Setting Expire Time - EX EXAT PX PXAT and KEEPTTL with Spring Boot + Redis

If you would have worked with the Redis command, you must be familiar with the below SET options that you can use to set expiration or TTL for a key.

Option	:	What it does?
EX	:	Sets expiration time in seconds.
EXAT	:	Sets the Unix time at which the key will expire in seconds.
PX	:	Sets expiration time in milliseconds.
PXAT	:	Sets the Unix time at which the key will expire in milliseconds.
KEEPTTL	:	Retain the TTL value associated with the key.

Let us see examples of each of the with Spring Boot.

EX: Setting expiration time in seconds

   @Autowired
    private RedisTemplate redisTemplate;

    private long expirationTimeInSeconds = 1;

    public void setKeyWithEx() throws InterruptedException {
        redisTemplate.opsForValue().set("city", "New York", Duration.ofSeconds(expirationTimeInSeconds));
        Thread.sleep(3000);
        System.out.println(redisTemplate.opsForValue().get("message"));
    }

As we have set the EX duration of 1 second and have added a thread sleep of 3 seconds we get a null response as the key got deleted before retrieval.

EXAT: Setting the Unix time at which the key will expire in seconds.

    public void setKeyWithEXAT() {
        Instant instant = Instant.ofEpochSecond(expirationTimeInSeconds);
        redisTemplate.opsForValue().set("city", "New York", Duration.between(Instant.now(),instant));
    }

PX: Setting expiration time in milliseconds

   @Autowired
    private RedisTemplate redisTemplate;

    private long expirationTimeInMilliSeconds = 1;

    public void setKeyWithPX()  {
        redisTemplate.opsForValue().set("city", "New York", Duration.ofMillis(expirationTimeInMilliSeconds));
    }

PXAT: Setting the Unix time at which the key will expire in milliseconds.

    public void setKeyWithPXAT() {
        Instant instant = Instant.ofEpochMilli(expirationTimeInMilliSeconds);
        redisTemplate.opsForValue().set("city", "New York", Duration.between(Instant.now(),instant));
    }

PXAT: we want to preserve the existing time-to-live (TTL) value of a key.

@Autowired
private StringRedisTemplate redisTemplate;

public void setKeepTtlValue() {
    redisTemplate.execute(connection -> {
        byte[] keyBytes = redisTemplate.getKeySerializer().serialize("city");
        byte[] valueBytes = redisTemplate.getValueSerializer().serialize("Chicago"); //setting a new value
        Boolean result = connection.set(keyBytes, valueBytes, Expiration.KEEP_TTL, RedisStringCommands.SetOption.UPSERT);
        System.out.println(result);
    });
}

You should get a result as a boolean true.