Introduction to caching applications in Java language

Java is a widely used programming language. It not only has huge advantages in developing web applications, mobile applications, and desktop applications, but also has unique advantages in caching processing. In Java, caching technology is a very practical technology designed to speed up the response speed of applications. In this article, we will focus on caching applications in the Java language.

1. What is cache?

First of all, we need to clarify what cache is. Cache is a type of high-speed memory used to store frequently accessed data in memory to reduce access to slow disk memory. In Java, caching technology refers to storing certain data in memory and quickly reading the data when needed to improve the response speed of the application.

2. Common caching technologies

2.1. Memory caching

Memory caching refers to caching data into memory to improve the response speed of the application . In Java, HashMap and ConcurrentHashMap in the Java Collection framework are mainly used to implement memory caching. Both classes are implemented based on hash tables and have the characteristics of fast search and insertion.

2.2. Guava Cache

Guava is a commonly used caching framework open sourced by Google. The Cache interface provides a simple caching mechanism. In Guava, we can optimize cache performance by setting the maximum size of the cache, expiration time, loading method of cache entries, etc.

2.3. Redis Cache

Redis is an open source, high-performance memory data storage system that can not only be used as a database, but also can be used to implement efficient caching. In Java, we can improve the performance of our application by using Redis caching technology. Of course, in the process of using Redis, you need to pay attention to issues such as Redis selection, custom serialization, data backup, and data type support.

3. How to use caching

In Java, using caching technology can improve system performance, but you need to pay attention to the following points:

3.1. Caching Cleanup

When the data in the cache expires or is too large, the cache needs to be cleared in time. In Java, we can use the expireAfterWrite and maximumSize methods in Guava's CacheBuilder class to set the cache expiration time and the maximum size of the cache to achieve the purpose of regularly cleaning the cache.

3.2. Avoid cache avalanche

When the data in the cache expires or becomes invalid at the same time, it may cause a large number of requests to fall into the database or other systems, causing the system to crash. To avoid this situation, a variety of caching mechanisms can be used, such as random delays, distributed caching, cache refresh mechanisms, etc.

3.3. Cache penetration

When using cache, you may encounter cache penetration problems. Cache penetration refers to querying data that does not exist, and this data does not exist every time. This will cause a large number of invalid requests to penetrate the cache and fall into the background system, thus affecting the performance of the system. To avoid this, you can use Bloom filters, cache null values, or use hotspot data queries to mitigate the impact of cache penetration.

4. Summary

Caching technology in the Java language plays an important role in improving system performance. When using cache, you need to pay attention to cache cleaning, avoiding cache avalanches, cache penetration and other issues, so that the cache technology can play its maximum role. At the same time, when choosing the appropriate caching technology, you also need to make trade-offs based on application scenarios, system requirements and other factors.

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