title: 图片上传之FTP服务器
tags: Spring,Spring FTP,commons-net

前言

图片上传之Spring MVC 后台实现

通常图片、音频、视频都会占用大量的存储空间，我们在做后台开发的时候，会将这些文件存储到单独的FTP服务器，这样可以方便管理，并且很好的分离开业务。前面讲过图片上传的服务器的代码，这里将图片不保存到本地服务器，而是上传到FTP服务器。

Spring项目，添加FTP支持

Apache下面有个开源项目 commons-net，这个项目主要封装了各种网络协议的功能包括：FTP,SMTP,POP3,TELNET,ECHO等。

添加maven支持

<dependency>
    <groupId>commons-net</groupId>
    <artifactId>commons-net</artifactId>
    <version>3.5</version>
</dependency>

properties配置

ftp.host=com.xxx.ftp
ftp.port=21
ftp.username=ftpusername
ftp.password=ftppassword
ftp.savePath=ftppath/
ftp.downloadUrl=http://xxxxx/ftppath/

上述为ftp服务器的地址、端口、用户名、文件保存路径、文件访问路径等信息，将这些信息放入props-ftp.properties，然后放入spring 的配置place-holder中

<context:property-placeholder location="classpath*:conf/props-*.properties"/>

将properties映射到model

@Component
public class FtpConfig {
    @Value("${ftp.host}")
    private String host;
    @Value("${ftp.port}")
    private int port;
    @Value("${ftp.username}")
    private String username;
    @Value("${ftp.password}")
    private String password;
    @Value("${ftp.savePath}")
    private String savePath;
    @Value("${ftp.downloadUrl}")
    private String downloadUrl;

    public String getDownloadUrl() {
        return downloadUrl;
    }

    public void setDownloadUrl(String downloadUrl) {
        this.downloadUrl = downloadUrl;
    }

    public int getPort() {
        return port;
    }

    public void setPort(int port) {
        this.port = port;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getSavePath() {
        return savePath;
    }

    public void setSavePath(String savePath) {
        this.savePath = savePath;
    }

    public String getHost() {
        return host;
    }

    public void setHost(String host) {
        this.host = host;
    }
}

Controller代码

/**
 * Created by cody on 2016/12/26.
 * <p>
 * 附件上传、获取Controller
 */
@Controller
@RequestMapping(value = {"upload", "attachment"})
public class AttachmentController {
    private static final Logger logger = Logger.getLogger(AttachmentController.class);

    @Autowired
    private AttachmentService attachmentService;

    @RequestMapping(value = {"image", "file", "bin", "apk"}, method = RequestMethod.POST)
    @ResponseBody
    public Object uploadBinary(@RequestParam("file") MultipartFile file, HttpServletRequest request,
                               @Autowired ApiMessage apiMessage) {
        try {
            attachmentService.saveToFtp(file, apiMessage);
        } catch (Exception e) {
            logger.debug(e);
        }
        return apiMessage;
    }
}

Service 代码

/**
 * Created by cody on 2016/12/27.
 *
 * 附件、图片、logo service
 *
 */
@Service
public class AttachmentService {

    private static final Logger logger = Logger.getLogger(AttachmentService.class);

    @Autowired
    private FtpConfig ftpConfig;

    @Autowired
    private AttachmentDao attachmentDao;

    /**
     * 保存文件到ftp
     * @param file
     * @param apiMessage
     */
    public void saveToFtp(MultipartFile file, ApiMessage apiMessage) {
        //无上传的文件
        if(file == null || file.isEmpty()){
            apiMessage.setSuccess(false);
            apiMessage.setStatusCode(ERROR_NO_FILE);
            apiMessage.setMessage("未发现文件");
            return;
        }

        //获取文件名
        String originalName = file.getOriginalFilename();
        String ext = originalName.substring(originalName.lastIndexOf('.'));
        String outFileName = UUID.randomUUID() + ext;

        FTPClient ftp = new FTPClient();
        try{
            ftp.connect(ftpConfig.getHost(),ftpConfig.getPort());
            boolean loginSuccess = ftp.login(ftpConfig.getUsername(),ftpConfig.getPassword());
            if(loginSuccess){//登录成功

                int reply = ftp.getReplyCode();
                if(FTPReply.isPositiveCompletion(reply)){
                    ftp.setFileType(FTPClient.BINARY_FILE_TYPE);
                    ftp.setRemoteVerificationEnabled(false);
                    //切换到目标目录
//                    String dir = ftp.printWorkingDirectory();
                    ftp.changeWorkingDirectory(ftpConfig.getSavePath());
                    //上传文件
                    boolean success = ftp.storeFile(outFileName,file.getInputStream());
                    if(!success){
                        apiMessage.setSuccess(false);
                        apiMessage.setMessage("上传到ftp失败");
                        return;
                    }
                    String url = ftpConfig.getDownloadUrl() + outFileName;
                    TAttachment attachment = new TAttachment();
                    attachment.setUrl(url);
                    //将URL保存到Attachment数据库,并返回
                    attachmentDao.add(attachment);
                    apiMessage.setResult(attachment);
                }else{//没有应答
                    apiMessage.setSuccess(false);
                    apiMessage.setStatusCode(ERROR_FTP_NO_REPLY);
                }
            }else{//登录失败
                logger.error("ftp登录失败");
                apiMessage.setSuccess(false);
                apiMessage.setStatusCode(ERROR_FTP_LOGIN_ERROR);
            }
        }catch (Exception e){
            logger.error(e);
            apiMessage.setSuccess(false);
            apiMessage.setStatusCode(ERROR_UPLOAD_EXCEPTION);
        }finally {
            try {
                ftp.logout();
                ftp.disconnect();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
}