带有定时/瞬态条目的映射 - 内存不是问题
我正在尝试创建一个地图，其中条目会超时并在一定时间段后被删除。
基本上，
例如：map.put("foo", "bar", 60l * 1000l) 会让这个键值对在地图中生存一分钟（60long 和 1000long）。
尝试：使用 ConcurentMap 并通过以下方式实现 Map.put(K key, V value, long **time**)：
1. 调用super.put(key, value)
2. 创建一个休眠时间（毫秒）的线程
3. 调用remove(key)删除该条目。
问题：请发表评论/让我知道这在线程安全性、一致性或我的尝试中是否存在任何缺陷方面是否是一个好主意。如果您认为有更好的方法来实现此目的，请提供任何建议。
编辑：感谢您的回复，内存不是这里的问题，我真的只关心条目的短暂寿命。谢谢。
I'm trying to create a map in which the entries time out and get removed after a certain time period.
Basically, <K, V> Map.put(K key, V value, long **time**) - the entry will be put in the map instantly and will expire after time (ms). I do not need to recover the removed entry at any point in the future but I would like to make sure it's no longer in the map.
For example: map.put("foo", "bar", 60l * 1000l) will let this key-value pair live in the map for a minute (60long and 1000long).
Attempt: use a ConcurentMap and implement Map.put(K key, V value, long **time**) via the following:
1. call super.put(key, value)
2. create a thread that sleeps for time (ms)
3. call remove(key) to remove the entry.
Question: please comment/let me know whether this is a good idea in terms of thread-safety, consistency or any flaws in my attempt. If you think there's a better way to accomplish this, please provide any advice.
Edit: Thanks for the replies, memory is not the issue here, I really only care about the short life-span of the entries. Thank you.
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时间是您要解决的问题的重要组成部分吗？或者它是一个实施细节？如果您要解决的问题是内存使用问题，那么另外两种可能性就会浮现在脑海中：
编辑
在这种情况下，一些现有的实现可能会节省您一些时间。例如：
Is the time an essential part of the problem you're solving? Or is it an implementation detail? If the problem you're solving is one of memory use, two other possibilities spring to mind:
EDIT
In that case, there are some existing implementations that might save you some time. For instance:
如果您这样做是因为某些内存问题（地图是临时缓存），您可能应该考虑使用软引用（文档）。
If you are doing this because of some memory issue (the map is a temporal cache), you should probably consider using soft references (documentation).
查看番石榴 - 这是 Google 的一个收藏库。特别是，您需要查看 CacheBuilder 及其计算图。它的功能之一是“基于时间的条目过期，自上次访问或上次写入以来测量”，听起来正是您正在寻找的。
（编辑讨论 CacheBuilder；自从我发布此内容以来它是新的并且与问题更相关）
Take a look at Guava - it's a collection library from Google. In particular, you want to look at CacheBuilder and its computing maps. One of its features is "time-based expiration of entries, measured since last access or last write", sounds like exactly what you're looking for.
(Edited to talk about CacheBuilder; it's new since I posted this and is more relevant to the question)