springboot集成ftp

springboot集成ftp

pom依赖包

<dependency>
     <groupId>commons-net</groupId>
      <artifactId>commons-net</artifactId>
      <version>3.6</version>
</dependency>

ftp登录初始化

 private FTPClient connectFtpServer(){
        FTPClient ftpClient = new FTPClient();
        ftpClient.setConnectTimeout(1000*30);//设置连接超时时间
        ftpClient.setControlEncoding("utf-8");//设置ftp字符集
        ftpClient.enterLocalPassiveMode();//设置被动模式，文件传输端口设置
        try {
            ftpClient.setFileType(FTP.BINARY_FILE_TYPE);//设置文件传输模式为二进制，可以保证传输的内容不会被改变
            ftpClient.connect(url);
            ftpClient.login(userName,password);
            int replyCode = ftpClient.getReplyCode();
            if (!FTPReply.isPositiveCompletion(replyCode)){
                LOGGER.error("connect ftp {} failed",url);
                ftpClient.disconnect();
                return null;
            }
            LOGGER.info("replyCode==========={}",replyCode);
        } catch (IOException e) {
            LOGGER.error("connect fail ------->>>{}",e.getCause());
            return null;
        }
        return ftpClient;
}

ftp上传文件

 /**
     *
     * @param inputStream 待上传文件的输入流
     * @param originName 文件保存时的名字
     */
    public void uploadFile(InputStream inputStream, String originName){
        FTPClient ftpClient = connectFtpServer();
        if (ftpClient == null){
            return;
        }

        try {
            ftpClient.changeWorkingDirectory(remoteDir);//进入到文件保存的目录
            Boolean isSuccess = ftpClient.storeFile(originName,inputStream);//保存文件
            if (!isSuccess){
                throw new BusinessException(ResponseCode.UPLOAD_FILE_FAIL_CODE,originName+"---》上传失败！");
            }
            LOGGER.info("{}---》上传成功！",originName);
            ftpClient.logout();
        } catch (IOException e) {
            LOGGER.error("{}---》上传失败！",originName);
            throw new BusinessException(ResponseCode.UPLOAD_FILE_FAIL_CODE,originName+"上传失败！");
        }finally {
            if (ftpClient.isConnected()){
                try {
                    ftpClient.disconnect();
                } catch (IOException e) {
                    LOGGER.error("disconnect fail ------->>>{}",e.getCause());
                }
            }
        }
    }

ftp读取文件，并转成base64

/**
     *  读ftp上的文件，并将其转换成base64
     * @param remoteFileName ftp服务器上的文件名
     * @return
     */
 public String readFileToBase64(String remoteFileName){
        FTPClient ftpClient = connectFtpServer();
        if (ftpClient == null){
            return null;
        }

        String base64 = "";
        InputStream inputStream = null;

        try {
            ftpClient.changeWorkingDirectory(remoteDir);
            FTPFile[] ftpFiles = ftpClient.listFiles(remoteDir);
            Boolean flag = false;
            //遍历当前目录下的文件，判断要读取的文件是否在当前目录下
            for (FTPFile ftpFile:ftpFiles){
                if (ftpFile.getName().equals(remoteFileName)){
                    flag = true;
                }
            }

            if (!flag){
                LOGGER.error("directory：{}下没有 {}",remoteDir,remoteFileName);
                return null;
            }
            //获取待读文件输入流
            inputStream = ftpClient.retrieveFileStream(remoteDir+remoteFileName);

            //inputStream.available() 获取返回在不阻塞的情况下能读取的字节数，正常情况是文件的大小
            byte[] bytes = new byte[inputStream.available()];

            inputStream.read(bytes);//将文件数据读到字节数组中
            BASE64Encoder base64Encoder = new BASE64Encoder();
            base64 = base64Encoder.encode(bytes);//将字节数组转成base64字符串
            LOGGER.info("read file {} success",remoteFileName);
            ftpClient.logout();
        } catch (IOException e) {
            LOGGER.error("read file fail ----->>>{}",e.getCause());
            return null;
        }finally {
            if (ftpClient.isConnected()){
                try {
                    ftpClient.disconnect();
                } catch (IOException e) {
                    LOGGER.error("disconnect fail ------->>>{}",e.getCause());
                }
            }

            if (inputStream != null){
                try {
                    inputStream.close();
                } catch (IOException e) {
                    LOGGER.error("inputStream close fail -------- {}",e.getCause());
                }
            }

        }

        return base64;

 }

ftp下载文件

    /**
     * 文件下载
     * @param remoteFileName ftp上的文件名
     * @param localFileName 本地文件名
     */
public void download(String remoteFileName,String localFileName){
        FTPClient ftpClient = connectFtpServer();
        if (ftpClient == null){
            return ;
        }

        OutputStream outputStream = null;

        try {
            ftpClient.changeWorkingDirectory(remoteDir);
            FTPFile[] ftpFiles = ftpClient.listFiles(remoteDir);
            Boolean flag = false;
            //遍历当前目录下的文件，判断是否存在待下载的文件
            for (FTPFile ftpFile:ftpFiles){
                if (ftpFile.getName().equals(remoteFileName)){
                    flag = true;
                    break;
                }
            }

            if (!flag){
                LOGGER.error("directory：{}下没有 {}",remoteDir,remoteFileName);
                return ;
            }

            outputStream = new FileOutputStream(localDir+localFileName);//创建文件输出流

            Boolean isSuccess = ftpClient.retrieveFile(remoteFileName,outputStream); //下载文件
            if (!isSuccess){
                LOGGER.error("download file 【{}】 fail",remoteFileName);
            }

            LOGGER.info("download file success");
            ftpClient.logout();
        } catch (IOException e) {
            LOGGER.error("download file 【{}】 fail ------->>>{}",remoteFileName,e.getCause());
        }finally {
            if (ftpClient.isConnected()){
                try {
                    ftpClient.disconnect();
                } catch (IOException e) {
                    LOGGER.error("disconnect fail ------->>>{}",e.getCause());
                }
            }

            if (outputStream != null){
                try {
                    outputStream.close();
                } catch (IOException e) {
                    LOGGER.error("outputStream close fail ------->>>{}",e.getCause());
                }
            }
        }
    }

ftp客户端与服务端之间数据传输，主动模式和被动模式

请移至这个哥们的博文中查看，https://www.cnblogs.com/mawanglin2008/articles/3607767.html，写的非常好。

主动模式：ftp客户端产生一个随机端口，并告知ftp服务端，最后服务端的20端口会与这个随机端口建立连接，进行数据传输

被动模式：ftp服务端产生一个随机端口，并告知ftp客户端，最后客户端与这个随机端口建立连接，进行数据传输