Java 如何将hashmap中小于x值的键放入arraylist，使其在每次键小于x值时都重新生成x值

我正在制作一个Bukkit插件，玩家可以使用法力和法术。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

存储法力低于20的玩家，还有一个

HashMap

存储玩家当前的法力。我需要知道如何制作一种方法，在玩家的魔法值低于20的情况下，每秒增加1点魔法值

每次玩家进入

ArrayList

时，我都需要这样做，当他们达到20法力值时，我会将他们从列表中删除

这是我目前的代码：

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

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

public HashMap mana=new HashMap（）；
public ArrayList changedMana=new ArrayList（）；
公共管理变更（）{
//代码在这里
}

将其更改为一个

树状图，并使用。
您可以每秒运行一次任务计时器（这应该放在您的
onEnable（）方法中）：

并向
阵列列表中的玩家添加法力：

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

你能简单地解释一下你的问题吗。我认为这些
法力
&
法术
的措辞让问题变得有点复杂。好吧，有些法术需要消耗法力，施放法术需要法力…为什么？有什么区别吗？树状图有保证的顺序，而散列图没有t@L3n因为
Treemap
具有
headMap（）
方法，而
HashMap
则没有。“Iterator.remove”是在迭代过程中修改集合的唯一安全方法；如果在迭代过程中以任何其他方式修改基础集合，则该行为未指定。
if（current>=20）
检查非常丰富，因为唯一可能的fall-through-from
if（current<20）else
已与条件匹配。代码也是次优的，因为构造了一个新的
列表
来处理从原始
列表
中删除的第二个循环，其中as
removeAll
会做得很好-尽管最佳方法是只使用
迭代器
并使用
else迭代器.remove（）
，它节省了对象构造，并且易于维护。
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

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);
}