java连接sftp服务器实现上传下载

矫情吗；* 2024-03-22 23:08 97阅读 0赞

### 前言 ###

我最初的需求是java读取远程windows服务器的文件。查了一圈，发现将远程服务器作为ftp服务器是最方便快捷的。着手准备，首先要让远程服务器提供ftp服务，再做相关配置，然后通过代码配置远程地址，用户名密码（ftp服务设置）读取文件。

### 一、给目标服务器安装sshd服务 ###

*  我目前使用的是 [freeSSHd.exe][]，下载后按照步骤一步步安装，最后俩弹窗，第一个选`是`，第二个选`否`。  
    ![创建私钥，选是][364a20b14fa246dcbc89ea8aca442758.png]  
    ![作为系统服务，选否][71b5fcb036b7459c920d2625dde2bf1f.png]

### 二、基础配置 ###

1.  双击打开安装好的程序，在右下角找到图标，右键，setting  
    ![加粗样式][70a5bd47e21d4b1b862e362493b8e2d0.png]
2.  按照步骤配置  
    ![在这里插入图片描述][ace798661b9542e5bb67a3e59a013667.png]  
    ![在这里插入图片描述][8fd7e4f381e84cf1bd6810e919eab98b.png]  
    ![在这里插入图片描述][6a5fd3ce66654e8b8f4de1a663e69f07.png]  
    ![在这里插入图片描述][3dc357601f1f48b4852300bb17ca600e.png]  
    ![在这里插入图片描述][bcbabac4426545a6a5736f1467c91262.png]
3.  unload之后重新打开，配置生效  
    ![在这里插入图片描述][bc9158c15531401283dc88081f572334.png]

### 三、java实现上传下载（main方法中有测试用例） ###

import java.io.ByteArrayInputStream;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.UnsupportedEncodingException;
    import java.util.*;
    
    import com.jcraft.jsch.*;
    import org.apache.commons.io.IOUtils;
    import org.apache.commons.lang3.StringUtils;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    
    /**
     *
     * @ClassName: SFTPUtil
     * @Description: sftp连接工具类
     * @version 1.0.0
     */
    public class SFTPUtil {
        
        private transient Logger log = LoggerFactory.getLogger(this.getClass());
    
        private ChannelSftp sftp;
    
        private Session session;
        /** FTP 登录用户名*/
        private String username;
        /** FTP 登录密码*/
        private String password;
        /** 私钥 */
        private String privateKey;
        /** FTP 服务器地址IP地址*/
        private String host;
        /** FTP 端口*/
        private int port;
    
    
        /**
         * 构造基于密码认证的sftp对象
         * @param username
         * @param password
         * @param host
         * @param port
         */
        public SFTPUtil(String username, String password, String host, int port) {
        
            this.username = username;
            this.password = password;
            this.host = host;
            this.port = port;
        }
    
        /**
         * 构造基于秘钥认证的sftp对象
         * @param username
         * @param host
         * @param port
         * @param privateKey
         */
        public SFTPUtil(String username, String host, int port, String privateKey) {
        
            this.username = username;
            this.host = host;
            this.port = port;
            this.privateKey = privateKey;
        }
    
        public SFTPUtil(){
        }
    
        /**
         * 连接sftp服务器
         *
         * @throws Exception
         */
        public void login(){
        
            try {
        
                JSch jsch = new JSch();
                if (privateKey != null) {
        
                    jsch.addIdentity(privateKey);// 设置私钥
                    log.info("sftp connect,path of private key file：{}" , privateKey);
                }
                log.info("sftp connect by host:{} username:{}",host,username);
    
                session = jsch.getSession(username, host, port);
                log.info("Session is build");
                if (password != null) {
        
                    session.setPassword(password);
                }
                Properties config = new Properties();
                config.put("StrictHostKeyChecking", "no");
    
                session.setConfig(config);
                session.connect();
                log.info("Session is connected");
    
                Channel channel = session.openChannel("sftp");
                channel.connect();
                log.info("channel is connected");
    
                sftp = (ChannelSftp) channel;
                log.info(String.format("sftp server host:[%s] port:[%s] is connect successfull", host, port));
            } catch (JSchException e) {
        
                log.error("Cannot connect to specified sftp server : {}:{} \n Exception message is: {}", new Object[]{
        host, port, e.getMessage()});
            }
        }
    
        /**
         * 关闭连接 server
         */
        public void logout(){
        
            if (sftp != null) {
        
                if (sftp.isConnected()) {
        
                    sftp.disconnect();
                    log.info("sftp is closed already");
                }
            }
            if (session != null) {
        
                if (session.isConnected()) {
        
                    session.disconnect();
                    log.info("sshSession is closed already");
                }
            }
        }
    
        /**
         * 将输入流的数据上传到sftp作为文件
         *
         * @param directory
         *            上传到该目录
         * @param sftpFileName
         *            sftp端文件名
         * @param input
         *            输入流
         * @throws SftpException
         * @throws Exception
         */
        public void upload(String directory, String sftpFileName, InputStream input) throws SftpException{
        
            try {
        
                sftp.cd(directory);
            } catch (SftpException e) {
        
                log.warn("directory is not exist");
                sftp.mkdir(directory);
                sftp.cd(directory);
            }
            sftp.put(input, sftpFileName);
            log.info("file:{} is upload successful" , sftpFileName);
        }
    
        /**
         * 上传单个文件
         *
         * @param directory
         *            上传到sftp目录
         * @param uploadFile
         *            要上传的文件,包括路径
         * @throws FileNotFoundException
         * @throws SftpException
         * @throws Exception
         */
        public void upload(String directory, String uploadFile) throws FileNotFoundException, SftpException{
        
