Cache clearing mechanism in Java caching technology

Java caching technology is an important means to improve system performance and optimize user experience. The caching mechanism is a commonly used method, which can improve the access speed and resource utilization efficiency of the system. However, as the usage time increases, more and more data will be stored in the cache. The cache clearing mechanism is an important method to solve this problem. This article will introduce the cache clearing mechanism in Java cache technology, including common cache clearing strategies and clearing methods.

1. Common cache clearing strategies

1. Time expiration strategy

When data is cached, an aging period is added to each data. When the data has passed the aging period, The data will then be automatically removed. This strategy is a common clearing strategy that can effectively avoid the impact of expired data on cache performance. Time expiration policy can be implemented using TTL (Time-To-Live). TTL means that cached data should be kept alive within a certain period of time. When the preset time is reached, the cached data will be cleared.

2. Memory capacity strategy

Set a memory capacity upper limit for the cache. When the cached data in the memory gradually increases and the memory occupied exceeds the preset memory capacity upper limit, the system will start Do a cache clear.

3. Data operation strategy

The data operation strategy refers to selecting the priority of clearing data based on the type of cached data, access frequency and other characteristics. This strategy can ensure that the cache of critical data will not be cleared, and system performance will not be greatly affected after data with low access frequency is cleared.

4. Elimination algorithm strategy

The cache capacity is limited. When the cache is almost full, the system must decide on its own what data needs to be cleared to make room. At this time, the elimination algorithm can effectively solve this problem. The elimination algorithm refers to selecting a strategy for clearing data based on characteristics such as frequency of use and time sequence of cached data. Common elimination algorithms include LRU (least recently used), FIFO (first in first out), LFU (least frequently used), etc.

2. Common clearing methods

1. Manual clearing

Manual clearing means that developers actively call the clearing method to clear cached data when writing code. Manual removal is the most basic removal method, but it is also one of the most effective.

2. Regular clearing

Periodic clearing refers to clearing cache data regularly according to the cache clearing policy. This method can prevent the cache from becoming too large and ensure system performance and stability.

3. Insufficient memory clearing

When the system memory reaches the preset upper limit, the system will automatically clear the cache. This method can effectively prevent system crashes.

4. Load balancing clearing

When the system is running on multiple servers, a load balancing strategy can be used to balance cache pressure. When the load on a certain server is too high and the cache reaches a certain size, the cache on it can be cleared to reduce server pressure.

Conclusion:

Java cache technology is an effective means to improve system performance, and the cache clearing mechanism is an important method to ensure cache usage efficiency and stability. Cache clearing requires formulating cache clearing strategies and methods based on specific circumstances, and constantly improving and updating the cache clearing mechanism to meet the needs of efficient and stable operation of the system.

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