默认情况下，SpringBoot中配置的Redis序列化器为JdkSerializationRedisSerializer，这一点我们可以从SpringBoot的默认配置代码中查看获得：

同步模式的AutoConfiguration

@Configuration
@ConditionalOnClass(RedisOperations.class)
@EnableConfigurationProperties(RedisProperties.class)
@Import({ LettuceConnectionConfiguration.class, JedisConnectionConfiguration.class })
public class RedisAutoConfiguration {

    @Bean
    @ConditionalOnMissingBean(name = "redisTemplate")
    public RedisTemplate<Object, Object> redisTemplate(
            RedisConnectionFactory redisConnectionFactory) throws UnknownHostException {
        RedisTemplate<Object, Object> template = new RedisTemplate<>();
        template.setConnectionFactory(redisConnectionFactory);
        return template;
    }

    @Bean
    @ConditionalOnMissingBean
    public StringRedisTemplate stringRedisTemplate(
            RedisConnectionFactory redisConnectionFactory) throws UnknownHostException {
        StringRedisTemplate template = new StringRedisTemplate();
        template.setConnectionFactory(redisConnectionFactory);
        return template;
    }

}

Reactive模式的AutoConfiguration

@Configuration
@ConditionalOnClass({ ReactiveRedisConnectionFactory.class, ReactiveRedisTemplate.class,
        Flux.class })
@AutoConfigureAfter(RedisAutoConfiguration.class)
public class RedisReactiveAutoConfiguration {

    @Bean
    @ConditionalOnMissingBean(name = "reactiveRedisTemplate")
    @ConditionalOnBean(ReactiveRedisConnectionFactory.class)
    public ReactiveRedisTemplate<Object, Object> reactiveRedisTemplate(
            ReactiveRedisConnectionFactory reactiveRedisConnectionFactory,
            ResourceLoader resourceLoader) {
        JdkSerializationRedisSerializer jdkSerializer = new JdkSerializationRedisSerializer(
                resourceLoader.getClassLoader());
        RedisSerializationContext<Object, Object> serializationContext = RedisSerializationContext
                .newSerializationContext().key(jdkSerializer).value(jdkSerializer)
                .hashKey(jdkSerializer).hashValue(jdkSerializer).build();
        return new ReactiveRedisTemplate<>(reactiveRedisConnectionFactory,
                serializationContext);
    }

}

JdkSerializationRedisSerializer的特点是在Redis中Key的值会带一个前缀，一般如下：

127.0.0.1:6379> keys *
1) "\xac\xed\x00\x05t\x00\nJwKjKWCTmf"

这个前缀在一些查询工具中会以乱码的形式展现，自然也没法用查询工具查的其中的值。因此，我们需要做默认的配置做一些变更。

其实SpringBoot已经提供了一个String方式序列化的模板，就如上面所示的配置

    @Bean
    @ConditionalOnMissingBean
    public StringRedisTemplate stringRedisTemplate(
            RedisConnectionFactory redisConnectionFactory) throws UnknownHostException {
        StringRedisTemplate template = new StringRedisTemplate();
        template.setConnectionFactory(redisConnectionFactory);
        return template;
    }

不过如果我们只需要Key进行String序列化，Value进行不同方式的序列化，那么我们可以覆盖这个默认配置，如下：

@Configuration
public class RedisConfig {

    // Reactive 模板
    @Bean(name = "reactiveRedisTemplate")
    public ReactiveRedisTemplate<String, Object> reactiveRedisTemplate(
            ReactiveRedisConnectionFactory reactiveRedisConnectionFactory) {

        RedisSerializationContext<String, Object> serializationContext = RedisSerializationContext.<String, Object>
            newSerializationContext()
                .key(new StringRedisSerializer())
                .value(new GenericJackson2JsonRedisSerializer()) // GenericJackson2JsonRedisSerializer
                .hashKey(new StringRedisSerializer())
                .hashValue(new GenericJackson2JsonRedisSerializer()) // GenericJackson2JsonRedisSerializer
            .build();

        return new ReactiveRedisTemplate<>(reactiveRedisConnectionFactory, serializationContext);
    }

    // 同步模板
    @Bean(name = "redisTemplate")
    public RedisTemplate<String, Object> redisTemplate(@Autowired RedisConnectionFactory factory) {
        RedisTemplate<String, Object> template = new RedisTemplate<>();
        template.setConnectionFactory(factory);
        template.setKeySerializer(new StringRedisSerializer());
        template.setHashKeySerializer(new StringRedisSerializer()); // GenericJackson2JsonRedisSerializer
        template.setValueSerializer(new GenericJackson2JsonRedisSerializer());
        template.setHashValueSerializer(new GenericJackson2JsonRedisSerializer()); // GenericJackson2JsonRedisSerializer
        template.setEnableTransactionSupport(true);
        return template;
    }

}