package download;import javax.swing.UIManager;import java.awt.*;import java.io.DataOutputStream;import java.net.HttpURLConnection;import java.io.IOException;import java.io.FileInputStream;import java.net.URL;import java.io.File;import java.io.DataInputStream;import java.io.FileOutputStream;import java.io.InputStream;import java.io.Serializable;import java.io.RandomAccessFile;//Java實現網絡文件傳輸,在客戶端請求Web服務器傳輸指定文件，并將文件保存。public class HttpDownload {  private String sWebAddr = "http://kent.dl.sourceforge.net/sourceforge/jamper/Sample.zip"; // 定義Web地址和文件名  // 例如，傳輸http://cs.bnu.edu.cn/source/vb/地址的vb.zip 則 sWebAddr = "http://cs.bnu.edu.cn/source/vb/vb.zip"  private String sSavePath = "d:\\temp";            // 定義存文件路徑  private String sSaveName = "sample.zip";         // 定義文件名  public HttpDownload(){    try{      CacthInfo bean = new CacthInfo(sWebAddr,sSavePath,sSaveName,5);      CacthFile fileFetch = new CacthFile(bean);      fileFetch.start();    }    catch(Exception e){      e.printStackTrace ();    }  }  public static void main(String[] args){    new HttpDownload();  }}class CacthFile extends Thread {   // 傳輸文件線程類  CacthInfo siteInfoBean = null; //文件信息Bean  long[] nPos;  long[] nStartPos; //開始位置  long[] nEndPos; //結束位置  PartCacth[] fileSplitterFetch; //子線程對象  long nFileLength; //文件長度  boolean bFirst = true; //是否第一次取文件  boolean bStop = false; //停止標志  File tmpFile; //文件傳輸臨時信息  DataOutputStream output; //輸出到文件的輸出流  public CacthFile(CacthInfo bean) throws IOException{    siteInfoBean = bean;    tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");    if(tmpFile.exists ()){      bFirst = false;      read_nPos();    }    else{      nStartPos = new long[bean.getNSplitter()];      nEndPos = new long[bean.getNSplitter()];    }  }  public void run(){    //獲得文件長度    //分割文件    //實例PartCacth    //啟動PartCacth線程    //等待子線程返回    try{      if(bFirst){        nFileLength = getFileSize();        if(nFileLength == -1){          System.err.println("File Length is not known!");        }        else          if(nFileLength == -2){            System.err.println("File is not access!");          }          else{            for(int i=0;i<nStartPos.length;i++){              nStartPos[i] = (long)(i*(nFileLength/nStartPos.length));            }            for(int i=0;i<nEndPos.length-1;i++){              nEndPos[i] = nStartPos[i+1];            }            nEndPos[nEndPos.length-1] = nFileLength;          }      }      //啟動子線程      fileSplitterFetch = new PartCacth[nStartPos.length];      for(int i=0;i<nStartPos.length;i++){        fileSplitterFetch[i] = new PartCacth(siteInfoBean.getSSiteURL(),        siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),        nStartPos[i],nEndPos[i],i);        Addtion.log("Thread " + i + " , nStartPos = " + nStartPos[i] + ", nEndPos = " + nEndPos[i]);        fileSplitterFetch[i].start();      }      //等待子線程結束      //int count = 0;      //是否結束while循環      boolean breakWhile = false;      while(!bStop){        write_nPos();        Addtion.sleep(500);        breakWhile = true;        for(int i=0;i<nStartPos.length;i++){          if(!fileSplitterFetch[i].bDownOver){          breakWhile = false;          break;        }      }      if(breakWhile)        break;      }      System.out.println("文件傳輸結束！");    }    catch(Exception e){      e.printStackTrace ();    }  }  //獲得文件長度  public long getFileSize(){    int nFileLength = -1;    try{      URL url = new URL(siteInfoBean.getSSiteURL());      HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();      httpConnection.setRequestProperty("User-Agent","NetFox");      int responseCode=httpConnection.getResponseCode();      if(responseCode>=400){        processErrorCode(responseCode);        return -2; //-2 為Web服務器響應錯誤      }      String sHeader;      for(int i=1;;i++){        sHeader=httpConnection.getHeaderFieldKey(i);        if(sHeader!