1. 用Java图形用户界面编写聊天室服务器端和客户端， 支持多个客户端连接到一个服务器。每个客户端能够输入账号。
2. 可以实现群聊（聊天记录显示在所有客户端界面）。
3. 完成好友列表在各个客户端上显示。
4. 可以实现私人聊天，用户可以选择某个其他用户，单独发送信息。
5. 服务器能够群发系统消息，能够强行让某些用户下线。
6. 客户端的上线下线要求能够在其他客户端上面实时刷新。(1. use the Java graphical user interface to write the chat room server side and the client, supporting multiple clients to connect to a server. Each client is able to enter the account.

2. can achieve group chat (chat records are displayed on all client interfaces).

3. complete the list of friends displayed on each client.

4. can realize private chat, the user can choose one other user and send the information separately.

5. servers can send system messages in group, and can forcibly let some users down.

The 6. client's online downline needs to be refreshed in real time on other clients.)