Learn about Ehcache 3 caching technology

Ehcache 3 is a very popular Java caching technology that improves application performance and responsiveness. In this article, we will introduce how Ehcache 3 works and features, and how to use Ehcache 3 to build an efficient caching system.

1. Introduction to Ehcache 3

Ehcache 3 is a memory-based caching library that provides two modes: distributed caching and local caching. It supports distributed and high-availability architectures and integrates well into the Spring framework.

Ehcache 3 is written in Java, which provides an easy-to-use API that makes it easy for developers to integrate Ehcache 3 into their applications. Ehcache 3 also supports cache size control, as well as cache sharing among multiple applications.

2. The working principle of Ehcache 3

The working principle of Ehcache 3 is very simple. It uses the Map interface to store key-value pairs. When a value is added to Ehcache, it first checks if there is enough space in memory to store the value. If there is not enough space, Ehcache 3 will try to write some cache entries to disk to free up memory space before the new value can be stored in memory.

When data is stored in Ehcache 3, it automatically adds a timestamp. This timestamp can be used to determine the age of the cache entry. When a cache entry expires, it is automatically removed from the cache.

Ehcache 3 also supports cache warm-up. Warming cache means loading cache data when the application starts, which can improve the performance and responsiveness of the application.

3. Functions of Ehcache 3

1. Support distributed cache

Ehcache 3 supports distributed cache and can store data on multiple nodes . This improves application performance and scalability because multiple nodes can share the cache. In addition, distributed caching also improves cache availability because even if one of the nodes fails, the other nodes can still provide services.

2. Support local cache

In addition to distributed cache, Ehcache 3 also supports local cache. Local cache is stored only in a single JVM and can provide a lightweight caching solution. In some cases, a local cache can be more suitable than a distributed cache.

3. Support cache management

Ehcache 3 supports cache management, and the cache can be queried and managed through JMX or REST API. These management functions include exporting the cache, monitoring the cache, clearing the cache, and reloading the cache.

4. Cache-enabled storage

Ehcache 3 provides a variety of cache storage options, including Heap, Off-Heap, and Disk. Heap storage stores cache data in the JVM heap, Off-Heap storage stores cache data in memory outside the JVM, and Disk storage stores cache data on disk. These storage options can be selected based on data size and performance needs.

4. Using Ehcache 3

Before using Ehcache 3, you must first add the dependency of Ehcache 3 to the project. You can use Maven to manage dependencies. Add the following dependencies in pom.xml:

<dependency>
      <groupId>org.ehcache</groupId>
      <artifactId>ehcache</artifactId>
      <version>3.x.x</version>
</dependency>

After adding the Ehcache 3 dependencies, you are ready to start using Ehcache 3. The following is a simple example that shows how to use Ehcache 3 to create a local cache, add data, and read the data by key:

CacheManager cacheManager = CacheManagerBuilder.newCacheManagerBuilder().build(true);

Cache<String, String> myCache = cacheManager.createCache("myCache",
    CacheConfigurationBuilder.newCacheConfigurationBuilder(String.class, String.class,
        ResourcePoolsBuilder.heap(10)));

myCache.put("key1", "value1");
String value1 = myCache.get("key1");

In this example, we create a local cache named "myCache" Cache, size 10. We then added a "key1" and "value1" pair to the cache and got the value by key "key1". When the cache size exceeds 10 entries, the oldest entries are automatically deleted based on the LRU algorithm.

5. Summary

Ehcache 3 is a powerful caching technology. It provides two modes: distributed caching and local caching, and supports cache size control, cache preheating, and caching. Features such as storage options and cache management. It is easy to use and integrates well with the Spring framework. If you are looking for a caching technology that can improve application performance and responsiveness, then Ehcache 3 is a good choice.

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