Explain the technical principles and optimization strategies of the "Disk Lru Cache" framework in the Java library

"Disk Lru Cache" in the Java class library is mainly used to cach data on disks and manage it.Its principle is to combine the LRU (Least Recently Use) algorithm and the idea of dying data to the disk.Maintain a fixed -size cache in the memory. When the cache space is insufficient, the recently used data that has been recently used by the LRU algorithm is eliminated from the cache, and these data are persisted to the disk. The core class of DISK LRU Cache is a two -way linked list of the LRU entry. Each node contains a key value pair and related pointer.The linked list is sorted according to the order of access. The recent access entries will be ranked in front of the linked list, and the minimum use entries will be ranked at the end of the linked list. When you need to read the cache data, Disk Lru Cache first finds the corresponding entries in the memory cache.If you find it, you will think that you cache and return the corresponding data directly.If it is not found, it needs to be loaded from the disk and put it into the memory cache. In the process, it will follow the latest use of the LRU algorithm to eliminate the memory cache at the least. When you need to write the cache data, the Disk Lru Cache will first write the data into the memory cache, and in this process, the memory cache is managed according to the LRU algorithm.The data is then used asynchronous to the disk to ensure the durable storage of the data. In order to further improve the cache performance, Disk Lru Cache also applied some optimization strategies.One of the optimization strategies is to set a threshold of the maximum cache size. When the cache size is close to the threshold, the cache cleaning operation will be triggered.On the disk, there is more cache space. In addition, DISK LRU Cache can also perform data expiration management by setting the time of the cache bar.When the expiration time of a entry exceeds the set threshold, it will be considered to be expired, and it will be eliminated during the next cache cleaning operation. In summary, the Disk Lru Cache framework uses the LRU algorithm and the duration of disk to achieve efficient data cache management, providing better performance and reliable data storage.By appropriate configuration and use, developers can easily use Disk Lru Cache in Java applications to improve the efficiency and response speed of data reading and writing operations.