不会删Redis Java: Expiry Not Deletion（redisjava过期）

Redis Java: Expiry Not Deletion

Redis is an in-memory data store that has many applications and uses, including as a database, message broker, and caching service. It supports a wide range of data structures such as strings, hashes, lists, sets, and so on. Redis supports data types and expiring fields. It’s often used to store key-value pairs with an expiration time, allowing developers to quickly access data while keeping it up-to-date.

When using Redis with the Java programming language, it is possible to implement the expiration of keys. However, most developers do not do this for multiple reasons – it takes more time, is more complex and generally more difficult to debug. In many cases, it is simpler to use a library that implements the expiry directly – such as Jedis, Redisson or Lettuce.

When using these libraries, it is possible to remove certain keys from the database according to an expiration time. For example, using Jedis you could use setex() which sets the expiration time for a key:

jedis.setex("foo", 600, "bar");

This sets the expiration time in seconds. When dealing with expirable key-value pairs, it is also possible to chain other methods. For example, a basic key-value pair can be easily fetched and revived:

String resultValue = jedis.get("foo");
jedis.expire("foo", 1000);

In other cases, you may wish to delete a certain key from Redis. While you can use the expire() to invalidate keys, you should never use the del() command to delete keys. This is because del() is a time-complex command – it is much faster to use expire() instead.

In summary, Redis Java can be used to expire keys in order to keep data up-to-date. Developers should avoid using the del() command, as this is an expensive operation. Instead, they should opt for methods such as setex() or expire() which are far more efficient. By utilizing these methods, developers can ensure that their Java applications perform optimally when dealing with time-sensitive data.