请在springboot里面配置一个redis来缓存一个以 Token 为 Key，用户信息为 Value

可以在 Spring Boot 中使用以下代码配置 Redis 缓存：

1. 添加 Redis 依赖：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

2. 在 application.properties 文件中配置 Redis：

# Redis 配置
spring.redis.host=127.0.0.1
spring.redis.port=6379
spring.redis.password=
spring.redis.database=0

3. 创建 Redis 配置类：

@Configuration
@EnableCaching
public class RedisConfig extends CachingConfigurerSupport {

    @Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) {
        RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
        redisTemplate.setConnectionFactory(redisConnectionFactory);
        redisTemplate.setKeySerializer(new StringRedisSerializer());
        redisTemplate.setValueSerializer(new GenericJackson2JsonRedisSerializer());
        return redisTemplate;
    }

    @Bean
    public CacheManager cacheManager(RedisConnectionFactory redisConnectionFactory) {
        RedisCacheConfiguration redisCacheConfiguration = RedisCacheConfiguration.defaultCacheConfig()
                .entryTtl(Duration.ofMinutes(30))
                .disableCachingNullValues()
                .serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(new StringRedisSerializer()))
                .serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(new GenericJackson2JsonRedisSerializer()));
        return RedisCacheManager.builder(redisConnectionFactory)
                .cacheDefaults(redisCacheConfiguration)
                .build();
    }
}

4. 在需要缓存的方法上添加 @Cacheable 注解：

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserRepository userRepository;

    @Autowired
    private RedisTemplate<String, Object> redisTemplate;

    @Override
    @Cacheable(value = "user", key = "#token")
    public User getUserByToken(String token) {
        User user = (User) redisTemplate.opsForValue().get(token);
        if (user == null) {
            user = userRepository.findByToken(token);
            redisTemplate.opsForValue().set(token, user);
        }
        return user;
    }
}

以上代码将以 Token 为 Key，用户信息为 Value 进行缓存。