java访问ftp

1、连接ftp

       FTPClient ftpClient = new FTPClient();
        ftpClient.connect(host,port);
        ftpClient.login(userName, password);
        ftpClient.setControlEncoding(encoding);
        ftpClient.changeWorkingDirectory(workDir);
        ftpClient.setFileType(FTP.BINARY_FILE_TYPE);//设置上传文件类型为二进制，否则将无法打开文件
        ftpClient.enterLocalPassiveMode();
        

2、从ftp下载文件

        String base64;
        InputStream inputStream = null;

        try {
　　　　　　　　///防止中文乱码
            if (!StringUtils.isEmpty(remotDir)){
                remoteFileName = new  String(remotDir.getBytes("GBK"), "iso-8859-1")+
                        File.separator+new  String(remoteFileName.getBytes("GBK"), "iso-8859-1");
            }else{
                remoteFileName = new  String(remoteFileName.getBytes("GBK"), "iso-8859-1");
            }
            //获取待读文件输入流
            inputStream = ftpClient.retrieveFileStream(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
            Base64.Encoder encoder = Base64.getEncoder();
            base64 = encoder.encodeToString(bytes);//将字节数组转成base64字符串
            log.info("read file {} success",remoteFileName);
//            ftpClient.logout();
        } catch (IOException e) {
            log.error("read file fail ----->>>{}",e.getCause());
            return null;
        }finally {
            if (null!=inputStream){
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

3、向ftp上传文件

 try {
            if (!StringUtils.isEmpty(remoteDir)){
                originName = new String(remoteDir.getBytes("GBK"),"iso-8859-1")+File.separator+
                        new String(originName.getBytes("GBK"),"iso-8859-1");
            }else{
                originName =  new String(originName.getBytes("GBK"),"iso-8859-1");
            }
            Boolean isSuccess = ftpClient.storeFile(originName,inputStream);//保存文件
            if (!isSuccess){
                throw new FtpException(originName+"---》上传失败！");
            }
            log.info("{}---》上传成功！",originName);
        } catch (IOException e) {
            log.error("{}---》上传失败！",originName);
            throw new FtpException(originName+"上传失败！");
        }finally {
            if (null!=inputStream){
                try {
                    inputStream.close();
                } catch (IOException e) {
                    log.debug(e.getMessage());
                }
            }
           
        }