SFTPUtils

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.Properties;
import java.util.Vector;

import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.jcraft.jsch.Channel;
import com.jcraft.jsch.ChannelSftp;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.Session;
import com.jcraft.jsch.SftpATTRS;
import com.jcraft.jsch.SftpException;

public class SFTPUtils {

    private final 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 SFTPUtils(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 SFTPUtils(String username, String host, int port, String privateKey) {
        this.username = username;
        this.host = host;
        this.port = port;
        this.privateKey = privateKey;
    }

    public SFTPUtils() {
    }

    /**
     * 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 : {}:{}  Exception message is: {}", 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 in           输入流
     * @throws SftpException
     * @throws Exception
     */
    public void upload(String directory, String sftpFileName, InputStream input) throws SftpException {
        try {
            // 目录不存在则创建目录
            createDir(directory);
            sftp.cd(directory);
            sftp.put(input, sftpFileName);
        } catch (SftpException e) {
            log.warn("directory is not exist");
            sftp.mkdir(directory);
            sftp.cd(directory);
            sftp.put(input, sftpFileName);
        } finally {
            try {
                if (input != null) {
                    input.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        log.info("file:{} is upload successful", sftpFileName);
    }


    /**
     * 创建一个文件目录
     */
    public void createDir(String createpath) {
        try {
            if (isDirExist(createpath)) {
                return;
            }
            String[] pathArry = createpath.split("/");
            StringBuilder filePath = new StringBuilder("/");
            for (String path : pathArry) {
                if (path.equals("")) {
                    continue;
                }
                filePath.append(path).append("/");
                if (isDirExist(filePath.toString())) {
                } else {
                    // 建立目录
                    sftp.mkdir(filePath.toString());

                }
            }

        } catch (SftpException e) {
            log.error("创建文件失败");
        }
    }


    /**
     * 判断目录是否存在
     */
    public boolean isDirExist(String directory) {
        boolean isDirExistFlag = false;
        try {
            SftpATTRS sftpATTRS = sftp.lstat(directory);
            isDirExistFlag = true;
            return sftpATTRS.isDir();
        } catch (Exception e) {
            if (e.getMessage().toLowerCase().equals("no such file")) {
                isDirExistFlag = false;
            }
        }
        return isDirExistFlag;
    }


    /**
     * 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
     * @param sftp
     * @return
     * @throws SftpException
     */
    public Vector<?> listFiles(String directory) throws SftpException {
        return sftp.ls(directory);
    }


}