if(fclient.isConnected()){
                //设置文件传输类型为二进制
                fclient.setFileType(FTPClient.BINARY_FILE_TYPE);
                int reply=fclient.getReplyCode();
                if(!FTPReply.isPositiveCompletion(reply)){
                    fclient.disconnect();
                    System.err.println("FTP sever refused connectd");
                    System.exit(-1);
                }    
                   }