首先说一下ftp的特点是：传输速度快，适用于上传大文件，适用于局域网络。

直奔主题，这里采用apache提供的网络包，commons-net.jar。我用的3.3。

ftp上传需要ftp服务器。这里描述客户端的实现。

spring 文件上传这一块就不做描述

直接代码（上传）

@RequestMapping(value = "/uploadConfigFile")   @ResponseBody   public void uploadConfigFile(@RequestParam("uploadFile") MultipartFile uploadFile){    FTPClient ftpClient = new FTPClient();     try {      ftpClient.connect("120.120.120.156",21);      ftpClient.login("user1", "user1");      ftpClient.enterLocalPassiveMode();     ftpClient.setFileType(FTP.BINARY_FILE_TYPE);          //设置上传目录      ftpClient.changeWorkingDirectory("/GOS_CAS/RECONVERT/cas_config_reconvert");      String fileName = new String(uploadFile.getOriginalFilename().getBytes("utf-8"),"iso-8859-1");          FTPFile[] fs = ftpClient.listFiles();       if (fs!=null && fs.length>0) {      for(int i=0;i<fs.length;i++){       if (fs[i].getName().equals(fileName)) {        ftpClient.deleteFile(fs[i].getName());        break;       }      }     }     OutputStream os = ftpClient.appendFileStream(fileName);     byte[] bytes = new byte[1024];     InputStream is = uploadFile.getInputStream();     // 开始复制 其实net已经提供了上传的函数，但是我想可能是我这个版本有点问题                                                           //ftpClient.storeFile("", fis); 

                                            // 于是我自己write出去了，其实我想都是一样的效果，在这里告诉大家这两种方式都能实现 

                         int c;     // 暂未考虑中途终止的情况     while ((c = is.read(bytes)) != -1) {      os.write(bytes, 0, c);     }     os.flush();     is.close();     os.close();     RestoreConfiguration restoreConfiguration = new RestoreConfiguration();     restoreConfiguration.setStrName(fileName);     getServiceStub().restoreConfiguration(restoreConfiguration);    } catch (IOException e) {      e.printStackTrace();     } finally {      try {       ftpClient.disconnect();      } catch (IOException e) {       e.printStackTrace();      }     }   }

下载

@RequestMapping(value = "/downloadConfigFile")   public void downloadConfigFile(HttpServletResponse response,@RequestParam("fileName")String fileName) {        response.setCharacterEncoding("UTF-8");    response.setContentType("multipart/form-data");         FTPClient ftpClient = new FTPClient();         try {              int reply;              ftpClient.connect("120.120.120.156",21);                ftpClient.login("user1", "user1");            reply = ftpClient.getReplyCode();              if (!FTPReply.isPositiveCompletion(reply)) {               ftpClient.disconnect();                return;              }            ftpClient.changeWorkingDirectory("/GOS_CAS/BACKUP/cas_config_backup");//转移到FTP服务器目录              FTPFile[] fs = ftpClient.listFiles();              for(int i=0;i<fs.length;i++){                  if(fs[i].getName().equals(fileName)){                 String saveAsFileName = new String(fs[i].getName().getBytes("UTF-8"), "ISO8859-1");             response.setHeader("Content-Disposition", "attachment;fileName="+saveAsFileName);           OutputStream os = response.getOutputStream();                    ftpClient.retrieveFile(fs[i].getName(), os);                    os.flush();                    os.close();                    break;                }            }            ftpClient.logout();          } catch (IOException e) {              e.printStackTrace();          } finally {              if (ftpClient.isConnected()) {                  try {                      ftpClient.disconnect();                  } catch (IOException ioe) {                  }              }          }     }