本文主要是介绍java实现从ftp服务器拷贝文件到另一台服务器，对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！

目录

• 前言
• • 1、连接ftp
  • 2、连接sftp
  • 3、获取ftp文件流
  • 4、在sftp连接服务器上创建目录
  • 5、上传到sftp所在服务器

前言

通过ftp连接ftp服务器，通过sftp连接另外一台服务器，实现文件拷贝。

1、连接ftp

/**
     * 连接FTP
     */
    public void connect(String host, int port, String user, String pwd) {
        FTPClient client = new FTPClient();
        try {
            // 连接
            client.connect(host, port);
            // 登陆
            if (user == null || "".equals(user)) {
                client.login("anonymous", "anonymous");
            } else {
                client.login(user, pwd);
            }
            // 二进制文件支持
            client.setFileType(FTPClient.BINARY_FILE_TYPE);
            // 获取FTP应答
            int reply = client.getReplyCode();
            if (!FTPReply.isPositiveCompletion(reply)) {
                client.disconnect();
                return;
            }
            FTPClientConfig config = new FTPClientConfig(client.getSystemType().split(" ")[0]);
            client.configure(config);
            client.setBufferSize(1024);
            client.enterLocalPassiveMode();
            client.setControlEncoding("utf-8");
            this.client = client;
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

2、连接sftp

/**
     * 连接sftp服务器
     *
     * @param host     主机
     * @param port     端口
     * @param username 用户名
     * @param password 密码
     */
    public void sessionConnect(String host, int port, String username, String password) {
        try {
            this.jsch = new JSch();
            this.sshSession = jsch.getSession(username, host, port);
            this.sshSession.setPassword(password);
            Properties sshConfig = new Properties();
            sshConfig.put("StrictHostKeyChecking", "no");
            this.sshSession.setConfig(sshConfig);
            this.sshSession.connect();
        } catch (Exception e) {
            log.error("SftpUtil Session host=[" + host + "];port=[" + port + "];user=[" + username
                    + "];passwd=[" + password + "] error : ", e);
        }
    }


    /**
     * 连接sftp
     */
    public SftpUtils sftpConnect() {
        if (sftp == null) {
            try {
                Channel channelSftp = this.sshSession.openChannel("sftp");
                this.sftp = (ChannelSftp) channelSftp;
                sftp.connect();
            } catch (Exception e) {
                log.error("SftpUtil ChannelSftp error : ", e.getMessage());
            }
        }
        return this;
    }

3、获取ftp文件流

 /**
     * 获取远程文件的输出流
     *
     * @param client     ftp连接，这里传进来是因为不能在该方法的最后释放连接
     * @param fileName   文件名称，FTP上的文件名称
     * @param remotePath ftp上的远程目录文件
     */
    public static InputStream retrieveFileStream(FTPClient client, String fileName, String remotePath) throws Exception {
        boolean success = false;

        try {
            success = switchDirectory(client, remotePath, false);
            if (success) {
                return client.retrieveFileStream(fileName);
            }
        } catch (Exception e) {
            log.debug("获取ftp文件流异常，error: {}", e.getMessage());
            throw new RuntimeException("获取ftp文件流异常 error" + e.getMessage());
        }
        return null;
    }

4、在sftp连接服务器上创建目录

		String mkdir = "mkdir -p " + remotePath;
        String exit = "exit";
        sftp.shellConnect().executeShell(mkdir, exit);

 /**
     * 创建shell连接
     */
    public SftpUtil shellConnect() {
        if (shell == null) {
            try {
                Channel chnanelShell = this.sshSession.openChannel("shell");
                shell = (ChannelShell) chnanelShell;
                shell.connect();
            } catch (Exception e) {
                log.error("SftpUtil ChannelShell error : ", e.getMessage());
            }
        }
        return this;
    }

/**
     * 执行shell 命令
     */
    public boolean executeShell(String... cmds) {
        ChannelShell shell = null;
        try {
            Channel chnanelShell = this.sshSession.openChannel("shell");
            shell = (ChannelShell) chnanelShell;
            shell.connect();
        } catch (JSchException e) {
            log.error("SftpUtil ChannelShell error : ", e);
        }
        try {
            InputStream in = shell.getInputStream();
            OutputStream out = shell.getOutputStream();
            PrintWriter writer = new PrintWriter(out);
            for (String cmd : cmds) {
                writer.println(cmd);
            }
            writer.flush();

            BufferedReader reader = new BufferedReader(new InputStreamReader(in));
            String msg = "";
            StringBuilder result = new StringBuilder();
            while ((msg = reader.readLine()) != null) {
//                result.append(msg).append(System.lineSeparator());
            }
        } catch (IOException e) {
            throw new RuntimeException("执行命令出错，cmd : " + ArrayUtils.toString(cmds) + " , error : " + e.getMessage());
        } finally {
            shell.disconnect();
        }

        return true;
    }

5、上传到sftp所在服务器

  /**
     * 上传文件
     *
     * @param src      要上传的文件流
     * @param dir      上传的目录
     * @param fileName 文件名称
     */
    public boolean uploadStream(InputStream src, String dir, String fileName) throws Exception {
        boolean success = false;
        try {
            this.sftp.cd(dir);
            this.sftp.put(src, fileName);
            success = true;
        } catch (Exception e) {
            log.error("SftpUtil upload directory=[" + dir + "];uploadFile=[" + fileName + "] error : ", e.getMessage());
            throw new RuntimeException("上传文件异常," + "upload directory=[" + dir + "];uploadFile=[" + fileName + "] error:" + e.getMessage());
        } finally {
            try {
                if (src != null) {
                    src.close();
                }
            } catch (IOException e) {
                log.error("SftpUtil upload directory=[" + dir + "];uploadFile=[" + fileName + "] close FileInputStream error : ", e);
            }
        }
        return success;
    }

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