什么是 "LoadingCache"？
What is a "LoadingCache"?
Google提供了一个“loading cache”，描述如下：
A semi-persistent mapping from keys to values. Values are automatically loaded by the cache, and are stored in the cache until either evicted or manually invalidated.
不幸的是，上面的描述不是很清楚。 "automatically loaded" 是什么意思？
我希望这意味着："If a requested key does not exist in the cache, it is then added to it automatically"。
以下语句（来自 get() 函数）在一定程度上支持了这一点：
"Returns the value associated with in this cache, first loading that
value if necessary."
但同样，缓存的 "loading" 方面用 "loading" 一词解释。干得好，Google :[
Guava 的 wiki 文档有一个 full definition：（重点是我的）
A LoadingCache is a Cache built with an attached CacheLoader. Creating a CacheLoader is typically as easy as implementing the method V load(K key) throws Exception. So, for example, you could create a LoadingCache with the following code:
[...]
The canonical way to query a LoadingCache is with the method get(K). This will either return an already cached value, or else use the cache's CacheLoader to atomically load a new value into the cache. Because CacheLoader might throw an Exception, LoadingCache.get(K) throws ExecutionException. If you have defined a CacheLoader that does not declare any checked exceptions then you can perform cache lookups using getUnchecked(K); however care must be taken not to call getUnchecked on caches whose CacheLoaders declare checked exceptions.
强调的句子解释了所有需要解释的内容：一个值要么从缓存中取出，要么在调用get(K)时加载。
在评论中你说你想更加强调什么是 loading。当你把东西放入缓存时，你放。当你不把东西放在缓存中，但缓存会计算并自己放入时，缓存 会为你加载。
Google提供了一个“loading cache”，描述如下：
A semi-persistent mapping from keys to values. Values are automatically loaded by the cache, and are stored in the cache until either evicted or manually invalidated.
不幸的是，上面的描述不是很清楚。 "automatically loaded" 是什么意思？
我希望这意味着："If a requested key does not exist in the cache, it is then added to it automatically"。
以下语句（来自 get() 函数）在一定程度上支持了这一点：
"Returns the value associated with in this cache, first loading that value if necessary."
但同样，缓存的 "loading" 方面用 "loading" 一词解释。干得好，Google :[
Guava 的 wiki 文档有一个 full definition：（重点是我的）
A
LoadingCacheis aCachebuilt with an attachedCacheLoader. Creating aCacheLoaderis typically as easy as implementing the methodV load(K key) throws Exception. So, for example, you could create aLoadingCachewith the following code:[...]
The canonical way to query a
LoadingCacheis with the methodget(K). This will either return an already cached value, or else use the cache'sCacheLoaderto atomically load a new value into the cache. BecauseCacheLoadermight throw anException,LoadingCache.get(K)throwsExecutionException. If you have defined aCacheLoaderthat does not declare any checked exceptions then you can perform cache lookups usinggetUnchecked(K); however care must be taken not to callgetUncheckedon caches whoseCacheLoaders declare checked exceptions.
强调的句子解释了所有需要解释的内容：一个值要么从缓存中取出，要么在调用get(K)时加载。
在评论中你说你想更加强调什么是 loading。当你把东西放入缓存时，你放。当你不把东西放在缓存中，但缓存会计算并自己放入时，缓存 会为你加载。