java如何使用ftp下载远程服务器文件

    public Result<?> download(){
		//进行下载文件---------------------------------开始
        //远程服务器下载地址
        String fileurl = "ftp://superAdmin:superAdmin123@192.168.1.8:8888/usr/mp4pt/rec/CHN0/10110120011100/00001.mp4";
        //文件物理路径
        String realfilepath = "F:/rhsftdemo/00001.mp4";
        //本地中新建文件夹目录
        File file = new File("F:/rhsftdemo/");
        if (!file.exists()) {
            file.mkdirs();
        }
        log.info("存储路径realfilepath:" + realfilepath + "下载路径：" + fileurl);
        download(fileurl,realfilepath);
        return Result.ok();
    }

    private static final int BUFFER_SIZE = 4096;
    public void download(String ftpUrl,String savePath){
        long startTime = System.currentTimeMillis();
//        String ftpUrl = "ftp://ftp.f-secure.com/misc/unixutil/skeysrcs.zip";
        String file = "";
        // name of the file which has to be download
        String host = ""; // ftp server
        String user = ""; // user name of the ftp server
        String pass = ""; // password of the ftp server
//        String savePath = "F:\\skeysrcs.zip";
        ftpUrl = String.format(ftpUrl, user, pass, host);
        System.out.println("Connecting to FTP server");
        try {
            URL url = new URL(ftpUrl);
            URLConnection conn = url.openConnection();
            InputStream inputStream = conn.getInputStream();
            long filesize = conn.getContentLength();
            System.out.println("Size of the file to download in kb is:-" + filesize / 1024);
            FileOutputStream outputStream = new FileOutputStream(savePath);
            byte[] buffer = new byte[BUFFER_SIZE];
            int bytesRead = -1;
            while ((bytesRead = inputStream.read(buffer)) != -1) {
                outputStream.write(buffer, 0, bytesRead);
            }
            long endTime = System.currentTimeMillis();
            System.out.println("File downloaded");
            System.out.println("Download time in sec. is:-" + (endTime - startTime) / 1000);
            outputStream.close();
            inputStream.close();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }

   public Result<?> download(){
        //进行下载文件---------------------------------开始
        //远程服务器下载地址
        String fileurl = "ftp://192.168.1.8:8888/usr/mp4pt/rec/CHN0/20220420095100/00001.mp4";
        //本地文件物理路径
        String realfilepath = "F:/rhsftdemo/00001.mp4";
        //本地中新建文件夹目录
        File file = new File("F:/rhsftdemo/");
        if (!file.exists()) {
            file.mkdirs();
        }
        log.info("存储路径realfilepath:" + realfilepath + "下载路径：" + fileurl);
        boolean bb = retepasvfile(realfilepath,fileurl,"00001.mp4");
        return Result.ok();
    }


/**
     * 本地保存
     *
     * @param localurl 本地文件物理路径
     * @param hosturl 远程服务器下载地址
     * @param filename 文件名称
     *
     * @return
     */
    public synchronized boolean retepasvfile(String localurl, String hosturl, String filename) {
        FTPClient ftp = new FTPClient();
        boolean re = false;
        try {
            log.info("本地存储路径==:" + localurl);
            File file = FileUtil.getFile(localurl);
            ftp.setConnectTimeout(10000);
            ftp.setDataTimeout(10000);
            ftp.connect("192.168.1.8", 21);
            if (!org.springframework.util.StringUtils.isEmpty("admin") && !org.springframework.util.StringUtils.isEmpty("superAdmin123") && "superAdmin" != "null" && "superAdmin123" != "null") {
                //这里输入账号密码
                ftp.login("superAdmin", "superAdmin123");
            } else {
                log.info("开始链接ftp:");
                ftp.login("anonymous", "anonymous");
            }

            //ftp.bin();
            //  String str=ftp.pwd();
            ftp.enterLocalPassiveMode(); //被动模式
            ftp.setControlKeepAliveTimeout(60);
            ftp.setFileType(FTP.BINARY_FILE_TYPE);
            boolean b = ftp.changeWorkingDirectory(hosturl.substring(0, hosturl.lastIndexOf("/")));
            log.info("pwd：" + b + "---切换目录：" + hosturl.substring(0, hosturl.lastIndexOf("/")));
            long locationsize = file.length();//服务器上文件的大小
            if (b) {
                boolean res = false;
                res = ftp.retrieveFile(filename, new FileOutputStream(file));
                if (res) {
                    //ftp.disconnect();
                    log.info("文件下载完成");
                    re = true;
                } else {
                    log.info("文件下载失败");
                    //ftp.disconnect();
                }
            }
        } catch (Exception e) {
            e.getStackTrace();

            log.error("retepasvfileSamba:e=3" + e);
        } finally {
            try {
                ftp.disconnect();
            } catch (Exception e) {
            }
        }
        return re;
    }