=null){          if(sHeader.equals("Content-Length")){            nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));            break;          }        }        else          break;      }    }    catch(IOException e){e.printStackTrace ();}    catch(Exception e){e.printStackTrace ();}    Addtion.log(nFileLength);    return nFileLength;  }  //保存傳輸信息（文件指針位置）  private void write_nPos(){    try{      output = new DataOutputStream(new FileOutputStream(tmpFile));      output.writeInt(nStartPos.length);      for(int i=0;i<nStartPos.length;i++){        // output.writeLong(nPos[i]);        output.writeLong(fileSplitterFetch[i].nStartPos);        output.writeLong(fileSplitterFetch[i].nEndPos);      }      output.close();    }    catch(IOException e){e.printStackTrace ();}    catch(Exception e){e.printStackTrace ();}  }  //讀取保存的下載信息（文件指針位置）  private void read_nPos(){    try{      DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));      int nCount = input.readInt();      nStartPos = new long[nCount];      nEndPos = new long[nCount];      for(int i=0;i<nStartPos.length;i++){        nStartPos[i] = input.readLong();        nEndPos[i] = input.readLong();      }      input.close();                //判斷每塊的文件開始位置是否大于結束位置            for(int i=0;i<nStartPos.length;i++){                if(nStartPos[i]>nEndPos[i]){                    nStartPos[i]=nEndPos[i];                }            }    }    catch(IOException e){e.printStackTrace ();}    catch(Exception e){e.printStackTrace ();}  }  private void processErrorCode(int nErrorCode){    System.err.println("Error Code : " + nErrorCode);  }  //停止文件傳輸  public void siteStop(){    bStop = true;    for(int i=0;i<nStartPos.length;i++)      fileSplitterFetch[i].splitterStop();  }}class CacthInfo {     // 定義獲取和設置相關文件信息類 private String sSiteURL;    // 定義URL變量 private String sFilePath; // 定義存文件路徑變量 private String sFileName; // 定義文件名變量 private int nSplitter; // 定義傳輸文件計數值 public CacthInfo(){   this("","","",5);     // 設置傳輸文件計數值 } public CacthInfo(String sURL,String sPath,String sName,int nSpiltter){   sSiteURL= sURL;   sFilePath = sPath;   sFileName = sName;   this.nSplitter = nSpiltter; } public String getSSiteURL(){   return sSiteURL; } public void setSSiteURL(String value){   sSiteURL = value; } public String getSFilePath(){   return sFilePath; } public void setSFilePath(String value){   sFilePath = value; } public String getSFileName(){   return sFileName; } public void setSFileName(String value){   sFileName = value; } public int getNSplitter(){   return nSplitter; } public void setNSplitter(int nCount){   nSplitter = nCount; }}class PartCacth extends Thread {  String sURL; // 定義文件傳輸時使用的變量  long nStartPos; // 分段文件傳輸開始位置  long nEndPos; // 分段文件傳輸結束位置  int nThreadID; // 子線程ID  boolean bDownOver = false; // 完成文件傳輸  boolean bStop = false; // 停止文件傳輸  StoreFile fileAccess = null;  public PartCacth(String sURL,String sName,long nStart,long nEnd,int id) throws IOException{    this.sURL = sURL;    this.nStartPos = nStart;    this.nEndPos = nEnd;    nThreadID = id;    fileAccess = new StoreFile(sName,nStartPos);  }  public void run(){    while(nStartPos < nEndPos && !bStop){      try{        URL url = new URL(sURL);        HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();        httpConnection.setRequestProperty("User-Agent","NetFox");        String sProperty = "bytes="+nStartPos+"-";        httpConnection.setRequestProperty("RANGE",sProperty);        Addtion.log(sProperty);        InputStream input = httpConnection.getInputStream();        byte[] b = new byte[1024];        int nRead;        while((nRead=iput.read(b,0,1024)) > 0 && nStartPos <nEndPos && !bStop){          nStartPos += fileAccess.write(b,0,nRead);        }        Addtion.log("Thread " + nThreadID + " is over!");        bDownOver = true;      }      catch(Exception e){        e.printStackTrace ();      }    }     bDownOver = true;  }  public void logResponseHead(HttpURLConnection con){    for(int i=1;;i++){      String header=con.getHeaderFieldKey(i);      if(header!=null)        Addtion.log(header+" : "+con.getHeaderField(header));      else        break;    }  }  public void splitterStop(){    bStop = true;  }}class StoreFile implements Serializable{    // 定義訪問文件類  RandomAccessFile oSavedFile;  long nPos;  public StoreFile() throws IOException{    this("",0);  }  public StoreFile(String sName,long nPos) throws IOException{    oSavedFile = new RandomAccessFile(sName,"rw");    this.nPos = nPos;    oSavedFile.seek(nPos);  }  public synchronized int write(byte[] b,int nStart,int nLen){    int n = -1;    try{      oSavedFile.write(b,nStart,nLen);      n = nLen;    }    catch(IOException e){      e.printStackTrace ();    }    return n;  }}