现有需求将文件从FTP服务器上进行上传下载，看网上使用了org.apache.commons.net.ftp.FTPClient类，但通过该类连接FTP会报一个Could not parse response code.Server Reply: SSH-2.0-OpenSSH_5.3这样的错误，原因是它不支持这种方式的连接(使用FTPSClient的SSL也是不行的)，所以现在换新的工具，使用ChannelSftp来实现该功能。
上代码：根据实际情况略作修改
pom文件：
<dependency><groupId>com.jcraft</groupId><artifactId>jsch</artifactId><version>0.1.54</version>
</dependency>默认编码是UTF-8
@Slf4j
@Component
public class FtpJSch {/*缺关闭连接*/private static ChannelSftp sftp = null;private static Channel channel=null;private static Session sshSession=null;//账号private static String user = "";//主机ipprivate static String host = "";//密码private static String password = "";//端口private static int port = 22;//上传地址private static String directory = "";//下载目录private static String saveFile = "";public static void getConnect(){try {JSch jsch = new JSch();//获取sshSession 账号-ip-端口sshSession =jsch.getSession(user, host,port);//添加密码sshSession.setPassword(password);Properties sshConfig = new Properties();//严格主机密钥检查sshConfig.put("StrictHostKeyChecking", "no");sshSession.setConfig(sshConfig);//开启sshSession链接sshSession.connect();//获取sftp通道channel = sshSession.openChannel("sftp");//开启channel.connect();sftp = (ChannelSftp) channel;} catch (Exception e) {e.printStackTrace();}}/**** @param uploadFile 上传文件的路径* @return 服务器上文件名*/public String upload(String uploadFile) {getConnect();File file = null;String fileName = null;try {sftp.cd(directory);file = new File(uploadFile);//获取随机文件名fileName = UUID.randomUUID().toString() + file.getName().substring(file.getName().length()-5);//文件名是 随机数加文件名的后5位sftp.put(new FileInputStream(file), fileName);} catch (Exception e) {e.printStackTrace();}closeChannel(channel);closeSession(sshSession);return file == null ? null : fileName;}/*** 下载文件*/public void download(String downloadFileName) {try {getConnect();sftp.cd(directory);File file = new File(saveFile+File.separator+downloadFileName);sftp.get(downloadFileName, new FileOutputStream(file));closeChannel(channel);closeSession(sshSession);} catch (Exception e) {e.printStackTrace();}}/*** 删除文件** @param deleteFile* 要删除的文件名*/public void delete(String deleteFile) {try {sftp.cd(directory);sftp.rm(deleteFile);} catch (Exception e) {e.printStackTrace();}}/*** 列出目录下的文件** 要列出的目录* @return* @throws SftpException*/public Vector listFiles()throws SftpException {getConnect();Vector ls = sftp.ls(directory);closeChannel(channel);closeSession(sshSession);return ls;}private static void closeChannel(Channel channel) {if (channel != null) {if (channel.isConnected()) {channel.disconnect();}}}private static void closeSession(Session session) {if (session != null) {if (session.isConnected()) {session.disconnect();}}}
}