            File file = new File(uploadFile);
            upload(directory, file.getName(), new FileInputStream(file));
        }
    
        /**
         * 将byte[]上传到sftp，作为文件。注意:从String生成byte[]是，要指定字符集。
         *
         * @param directory
         *            上传到sftp目录
         * @param sftpFileName
         *            文件在sftp端的命名
         * @param byteArr
         *            要上传的字节数组
         * @throws SftpException
         * @throws Exception
         */
        public void upload(String directory, String sftpFileName, byte[] byteArr) throws SftpException{
        
            upload(directory, sftpFileName, new ByteArrayInputStream(byteArr));
        }
    
        /**
         * 将字符串按照指定的字符编码上传到sftp
         *
         * @param directory
         *            上传到sftp目录
         * @param sftpFileName
         *            文件在sftp端的命名
         * @param dataStr
         *            待上传的数据
         * @param charsetName
         *            sftp上的文件，按该字符编码保存
         * @throws UnsupportedEncodingException
         * @throws SftpException
         * @throws Exception
         */
        public void upload(String directory, String sftpFileName, String dataStr, String charsetName) throws UnsupportedEncodingException, SftpException{
        
            upload(directory, sftpFileName, new ByteArrayInputStream(dataStr.getBytes(charsetName)));
        }
    
        /**
         * 下载文件
         *
         * @param directory
         *            下载目录
         * @param downloadFile
         *            下载的文件
         * @param saveFile
         *            存在本地的路径
         * @throws SftpException
         * @throws FileNotFoundException
         * @throws Exception
         */
        public void download(String directory, String downloadFile, String saveFile) throws SftpException, FileNotFoundException{
        
            if (directory != null && !"".equals(directory)) {
        
                sftp.cd(directory);
            }
            File file = new File(saveFile);
            sftp.get(downloadFile, new FileOutputStream(file));
            log.info("file:{} is download successful" , downloadFile);
        }
        /**
         * 下载文件
         * @param directory 下载目录
         * @param downloadFile 下载的文件名
         * @return 字节数组
         * @throws SftpException
         * @throws IOException
         * @throws Exception
         */
        public byte[] download(String directory, String downloadFile) throws SftpException, IOException{
        
            if (directory != null && !"".equals(directory)) {
        
                sftp.cd(directory);
            }
            InputStream is = sftp.get(downloadFile);
    
            byte[] fileData = IOUtils.toByteArray(is);
    
            log.info("file:{} is download successful" , downloadFile);
            return fileData;
        }
    
        /**
         * 删除文件
         *
         * @param directory
         *            要删除文件所在目录
         * @param deleteFile
         *            要删除的文件
         * @throws SftpException
         * @throws Exception
         */
        public void delete(String directory, String deleteFile) throws SftpException{
        
            sftp.cd(directory);
            sftp.rm(deleteFile);
        }
    
        /**
         * 列出目录下的文件
         *
         * @param directory
         *            要列出的目录
         * @return
         * @throws SftpException
         */
        public Vector<?> listFiles(String directory) throws SftpException {
        
            return sftp.ls(directory);
        }
    
        public static void main(String[] args) throws SftpException, IOException {
        
    //        SFTPUtil sftp = new SFTPUtil("user1", "123456", "192.168.0.244", 22);
    //        sftp.login();
    //        byte[] buff = sftp.download("/", "index.js");
    
    //        SFTPUtil sftp = new SFTPUtil("user", "123456", "192.168.0.162", 22);
    //        sftp.login();
    //        byte[] buff = sftp.download("/a", "ECDSAKey.cfg");
    //        System.out.println(new String(buff));
    
    //        File file = new File("C:\\Program Files (x86)\\NetSarang\\Xmanager Enterprise 4\\2.txt");
    //        InputStream is = new FileInputStream(file);
    //        sftp.upload("/usr/ywnysftp/upload/test", "csdn1.png", is);
    //        sftp.upload("/upload", "2.txt", is);
            // 下载，上面的是之前的测试案例
            SFTPUtil sftp = new SFTPUtil("user", "12345678", "192.168.0.64", 22);
            sftp.login();
            byte[] buff = sftp.download("/", "导入数据.xlsx");
            IOUtils.write(buff, new FileOutputStream("C:\\Users\\win20\\Desktop\\file\\导入数据.xlsx"));
            sftp.logout();
        }
    }

[freeSSHd.exe]: https://download.csdn.net/download/laolvbig/88135351
[364a20b14fa246dcbc89ea8aca442758.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/ea44bd971d2848409fa625070fe0ef34.png
[71b5fcb036b7459c920d2625dde2bf1f.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/f8c8e52b19e547bfbc373a251359021c.png
[70a5bd47e21d4b1b862e362493b8e2d0.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/d4292cce63fc4157b871de3f7fd343bc.png
[ace798661b9542e5bb67a3e59a013667.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/378a8feedde5496bb2c0319412d34a10.png
[8fd7e4f381e84cf1bd6810e919eab98b.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/bfd3db0d7c1d4d839d6ebe359da6bde2.png
[6a5fd3ce66654e8b8f4de1a663e69f07.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/46560f6b62864365943ac25e75f8dcb0.png
[3dc357601f1f48b4852300bb17ca600e.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/8b4db8978ac549a185bf59c99a7d18f6.png
[bcbabac4426545a6a5736f1467c91262.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/749911322da94cdfb05f2a4aa7cacee1.png
[bc9158c15531401283dc88081f572334.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/7b0bf51f445b4003a07f99985a1b31c6.png