Detailed explanation of the technical principles of the "DISK LRU CACHE" framework in the Java class library introduction: During the development process, we often need to cache some data to improve the performance and response speed of the system.However, as the amount of data increases, the cache in memory may not meet the demand.Therefore, we need a cache framework that can store data to the hard disk.The "Disk Lru Cache" framework in the Java class library is designed for this. Overview: "DISK LRU CACHE" is a framework for caching data. By storing data on the hard disk, memory consumption is effectively reduced.It uses the LRU (recently used) algorithm to manage the data in the cache to ensure that the latest data is always kept in the cache. Technical principle: 1. Storage structure: The "Disk Lru Cache" framework uses a two -way linked list to maintain the order of data in the cache.The head of the linked list is the recent data, and the tail of the linked list is the longest unused data.Each node saves the keys and values of the data, and the pointer to the front node and the latter node.In addition, the framework also uses a hash table to achieve fast search operations. 2. Data reading: When you need to read the data in the cache, first find the corresponding node in the hash table.If the node exists, it means that the data has been relieved on the hard disk, you can read directly from the hard disk and move the node to the head of the linked list.This is to ensure that the recently used data is always located at the head of the linked list to increase the speed of subsequent access.If the node does not exist, you need to obtain the data from the data source, and write the data into the hard disk and cache. 3. Data writing: When you need to write data to the cache, first check whether the current size of the cache has reached the maximum capacity.If you exceed the maximum capacity, you need to remove the longest unused data to free up the space.Then add the new data to the head of the linked list and create a corresponding node in the hash table.Finally, the data is written into the hard disk and cache. 4. Cache elimination strategy: "Disk Lru Cache" uses the LRU algorithm to decide which data to eliminate.When the cache capacity reaches the maximum value, the node at the rear of the linked list will be removed, that is, the longest data that has not been used.This can ensure that the recently used data is always stored in the cache, thereby improving the performance of data access. Complete code and related configuration: Below is a Java code example using the "Disk Lru Cache" framework: Cache<String, String> cache = new Cache<>(capacity, directory, appVersion, maxSize); String key = "example_key"; String value = "example_value"; // Write the data to the cache cache.put(key, value); // Read data from the cache String retrievedValue = cache.get(key); if (retrievedValue != null) { System.out.println("Retrieved value: " + retrievedValue); } // Empty the cache cache.clear(); In the above code, the "Cache" class is the main class provided by the "Disk Lru Cache" framework to create and manage cache.When creating the "Cache" object, the capacity, directory, application version and maximum cache size need to be specified.You can then use the "PUT" method to write the data to the cache and use the "Get" method to read the data from the cache.Finally, the "Clear" method can be used to clear the entire cache. To use the "Disk Lru Cache" framework, you need to add related configurations.For example, in Gradle, the following dependencies can be added: groovy dependencies { implementation 'com.jakewharton:disklrucache:2.0.2' } By adding the above -mentioned dependencies, you can integrate the "Disk Lru Cache" framework into the Java project and use the functions provided to achieve data cache. Summarize: The "Disk Lru Cache" framework is a Java class library for caching data that stores data to the hard disk to save memory and improve system performance.By using the LRU algorithm to manage the data in the cache, it ensures that the recently used data is always retained in the cache.By understanding the technical principles and use examples of the "Disk Lru Cache" framework, we can better apply it to optimize our Java application.