android连接服务器下载文件工具类详解编程语言

    public static File downLoad(String serverPath,String savedPath,ProgressDialog dialog){   
            try {   
                   
                URL url=new URL(serverPath);   
                HttpURLConnection _conn=(HttpURLConnection) url.openConnection();   
                _conn.setRequestMethod("GET");   
                _conn.setConnectTimeout(5000);   
                int code=_conn.getResponseCode();   
                if(code==200){   
                    //设置进度条的长度   
                    dialog.setMax(_conn.getContentLength());   
                    InputStream is=_conn.getInputStream();   
                    File _file=new File(savedPath);   
                    FileOutputStream _FileOutputStream=new FileOutputStream(_file);   
                    int len=0;   
                    byte[] buffer= new byte[1024];   
                    int _total=0;   
                    while((len=is.read(buffer))!=-1){   
                        _FileOutputStream.write(buffer, 0,len);   
                        _total+=len;   
                        dialog.setProgress(_total);   
                        Thread.sleep(20);   
                    }   
                    _FileOutputStream.flush();   
                    _FileOutputStream.close();   
                    is.close();   
                    return _file;   
                }else {   
                    return null;   
                }   
            } catch (Exception e) {   
                // TODO Auto-generated catch block   
                e.printStackTrace();   
                return null;   
            }   
               
               
        }