停止等待，      {  
    　break;  
    }  
    　}  
    　FileStream fs;//开始合并      　FileStream fstemp;  
    　int readfile;  
    　byte[] bytes=newbyte[512];  
    　fs=new FileStream (textBox3.Text .Trim ().ToString (),System.IO.FileMode.Create);  
    　for (int k=0;k0)  
    　{  
    fs.Write (bytes,0,readfile);  
    　}  
    　else
    　{  
    break;  
    　}  
    }  
    fstemp.Close ();  
    　}  
    　fs.Close ();  
    　DateTime dt=DateTime.Now;  
    　textBox1.Text =dt.ToString ();//结束时间  
    　MessageBox.Show ("接收完毕!!!");  
    }