更新活动频道的JList时出现问题

介绍：

我创建了一个聊天程序，客户端连接服务器。 客户端能够加入通道，当它们这样做时，jList（请参阅代码）应该通过DefaultListModel更新（getChannel（）），并且应该显示连接到同一通道的所有其他客户端。 我知道getChannel（）; 工作，因为我已经调试它（并使用systemoutprint）。 我已经有活动频道和用户在线的Jlists，这有效！ 🙂

客户端使用回调方法通知连接到服务器的其他客户端。

我已经完成了一些调试，而且我一直在尝试重复我的代码。

inheritance人代码：

服务器：

private Hashtable<String, ArrayList> channels = new Hashtable<String, ArrayList>(); public void connectChannel(String username, String channel) throws RemoteException{ setUsername(username); if(isUserRegistered(username)){ if (!channels.containsKey(channel)) { String message = "User " + username + " entered the channel"; channels.put(channel, new ArrayList()); channels.get(channel).add(username); notifyChannelSystem(channel, "SYSTEM", message); notifySelf(username, "Write /? for avaliable commands"); System.out.println("User " + username + " connected to channel " + channel + " which was created"); } else{ if(channels.get(channel).contains(username)){ notifySelf(username, "Place in channel " + channel); System.out.println("User " + username + " connected to channel " + channel + " which the user was already in"); } else { channels.get(channel).add(username); String message = "User " + username + " just entered the channel"; notifyChannelSystem(channel, "SYSTEM", message); System.out.println("User " + username + " connected to channel " + channel + " which was already created by someone else"); } } } updateJListForActiveChannels(); updateJListForUsersInChannel(); } @Override public ArrayList getUsersInChannel(String channel) throws RemoteException{ return channels.get(channel); } @Override public void updateJListForUsersInChannel() throws RemoteException{ for(Client c : clients){ c.getJListForUsersInChannel(); } } 

GUILogic：

 DefaultListModel usersInChanDLM = new DefaultListModel(); public ArrayList getUsersInChannel(String channel) throws RemoteException{ return cf.getUsersInChannel(channel); } public DefaultListModel getUsersInChannelAsDefaultListModel(String channel) throws RemoteException{ if(!(getChannel() == null)){ for(String a : cf.getUsersInChannel(getChannel())){ usersInChanDLM.addElement(a); } } return usersInChanDLM; } void updateUsersInChannelJlist(JList jList3) throws RemoteException { usersInChanDLM.clear(); for(Client c : cf.getClients()){ if(!(usersInChanDLM.contains(c.findName()))){ usersInChanDLM.addElement(c.findName()); } } jList3.setModel(usersInChanDLM); } 

GUI：jList：

 usersInChannelJList = new javax.swing.JList(); try{ usersInChannelJList.setModel(gl.getUsersInChannelAsDefaultListModel(gl.getChannel())); usersInChannelJList.setSelectionMode(javax.swing.ListSelectionModel.SINGLE_SELECTION); }catch(RemoteException ex){ System.out.println(ex); } jScrollPane4.setViewportView(usersInChannelJList); 

接口：

服务器：

  void updateJListForUsersInChannel() throws RemoteException; 

客户：

  void getJListForUsersInChannel() throws RemoteException; 

**

问题：

**

JList显示了此刻连接的所有用户，我猜这是因为这种方法

 public ArrayList getUsersInChannel(String channel) throws RemoteException{ return channels.get(channel); } 

我想要做的是从所选频道获取一个包含所有用户的数组。 有没有简单的方法从频道哈希表中做到这一点？