一个下载线程

Thread run=new Thread(){
		 
		@Override
		public void run() {
			InputStream is = null;   
			OutputStream fos = null;
			File file = new File(savePath);
			if(!file.exists()){   
				file.mkdirs();   
			}  
			try {   
				URL url = new URL(myurl);   
				URLConnection urlConn = url.openConnection(); 
				is = urlConn.getInputStream();   
				int length = urlConn.getContentLength();   //文件大小   
				File oldFile = new File(savePath+fileName);
				if(oldFile.exists())
				{
					oldFile.delete();
				}
				fos = openFileOutput(fileName,Context.MODE_WORLD_READABLE);
							              
				int count = 0,numread = 0;   
				byte buf[] = new byte[1024];   
				while((numread = is.read(buf))!=-1){   
					count+=numread;   
					int progressCount =(int)(((float)count / length) * 100);
					changeProgress(progressCount);
					fos.write(buf, 0, numread);   
				}   
				fos.flush();  
				Message msg1 = newhandler.obtainMessage(1);
				newhandler.sendMessage(msg1);
			} catch (Exception e) {  
				e.printStackTrace();     
			}finally{   
				try {   
					if(fos!=null){
						fos.close();   
					}   
					if(is!=null)  {
						is.close();   
					} 
				} catch (IOException e) {
				e.printStackTrace();   
				}   
			}
		}
    };