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

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.

Answer 2

try:
Set<byte[]> keys = RedisTemplate.getConnectionFactory().getConnection().keys("*".getBytes());
Iterator<byte[]> it = keys.iterator();
while(it.hasNext()){
byte[] data = (byte[])it.next();
System.out.println(new String(data, 0, data.length));
}

Answer 3

Try redisTemplate.setKeySerializer(new StringRedisSerializer());

Answer 4

Avoid to use keys command. It may ruin performance when it is executed against large databases.
You should use scan command instead. Here is how you can do it:
RedisConnection redisConnection = null;
try {
redisConnection = redisTemplate.getConnectionFactory().getConnection();
ScanOptions options = ScanOptions.scanOptions().match("myKey*").count(100).build();
Cursor c = redisConnection.scan(options);
while (c.hasNext()) {
logger.info(new String((byte[]) c.next()));
}
} finally {
redisConnection.close(); //Ensure closing this connection.
}
or do it much simplier with Redisson Redis Java client:
Iterable<String> keysIterator = redisson.getKeys().getKeysByPattern("test*", 100);
for (String key : keysIterator) {
logger.info(key);
}

Answer 5

Try
import org.springframework.data.redis.core.RedisTemplate;
import org.apache.commons.collections.CollectionUtils;
String key = "example*";
Set keys = redisTemplate.keys(key);
if (CollectionUtils.isEmpty(keys)) return null;
List list = redisTemplate.opsForValue().multiGet(keys);

Answer 6

It did work, but seems not recommended? Because we can't use Keys command in production. I assume RedisTemplate.getConnectionFactory().getConnection().keys is calling redis Keys command. What are the alternatives?

Answer 7

I was using redisTemplate.keys(), but it was not working. So I used jedis, it worked. The following is the code that I used.
Jedis jedis = new Jedis("localhost", 6379);
Set<String> keys = jedis.keys("*".getBytes());
for (String key : keys) {
// do something
} // for

Answer 8

Solution can be like this
String pattern = "abc"+"*";
Set<String> keys = jedis.keys(pattern);
for (String key : keys) {
jedis.keys(key);
}
Or you can use jedis.hscan() and ScanParams instead.