我正在尝试使用“Apache FTP Server”创建一个具有内置/嵌入式FTP服务器的应用程序。我选择从MySQL数据库管理/验证用户。因此，我使用DbUserManager来处理用户创建，删除和列表。我能够管理除身份验证之外的所有用户相关操作。我无法从FTP客户端登录。服务器甚至不询问密码，只是给出消息“连接由远程主机关闭”。还有一个观察结果是 - 如果用户不在DB中，那么它要求输入密码，但最终会给出身份验证失败的消息。

这是代码，

public class Dumper {

/**

* @param args the command line arguments

*/

public static void main(String[] args) {

FtpServerFactory serverFactory;

FtpServer server;

ConnectionConfigFactory connectionConfigFactory;

ConnectionConfig connectionConfig;

DbUserManagerFactory userManagerFactory;

DbUserManager userManager;

BasicDataSource bdSource;

final Map ftpletMap;

Ftplet ftplet;

// TODO code application logic here

System.out.println("I am Dumper!!");

connectionConfigFactory = new ConnectionConfigFactory();

connectionConfigFactory.setAnonymousLoginEnabled(true);

connectionConfig = connectionConfigFactory.createConnectionConfig();

ftpletMap = new HashMap<>();

ftplet = new DumperLet();

ftpletMap.put("default", ftplet);

// Data Source

bdSource = new BasicDataSource();

bdSource.setDriverClassName("com.mysql.cj.jdbc.Driver");

bdSource.setUrl("jdbc:mysql://localhost:3306/apsdma");

bdSource.setUsername("apsdma");

bdSource.setPassword("apsdma");

// Database User Manager

userManagerFactory = new DbUserManagerFactory();

userManagerFactory.setPasswordEncryptor(new Md5PasswordEncryptor());

userManagerFactory.setAdminName("ambedkar");

userManagerFactory.setDataSource(bdSource);

userManagerFactory.setSqlUserInsert("INSERT INTO FTP_USER (userid, userpassword, homedirectory, enableflag, writepermission, idletime,uploadrate, downloadrate) VALUES ('{userid}', '{userpassword}', '{homedirectory}', {enableflag}, {writepermission}, {idletime}, {uploadrate}, {downloadrate})");

userManagerFactory.setSqlUserUpdate("UPDATE FTP_USER SET userpassword='{userpassword}', homedirectory='{homedirectory}', enableflag={enableflag}, writepermission={writepermission}, idletime={idletime}, uploadrate={uploadrate}, downloadrate={downloadrate} WHERE userid='{userid}'");

userManagerFactory.setSqlUserDelete("DELETE FROM FTP_USER WHERE userid = '{userid}'");

userManagerFactory.setSqlUserSelect("SELECT userid, userpassword, homedirectory, enableflag, writepermission, idletime, uploadrate, downloadrate FROM FTP_USER WHERE userid = '{userid}'");

userManagerFactory.setSqlUserSelectAll("SELECT userid FROM FTP_USER ORDER BY userid");

userManagerFactory.setSqlUserAdmin("SELECT userid FROM FTP_USER WHERE userid='{userid}' AND userid='ambedkar'");

userManagerFactory.setSqlUserAuthenticate("SELECT userpassword from FTP_USER WHERE userid='{userid}'");

userManager = (DbUserManager) userManagerFactory.createUserManager();

serverFactory = new FtpServerFactory();

serverFactory.setConnectionConfig(connectionConfig);

serverFactory.setFtplets(ftpletMap);

serverFactory.setUserManager(userManager);

server = serverFactory.createServer();

try {

server.start();

} catch (FtpException ex) {

Logger.getLogger(Dumper.class.getName()).log(Level.SEVERE, null, ex);

System.out.println(ex.getMessage());

}

}

}

这是客户端输出的屏幕截图，

有人可以指导我出了什么问题或在哪里寻找解决方案，请...