spring-data-redis redisTemplate Exception

Question

When I call get() method, an exception occured

here is the code

@Service("RedisService")
public class RedisServiceImpl implements RedisService {

@Autowired
RedisTemplate<String, Long> redisTemplate;

@Override
public Long get(String key) {
    return redisTemplate.opsForValue().get(key);
}

@Override
public Long incrBy(String key, long increment) {
    return redisTemplate.opsForValue().increment(key, increment);
}

when I use incrBy method, there are no exceptions but only errors only get method





here is the stacktrace ---

java.io.EOFException
    at java.io.ObjectInputStream$PeekInputStream.readFully(ObjectInputStream.java:2280)
    at java.io.ObjectInputStream$BlockDataInputStream.readShort(ObjectInputStream.java:2749)
    at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:779)
    at java.io.ObjectInputStream.<init>(ObjectInputStream.java:279)
    at org.springframework.core.serializer.DefaultDeserializer.deserialize(DefaultDeserializer.java:38)
    at org.springframework.core.serializer.support.DeserializingConverter.convert(DeserializingConverter.java:58)
    at org.springframework.core.serializer.support.DeserializingConverter.convert(DeserializingConverter.java:1)
    at org.springframework.data.redis.serializer.JdkSerializationRedisSerializer.deserialize(JdkSerializationRedisSerializer.java:40)
    at org.springframework.data.redis.core.AbstractOperations.deserializeValue(AbstractOperations.java:198)
    at org.springframework.data.redis.core.AbstractOperations$ValueDeserializingRedisCallback.doInRedis(AbstractOperations.java:50)
    at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:162)
    at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:133)
    at org.springframework.data.redis.core.AbstractOperations.execute(AbstractOperations.java:84)
    at org.springframework.data.redis.core.DefaultValueOperations.get(DefaultValueOperations.java:42)
    at net.daum.air21.bot.common.service.RedisServiceImpl.get(RedisServiceImpl.java:29)
    at net.daum.air21.bot.user.service.SeraCoffeeServiceImpl.getCurrentCount(SeraCoffeeServiceImpl.java:41)

Answer 1

By default, RedisTemplate uses a JdkSerializationRedisSerializer, so if you did a "set" it would make your Long look something like this in Redis:

"\xac\xed\x00\x05sr\x00\x0ejava.lang.Long;\x8b\xe4\x90\xcc\x8f#\xdf\x02\x00\x01J\x00\x05valuexr\x00\x10java.lang.Number\x86\xac\x95\x1d\x0b\x94\xe0\x8b\x02\x00\x00xp\x00\x00\x00\x00\x00\x00\x00\x04"

IncrBy works because Redis always returns a Long from that operation, so RedisTemplate does not attempt to deserialize the result. The result of "get", however, goes through the deserialization process, which expects a format like the above.

You can solve this by using a different value serializer on your RedisTemplate:

redisTemplate.setValueSerializer(new GenericToStringSerializer<Long>(Long.class));

Or try the RedisAtomicLong class that comes with spring-data-redis.

Answer 2

Bit frustrating - thanks for the tip on RedisAtomicLong.. but here is a solution for using HashOps with String Key, String field and Long value - uses Spring Boot for ease of configuration

@SpringBootApplication
@Configuration
public class DemoApplication {

    public static void main(String[] args) {
        final ConfigurableApplicationContext context = SpringApplication.run(DemoApplication.class, args);
        final DacRepository dacRepository  = context.getBean(DacRepository.class);
        dacRepository.incrKeyExample();
    }


    @Bean
    public RedisTemplate<String, Long> getLongRedisTemplate(RedisConnectionFactory redisConnectionFactory) {
         final RedisTemplate<String,Long> redisTemplate = new RedisTemplate<String, Long>();
         redisTemplate.setConnectionFactory(redisConnectionFactory);
         redisTemplate.setHashValueSerializer(new GenericToStringSerializer<Long>(Long.class));
         redisTemplate.setKeySerializer(new StringRedisSerializer());
         redisTemplate.setValueSerializer(new GenericToStringSerializer<Long>(Long.class));
         redisTemplate.setHashKeySerializer(new StringRedisSerializer());
         redisTemplate.afterPropertiesSet();
         return redisTemplate;
    }
}

import java.util.Set;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.HashOperations;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Repository;

@Repository

public class DacRepository {

    private final HashOperations<String, String, Long> hashOps;

    @Autowired
    private final RedisTemplate<String, Long> redisTemplate;

    @Autowired
    public DacRepository(RedisTemplate<String, Long> redisTemplate) {
        this.redisTemplate = redisTemplate;
        hashOps = redisTemplate.opsForHash();

    }


    public void incrKeyExample() {
        final Set<String> keys = this.redisTemplate.keys("*");
        for(String key: keys) {
            System.out.println("key: "+ key);
        }

        final String key = "deal-1";
        final String field = "view";
        final Long value = 1L;
        hashOps.put(key, field, value);
        final Long delta = 1L;
        hashOps.increment(key, field, delta);
        Long val = hashOps.get("deal-1", "view");
        System.out.println("Value = "+val);
    }

}




server.port=9001
spring.redis.host=localhost
spring.redis.port=6379
spring.redis.pool.max-idle=8
spring.redis.pool.min-idle=0
spring.redis.pool.max-active=8
spring.redis.pool.max-wait=-1