基于Java的时间映射/缓存与过期的密钥(Java time-based map/cache with expiring keys [closed])
你们中有谁知道Java Map或类似的标准数据存储，在给定的超时后自动清除条目？ 这意味着老化，旧的过期条目“老化”自动。
最好在通过Maven访问的开源库中？
我知道自己实现功能的方法，并且在过去已经做了好几次，所以我不是在这方面要求建议，而是指向一个很好的参考实现。
WeakHashMap等基于WeakReference的解决方案不是一个选择，因为我的密钥很可能是非内部的字符串，我想要一个不依赖于垃圾收集器的可配置超时。
Ehcache也是一个我不想依赖的选项，因为它需要外部配置文件。 我正在寻找一个代码解决方案。
Do any of you know of a Java Map or similar standard data store that automatically purges entries after a given timeout? This means aging, where the old expired entries “age-out” automatically.
Preferably in an open source library that is accessible via Maven?
I know of ways to implement the functionality myself and have done it several times in the past, so I'm not asking for advice in that respect, but for pointers to a good reference implementation.
WeakReference based solutions like WeakHashMap are not an option, because my keys are likely to be non-interned strings and I want a configurable timeout that's not dependent on the garbage collector.
Ehcache is also an option I wouldn't like to rely on because it needs external configuration files. I am looking for a code-only solution.
原文：https://stackoverflow.com/questions/3802370
更新时间：2023-09-16 19:09
最满意答案
其实你很接近你的目标，你只需要使用nodes（）方法来分割你的行，然后获取值：
select s.SqmId, m.c.value('@id', 'varchar(max)') as id, m.c.value('@type', 'varchar(max)') as type, m.c.value('@unit', 'varchar(max)') as unit, m.c.value('@sum', 'varchar(max)') as [sum], m.c.value('@count', 'varchar(max)') as [count], m.c.value('@minValue', 'varchar(max)') as minValue, m.c.value('@maxValue', 'varchar(max)') as maxValue, m.c.value('.', 'nvarchar(max)') as Value, m.c.value('(text())[1]', 'nvarchar(max)') as Value2 from sqm as s outer apply s.data.nodes('Sqm/Metrics/Metric') as m(c)sql小提琴演示
Actually you're close to your goal, you just need to use nodes() method to split your rows and then get values:
select s.SqmId, m.c.value('@id', 'varchar(max)') as id, m.c.value('@type', 'varchar(max)') as type, m.c.value('@unit', 'varchar(max)') as unit, m.c.value('@sum', 'varchar(max)') as [sum], m.c.value('@count', 'varchar(max)') as [count], m.c.value('@minValue', 'varchar(max)') as minValue, m.c.value('@maxValue', 'varchar(max)') as maxValue, m.c.value('.', 'nvarchar(max)') as Value, m.c.value('(text())[1]', 'nvarchar(max)') as Value2 from sqm as s outer apply s.data.nodes('Sqm/Metrics/Metric') as m(c)
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