设置Redis Java: Setting Expiration Time.（redisjava过期）

Redis Java is an open source database which provides users with a fast and reliable way to store data. It provides different kinds of data structures for different types of data and helps users to easily store and manipulate data without needing to write a lot of code. Redis also has a feature that allows users to set an expiration time for certain data.

Setting an expiration time for certain data in Redis Java can be done using the Jedis API. Jedis is a Redis client for Java. It provides a simple API for remote access to Redis. To set an expiration time for a key in Redis Java, users can use the `expire` method. This method takes a key and a number of seconds as its parameters and set the expiration time of the key to the number of seconds specified.

For example, if a user wants to set the expiration time of a key to five seconds, they can use the following code:

“`Java

Jedis jedis = new Jedis(“redis-server-ip”, 6379);

jedis.expire(“key”, 5);

In this example, the key is expired in five seconds. The expiration time for a key can also be set to a Unix timestamp. To do this, the `expireAt` method can be used. This method takes a key and an epoch time as its parameters and set the expiration time of the key to the epoch time specified.

For example, if a user wants to set the expiration time of a key to 19th May 2021, they can use the following code:

```Java
Jedis jedis = new Jedis("redis-server-ip", 6379);
jedis.expireAt("key", 1621529600000);

In this example, 1621529600000 is the epoch time corresponding to 19th May 2021 and the key is expired on that date.

Users can also set an expiration time for an entire hash. The `hset` method in Jedis can be used for this. This method takes the name of the hash and a key-value pair as its parameters and set the expiration time for the key in the hash. The expiration time for the key can be specified using a number of seconds or epoch time.

By using the Jedis API, Redis Java users can easily set an expiration time for a key or an entire hash. Setting an expiration time can help users to make sure that their data is not stored unnecessarily and minimize the system’s resource usage.