java连接sftp服务器实现上传下载

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。
  
  

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
   
2. 按照步骤配置
   
   
   
   
   
3. unload之后重新打开，配置生效
   

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;public class SFTPUtil {    private transient Logger log = LoggerFactory.getLogger(this.getClass());    private ChannelSftp sftp;    private Session session;        private String username;        private String password;        private String privateKey;        private String host;        private int port;        public SFTPUtil(String username, String password, String host, int port) {        this.username = username;        this.password = password;        this.host = host;        this.port = port;    }        public SFTPUtil(String username, String host, int port, String privateKey) {        this.username = username;        this.host = host;        this.port = port;        this.privateKey = privateKey;    }    public SFTPUtil(){}        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()});        }    }        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");            }        }    }        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);    }        public void upload(String directory, String uploadFile) throws FileNotFoundException, SftpException{        File file = new File(uploadFile);        upload(directory, file.getName(), new FileInputStream(file));    }        public void upload(String directory, String sftpFileName, byte[] byteArr) throws SftpException{        upload(directory, sftpFileName, new ByteArrayInputStream(byteArr));    }        public void upload(String directory, String sftpFileName, String dataStr, String charsetName) throws UnsupportedEncodingException, SftpException{        upload(directory, sftpFileName, new ByteArrayInputStream(dataStr.getBytes(charsetName)));    }        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);    }        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;    }        public void delete(String directory, String deleteFile) throws SftpException{        sftp.cd(directory);        sftp.rm(deleteFile);    }        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();    }}

来源地址：https://blog.csdn.net/laolvbig/article/details/132024462