spring - How to get all Keys from Redis using redis template

Question

I have been stuck with this problem with quite some time.I want to get keys from redis using redis template. I tried this.redistemplate.keys("*"); but this doesn't fetch anything. Even with the pattern it doesn't work.

Can you please advise on what is the best solution to this.

Answer 1

I just consolidated the answers, we have seen here.

Here are the two ways of getting keys from Redis, when we use RedisTemplate.

1. Directly from RedisTemplate

Set<String> redisKeys = template.keys("samplekey*"));
// Store the keys in a List
List<String> keysList = new ArrayList<>();
Iterator<String> it = redisKeys.iterator();
while (it.hasNext()) {
       String data = it.next();
       keysList.add(data);
}

Note: You should have configured redisTemplate with StringRedisSerializer in your bean

If you use java based bean configuration

redisTemplate.setDefaultSerializer(new StringRedisSerializer());

If you use spring.xml based bean configuration

<bean id="stringRedisSerializer" class="org.springframework.data.redis.serializer.StringRedisSerializer"/>

<!-- redis template definition -->
<bean
    id="redisTemplate"
    class="org.springframework.data.redis.core.RedisTemplate"
    p:connection-factory-ref="jedisConnectionFactory"
    p:keySerializer-ref="stringRedisSerializer"
    />

2. From JedisConnectionFactory

RedisConnection redisConnection = template.getConnectionFactory().getConnection();
Set<byte[]> redisKeys = redisConnection.keys("samplekey*".getBytes());
List<String> keysList = new ArrayList<>();
Iterator<byte[]> it = redisKeys.iterator();
while (it.hasNext()) {
       byte[] data = (byte[]) it.next();
       keysList.add(new String(data, 0, data.length));
}
redisConnection.close();

If you don't close this connection explicitly, you will run into an exhaustion of the underlying jedis connection pool as said in https://stackoverflow.com/a/36641934/3884173.