java - 如何更新Java HashTable？

Question

我有两个哈希表和一个链接列表，顺序如下:

Hashtable<Character, Hashtable<String, LinkedList<String>>> hashTab = new Hashtable(); 
Hashtable<String, LinkedList<String>> string_list = new Hashtable();
LinkedList<String> data_list = new LinkedList();

现在我有一个函数，通过它我可以在哈希表和链接列表中传递值

public String createPlayerAccount(String FirstName, String LastName, int Age, String Username, String Password, String IPAddress)
{
    char username_first_char = Username.charAt(0);

    try
    {
        boolean username_exists = hashTab.get(username_first_char).containsKey(Username);
        if(!username_exists)
        {
            String data_string = FirstName + " " + LastName + " " + Age + " " + Password + " " + IPAddress + playerStatus; //Pass user details to a string
            data_list.add(data_string);  //Add user details to the linked list
            string_list.put(Username, data_list);
            hashTab.put(username_first_char, string_list);
            return("Dear " + FirstName + ",  You have successfully registered");
        }
        else
        {
            return("Username already exists");
        }   
    }
    catch(Exception e)
    {
        String data_string = FirstName + " " + LastName + " " + Age + " " + Password + " " + IPAddress +" "+ playerStatus; //Pass user details to a string
        data_list.add(data_string);  //Add user details to the linked list
        string_list.put(Username, data_list);
        hashTab.put(username_first_char, string_list);
        return("Username successfully added \n ");
    }
}

playerStatus 默认设置为 0。现在我正在为 Signin() 创建另一个函数，其中我希望将 playerStatus 的值更新为 1。我应该做什么？

登录():

public String playerSignIn(String Username, String Password, String IPAddress)
{
    char username_first_char = Username.charAt(0);
    try
    {
        String user_profile;
        boolean username_exists = hashTab.get(username_first_char).containsKey(Username);
        if(username_exists)
        {
            playerStatus = "1";
            //String data_string = Password + " " + IPAddress +" "+ playerStatus; //Pass user details to a string
            //data_list.add(data_string);  //Add user details to the linked list
            //string_list.put(Username, data_list);
            //hashTab.put(username_first_char, string_list);  //Add user details to the linked list
            //return();
            //hashTab.put(username_first_char, string_list);
            //user_profile = hashTab.get(username_first_char).get(Username).get(0);
            return(user_profile);
            /*String data_string = Username + " " + Password + " " + IPAddress +" "+ "1"; //Pass user details to a string
            data_list.add(data_string);  //Add user details to the linked list
            string_list.put(Username, data_list);
            hashTab.put(username_first_char, string_list); 

            String get_user_data = hashTab.get(username_first_char).get(Username).get(0);
            String[] user_record = get_user_data.split(" ");
            String users_status = user_record[5];*/

            //return("User status updated: " + user_record[5]);
        }
        else
        {
            return("Invalid username or password");
        }
    }
    catch(Exception e)
    {
        return("PAWNED");
    }
}

注意:这是代码的服务器端。我正在制作一个客户端-服务器分布式系统。

Answer 1

正如评论中提到的，您需要创建一个 POJO(对象类)来保存有关给定玩家的信息。我将该类命名为 Player。如果您需要一个包含玩家信息的字符串，以便发送到客户端，只需在 Player 类上使用 toString() 方法即可。

当我开发多人游戏时，在服务器端我通常使用 ConcurrentHashMap 来存储信息。如果您使用的消息传递系统需要哈希表，那么您将会遇到同步问题，如果您不知道自己在做什么，这可能会导致死锁。

开始重构您的代码。使用 Player 类后，代码应该更具可读性，并且您应该能够发现另一个 POJO 也可能有用的地方。