private static final int CR = (int)'\r';
private static final int LF = (int)'\n';

public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException
  {String fileName=null;

//Поток, в который будет писаться содержимое 
    int[] dataSlice = extractData(request);
  
   response.setContentType("text/html;charset=Cp1251");
   try { FileOutputStream fos = new FileOutputStream("/tmp/file.txt");
    int i;
    for(i=0; i<dataSlice.length; i++)     
       fos.write(dataSlice[i]);
     fos.flush();
    fos.close();
    fileName=newFile("/tmp/file.txt",response);
    download(fileName, response);
    }
   catch (IOException e)
   {
	   System.out.println(e.getMessage());
   }
  }

  private String newFile(String fileName,HttpServletResponse response) throws IOException
  { 
	  String stroka=null;
	  String nFileName=null;
	  resp.setContentType("text/html;charset=Cp1251");
	
	  try{
			
		
		  
		
			FileInputStream fis = fis=new FileInputStream(fileName);
			BufferedInputStream bis = new BufferedInputStream(fis);
			  DataInputStream BRf = new DataInputStream(bis);
			
	    
		    stroka=BRf.readLine();//читается пустая строка
		 
		    stroka=BRf.readLine();//мусор
		 
		    stroka=BRf.readLine();// инфа о файле в том числе имя файла
		    
		    String str[]=stroka.split(" ");
	     
		    int num=10;  		    
		    
		    nFileName=str[str.length-1].substring(num,str[str.length-1].length()-1);// получаем имя файла
		 	 
		    BufferedWriter out = new BufferedWriter(
		            new FileWriter("/tmp/"+nFileName));
		   
		    
		    stroka=BRf.readLine();
		    do{
		        
		    	stroka=BRf.readLine();
		    	if (stroka!=null)
		    	out.write(stroka);
		    	
		        		    }while(stroka!=null);
		    out.close();
		    fis.close();
                          bis.close();
		    BRf.close();
	  }
		    
	  catch (IOException e) 
	  {
		  System.out.println(e.getMessage());
		
	  }
	 
	 
	  return ("/tmp/"+nFileName);
	  
  }
  protected void processRequest(HttpServletRequest request, HttpServletResponse response)
  throws ServletException, IOException {
      response.setContentType("text/html;charset=Cp1251");
     
}
  
  private int[] extractData(HttpServletRequest request) throws IOException
    {
// Содержимое пришедших байтов их запроса (содержимое приходящего файла)
    InputStream is = request.getInputStream();
    int[] data = new int[request.getContentLength()];
    int bytes;
    int counter = 0;
    while((bytes=is.read())!=-1)
      {
      data[counter]=bytes;
      counter++;
      }
    is.close();

// Определение индексов срезки
    int i;
    int beginSliceIndex = 0;
// Конечный индекс срезки - длина границы + доп. символы.
    int endSliceIndex = data.length - getBoundary(request).length()-9;

    for(i = 0; i < data.length; i++)
      {
// Начальный индекс срезки: после того как встретятся 2 раза подряд \r\n
      if(data[i] == CR && data[i+1] == LF && data[i+2] == CR && data[i+3] == LF)
        {
        beginSliceIndex = i+4;
        break;
      }
    }

  int[] dataSlice = new int[endSliceIndex-beginSliceIndex+1];
  for(i = beginSliceIndex; i<=endSliceIndex; i++)
    {
    dataSlice[i-beginSliceIndex]=data[i];
    }

  return dataSlice;
  }

// Поиск границы
private String getBoundary(HttpServletRequest request)
  {
  String cType = request.getContentType();
  return cType.substring(cType.indexOf("boundary=")+9);
  }

private void download(String filename, HttpServletResponse response){
    try {
          File file = new File(filename);

          response.setContentType("text/html;charset=Cp1251;application/octet-stream");
          response.setHeader("Content-Disposition", "attachment; filename=\""+filename+"\"");

          ServletOutputStream sos = response.getOutputStream();
          DataInputStream dis = new DataInputStream(new FileInputStream(file));

          beginTransfer(dis, sos);

    } catch (Exception ex) {
          System.out.println(ex.getMessage());
    }
}

private void beginTransfer(DataInputStream dis,ServletOutputStream sos) throws IOException{
    byte[] buffer = new byte[1];
    while (dis.read(buffer) != -1) 
    {
            
    	sos.write(buffer);
    }
    dis.close();
    sos.close();
}

 <form action="UploadServlet" method="post" enctype="multipart/form-data">
                <input name="data" type="file"><br>
                <input type="submit"><br>
  </form>

  FileInputStream fis = new FileInputStream(new File(fileName));
		  BufferedReader BRf = new BufferedReader(new InputStreamReader(fis,
		  "Cp1251"));

BufferedReader BRf = new BufferedReader(new InputStreamReader(fis,"Cp1251"));