java sftp determine whether a directory exists

java sftp determine whether a directory exists

public boolean isExistDir(String path,ChannelSftp sftp){
        boolean  isExist=false;
        try {
            SftpATTRS sftpATTRS = sftp.lstat(path);
            isExist = true;
            return sftpATTRS.isDir();
        } catch (Exception e) {
            if (e.getMessage().toLowerCase().equals("no such file")) {
                isExist = false;
            }
        }
        return isExist;

    }

Complete sftpUtil.class

package com.iot.crm.common.util;

import com.jcraft.jsch.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.*;
import java.util.Properties;


public class SftpUtils {
    
    final Logger logger = LoggerFactory.getLogger(SftpUtils.class);

    protected String host;
    protected int port;
    protected String username;
    protected String password;
    Session sshSession = null ;

    /**
     * @param host ip
     * @param port 端口
     * @param username 账号
     * @param password 密码
     */
    public SftpUtils(String host, int port, String username, String password) {
        set(host, port, username, password);
    }

    public void set(String host, int port, String username, String password) {
        this.host = host;
        this.port = port;
        this.username = username;
        this.password = password;
    }

    public Session getSession() {
        //Session sshSession = null;
        try {
            JSch jsch = new JSch();
            jsch.getSession(this.username, this.host, this.port);
            sshSession = jsch.getSession(this.username, this.host, this.port);
            System.out.println("Session created.");
            sshSession.setPassword(this.password);
            Properties sshConfig = new Properties();
            sshConfig.put("StrictHostKeyChecking", "no");
            sshSession.setConfig(sshConfig);
            sshSession.connect();
            System.out.println("Session connected.");
            System.out.println("Opening Channel.");
        } catch (Exception e) {
            e.printStackTrace();
        }
        return sshSession;
    }
    /**
    /**
     * 链接linux
     */
    public ChannelSftp connectSftp() {
        getSession();
        ChannelSftp sftp = null;
        try {
            System.out.println("Session connected.");
            System.out.println("Opening Channel.");
            Channel channel = sshSession.openChannel("sftp");
            channel.connect();
            sftp = (ChannelSftp) channel;
        } catch (Exception e) {
            e.printStackTrace();
            sftp = null;
        }
        return sftp;
    }

    public void exec(Session session,String command) {
        ChannelExec channelExec = null;
        try {
            System.out.println("Session connected.");
            System.out.println("Opening Channel.");
            Channel channel = session.openChannel("exec");
            channelExec = (ChannelExec) channel;
            channelExec.setCommand(command);
            channelExec.connect();
            channelExec.setInputStream(null);
            InputStream in = channelExec.getInputStream();
            BufferedReader reader = new BufferedReader(new InputStreamReader(in));
            String buf = null;
            while ((buf = reader.readLine()) != null)
            {
                System.out.println(buf);
            }
            reader.close();
        } catch (Exception e) {
            e.printStackTrace();
            channelExec = null;
        }finally {
            channelExec.disconnect();
        }
    }



    /**
     * linux上传文件
     */
    public void upload(String directory, File file) {
        ChannelSftp sftp = connectSftp();
        try {
            if (null != sftp) {
                sftp.cd(directory);
                logger.info("cd {}", directory);
                FileInputStream stream = new FileInputStream(file);
                try {
                    sftp.put(stream, file.getName());
                } catch (Exception e) {
                    logger.error("upload error", e);
                } finally {
                    stream.close();
                }
            }
        } catch (Exception e) {
            logger.error("upload:" + host, e);
        } finally {
            if (sftp != null) {
                sftp.disconnect();
                sftp.exit();
            }
            sshSession.disconnect();
        }
    }

    /**
     * linux下载文件
     */
    public void get(String remotePath,String remoteFilename,String localFileName) {
        ChannelSftp sftp = connectSftp();
        File file=null;
        OutputStream output=null;
        try {
            if (null != sftp) {
                 file = new File(localFileName);
                if (file.exists()){
                    file.delete();
                }
                file.createNewFile();
                sftp.cd(remotePath);

                output=new FileOutputStream(file);
                try {
                    logger.info("Start download file:{},the arm file name:{}",remotePath+remoteFilename,localFileName);
                    sftp.get(remoteFilename, output);
                    logger.info("down {} suc", remotePath+remoteFilename);
                } catch (Exception e) {
                    logger.error("download error", e);
                } finally {
                    output.close();
                }
            }
        } catch (Exception e) {
            logger.error("down error :" , e);
        } finally {
            close(sftp);
        }
    }

    protected void close(ChannelSftp sftp) {
        if (sftp != null) {
            sftp.disconnect();
            sftp.exit();
        }
        if (sshSession != null) {
            sshSession.disconnect();
        }
    }

   

}