如何将 hashmap 的小于 x 值的键放入数组列表中，以使其在每次键小于 x 值时重新生成 x 值

Question

我正在制作一个 Bukkit 插件，玩家可以在其中获得法力和法术。每个法术都有自己的法力消耗，玩家从 20 法力开始。

我有一个 ArrayList 用于存储法力值低于 20 的玩家，还有一个 HashMap 用于存储玩家当前的法力值。我需要知道如何制作一种方法，每秒为法力值低于 20 的玩家增加 1 法力值。

每次有玩家进入 ArrayList 时我都需要这样做，然后在他们达到 20 法力值时将他们从列表中删除。

这是我当前的代码：

public HashMap<String, Integer> mana = new HashMap<String, Integer>();
public ArrayList<String> changedMana = new ArrayList<String>();

public void onManaChange(){
  //code goes here
}

Answer 1

将其更改为 TreeMap 并使用 headMap() method。

Answer 2

您可以每秒运行一个任务计时器（这应该放在您的 onEnable() 方法中）：

Bukkit.getServer().getScheduler().runTaskTimer(plugin, new Runnable(){
    public void run(){

    }
},20L,20L); //run this task every 20 ticks (20 ticks = 1 second)

并为 ArrayList:

中的玩家增加魔法值

List<String> toRemove = new ArrayList<String>();

for(String player : changedMana){ //loop through all of the players in the ArrayList
   int current = mana.get(player); //get the player's current mana
   if(current < 20){ //if the player's mana is less than 20
       current++; //add to the player's mana
       mana.put(player, current); //update the player's mana
   }
   else if(current == 20){ //if the player's mana is greater than or equal to 20
       toRemove.add(player); //add the player to the toRemove list, in order to remove the player from the ArrayList later safely
   }
   else{
     //do something if the current mana is > 20, if you don't want to, just remove this
   }
}

changedMana.removeAll(toRemove); //remove players from the changed mana array

那么，如果代码在您的 Main class（extends JavaPlugin 中），您的代码可能会是这样的：

public HashMap<String, Integer> mana = new HashMap<String, Integer>();
public ArrayList<String> changedMana = new ArrayList<String>();

@Override
public void onEnable(){
  Bukkit.getServer().getScheduler().runTaskTimer(plugin, new Runnable(){
    public void run(){
      List<String> toRemove = new ArrayList<String>();

      for(String player : changedMana){ //loop through all of the players in the ArrayList
        int current = mana.get(player); //get the player's current mana
        if(current < 20){ //if the player's mana is less than 20
           current++; //add to the player's mana
           mana.put(player, current); //update the player's mana
        }
        else if(current == 20){ //if the player's mana is greater than or equal to 20
           toRemove.add(player); //add the player to the toRemove list, in order to remove the player from the ArrayList later safely
        }
        else{
           //do something if the current mana is > 20, if you don't want to, just remove this
        }
      }

      changedMana.removeAll(toRemove); //remove players from the changed mana array
    }
  },20L,20L);
}

如何将 hashmap 的小于 x 值的键放入数组列表中，以使其在每次键小于 x 值时重新生成 x 值

How to get the keys of the hashmap that have less than x value into an arraylist to make it regen to x value everytime the keys get less than x value

java

arraylist

hashmap

bukkit