jsch连接sftp后连接未释放掉问题排查

@Repository("SftpClient")
public class SftpClient {

    private Logger logger = LoggerFactory.getLogger(SftpClient.class);  
    private ThreadLocal<Session> sessionLocal = new ThreadLocal<Session>(); 
    private ThreadLocal<ChannelSftp> channelLocal = new ThreadLocal<ChannelSftp>();
    
    //初始化连接
    public SftpClient init() {
        try {
            String host = SFTP_HOST;
            int port = Integer.valueOf(SFTP_PORT);
            String userName = SFTP_USER_NAME;
            String password = SFTP_USER_PASSWORD;
            Integer timeout = Integer.valueOf(SFTP_TIMEOUT);
            Integer aliveMax = Integer.valueOf(SFTP_ALIVEMAX);
            // 创建JSch对象
            JSch jsch = new JSch();
            Session session = jsch.getSession(userName, host, port);
            // 根据用户名，主机ip，端口获取一个Session对象
            if (password != null) {
                // 设置密码
                session.setPassword(password);
            }
            // 为Session对象设置properties
            session.setConfig("StrictHostKeyChecking", "no");
            if (timeout != null) {
                // 设置timeout时间
                session.setTimeout(timeout);
            }
            if (aliveMax != null) {
                session.setServerAliveCountMax(aliveMax);
            }
            // 通过Session建立链接
            session.connect();
            // 打开SFTP通道
            ChannelSftp channel = (ChannelSftp) session.openChannel("sftp");
            // 建立SFTP通道的连接
            channel.connect();
            channelLocal.set(channel);
            sessionLocal.set(session);
            logger.debug("SSH Channel connected.session={},channel={}", session, channel);
        } catch (JSchException e) {
            throw new SystemException(ImageExceptionCode.FTP_SEND_ERROR);
        }
        return this;
    }

    //断开连接
    public void disconnect() {
        ChannelSftp channel = channelLocal.get();
        Session session = sessionLocal.get();
        //断开sftp连接
        if (channel != null) {
            channel.disconnect();
            logger.debug("SSH Channel disconnected.channel={}", channel);
        }
        //断开sftp连接之后，再断开session连接
        if (session != null) {
            session.disconnect();
            logger.debug("SSH session disconnected.session={}", session);
        }
        channelLocal.remove();
        sessionLocal.remove();
    }
}