Springboot+Vue+SSE+Redis

Question

提示RedisCache没有incr、decr等方法，请问是需要自己添加吗？

Answer 1

是的，Spring Boot默认的RedisCache并没有实现incr、decr等方法。您需要实现一个自定义的缓存管理器来扩展RedisCache的功能。

以下是一些实现incr和decr的示例代码：

import org.springframework.cache.Cache;
import org.springframework.cache.support.SimpleValueWrapper;
import org.springframework.data.redis.cache.RedisCache;
import org.springframework.data.redis.core.RedisOperations;

public class CustomRedisCache extends RedisCache {
    private final RedisOperations redisOperations;

    public CustomRedisCache(String name, byte[] prefix, RedisOperations<? extends Object, ? extends Object> redisOperations, long expiration) {
        super(name, prefix, redisOperations, expiration);
        this.redisOperations = redisOperations;
    }

    @Override
    public ValueWrapper get(Object key) {
        ValueWrapper wrapper = super.get(key);
        if (wrapper != null && wrapper.get() != null) {
            return new SimpleValueWrapper(Integer.valueOf(wrapper.get().toString()));
        }
        return wrapper;
    }

    @Override
    public void put(Object key, Object value) {
        redisOperations.opsForValue().increment(key.toString(), (long) value);
        super.put(key, value);
    }

    public void decrement(Object key) {
        redisOperations.opsForValue().decrement(key.toString());
    }

    public long getLong(Object key) {
        Long value = redisOperations.opsForValue().increment(key.toString(), 0L);
        return (value != null ? value : 0L);
    }
}

这个自定义缓存管理器扩展了RedisCache，并添加了一个名为decrement的新方法。同时，在get和put方法中，它将缓存中的值转换为整数。

在您的Spring Boot应用程序中，您可以通过将CustomRedisCache作为缓存管理器来使用它：

@Configuration
@EnableCaching
public class CacheConfig extends CachingConfigurerSupport {
    @Autowired
    private RedisConnectionFactory redisConnectionFactory;

    @Bean
    @Override
    public CacheManager cacheManager() {
        RedisCacheManager redisCacheManager = new RedisCacheManager(redisTemplate());
        redisCacheManager.setDefaultExpiration(3600);
        redisCacheManager.setUsePrefix(true);

        CustomRedisCache customRedisCache = new CustomRedisCache("customCache", "customCache:".getBytes(), redisTemplate(), 3600);
        Map<String, RedisCacheConfiguration> cacheConfigurations = new HashMap<>();
        cacheConfigurations.put("customCache", RedisCacheConfiguration.defaultCacheConfig().entryTtl(Duration.ofHours(1)));
        redisCacheManager.setCacheConfigurations(cacheConfigurations);
        redisCacheManager.setCaches(Arrays.asList(customRedisCache));
        return redisCacheManager;
    }

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

```
这里的CustomRedisCache被添加到了RedisCacheManager中，而其他的默认RedisCache使用RedisCacheConfiguration设置缓存时间。这样，您就可以使用自定义的缓存管理器来实现incr和decr方法。