【Redis】 Redis如何缓存数据

矫情吗；* 2023-10-04 23:01 2阅读 0赞

## Redis如何缓存数据 ##

#### 目录 ####

*  Redis如何缓存数据
 *   *  步骤
     *   *  先取缓存再存缓存
         *  RedisCache类
         *  SpringUtils类
         *  启动类加上注解

### 步骤 ###

#### 先取缓存再存缓存 ####

判断key是否存在，如果存在，直接取缓存的值 ，不存在就从数据库查出数据，并把值存到redis里。  
案例：

@Override
        public List<GoodsCategoryTree> selectTree(GoodsCategory goodsCategory) {
        
        //取缓存
    		if(redisTemplate.hasKey(CacheConstants.GOODS_CATEGORY_TREE_KEY)){
        
    			log.info("商品类目管理 selectTree cache");
    			List<GoodsCategoryTree> cacheList = SpringUtils.getBean(RedisCache.class).getCacheList(CacheConstants.GOODS_CATEGORY_TREE_KEY);
    			return cacheList;
    		}
    		log.info("商品类目管理 selectTree db");
    		List<GoodsCategoryTree> treeList = getTree(this.list(Wrappers.lambdaQuery(goodsCategory)));
    		if (CollUtil.isNotEmpty(treeList)){
        
    		//存缓存
    			SpringUtils.getBean(RedisCache.class).setCacheList(CacheConstants.GOODS_CATEGORY_TREE_KEY,treeList);
    		}
            return treeList;
        }

其中

#### RedisCache类 ####

/**
     * @Description: spring redis 工具类
     */
    @SuppressWarnings(value = {
        "unchecked", "rawtypes"})
    @Component
    public class RedisCache {
        
        @Autowired
        public RedisTemplate redisTemplate;
    
        /**
         * 缓存基本的对象，Integer、String、实体类等
         *
         * @param key   缓存的键值
         * @param value 缓存的值
         * @return 缓存的对象
         */
        public <T> ValueOperations<String, T> setCacheObject(String key, T value) {
        
            ValueOperations<String, T> operation = redisTemplate.opsForValue();
            operation.set(key, value);
            return operation;
        }
    
        /**
         * 缓存基本的对象，Integer、String、实体类等
         *
         * @param key      缓存的键值
         * @param value    缓存的值
         * @param timeout  时间
         * @param timeUnit 时间颗粒度
         * @return 缓存的对象
         */
        public <T> ValueOperations<String, T> setCacheObject(String key, T value, Integer timeout, TimeUnit timeUnit) {
        
            ValueOperations<String, T> operation = redisTemplate.opsForValue();
            operation.set(key, value, timeout, timeUnit);
            return operation;
        }
    
        /**
         * 获得缓存的基本对象。
         *
         * @param key 缓存键值
         * @return 缓存键值对应的数据
         */
        public <T> T getCacheObject(String key) {
        
            ValueOperations<String, T> operation = redisTemplate.opsForValue();
            return operation.get(key);
        }
    
        /**
         * 删除单个对象
         *
         * @param key
         */
        public void deleteObject(String key) {
        
            redisTemplate.delete(key);
        }
    
        /**
         * 删除集合对象
         *
         * @param collection
         */
        public void deleteObject(Collection collection) {
        
            redisTemplate.delete(collection);
        }
    
        /**
         * 缓存List数据
         *
         * @param key      缓存的键值
         * @param dataList 待缓存的List数据
         * @return 缓存的对象
         */
        public <T> ListOperations<String, T> setCacheList(String key, List<T> dataList) {
        
            ListOperations listOperation = redisTemplate.opsForList();
            if (null != dataList) {
        
                int size = dataList.size();
                for (int i = 0; i < size; i++) {
        
                    listOperation.leftPush(key, dataList.get(i));
                }
            }
            return listOperation;
        }
    
        /**
         * 获得缓存的list对象
         *
         * @param key 缓存的键值
         * @return 缓存键值对应的数据
         */
        public <T> List<T> getCacheList(String key) {
        
            List<T> dataList = new ArrayList<T>();
            ListOperations<String, T> listOperation = redisTemplate.opsForList();
            Long size = listOperation.size(key);
    
            for (int i = 0; i < size; i++) {
        
                dataList.add(listOperation.index(key, i));
            }
            return dataList;
        }
    
        /**
         * 缓存Set
         *
         * @param key     缓存键值
         * @param dataSet 缓存的数据
         * @return 缓存数据的对象
         */
        public <T> BoundSetOperations<String, T> setCacheSet(String key, Set<T> dataSet) {
        
            BoundSetOperations<String, T> setOperation = redisTemplate.boundSetOps(key);
            Iterator<T> it = dataSet.iterator();
            while (it.hasNext()) {
        
                setOperation.add(it.next());
            }
            return setOperation;
        }
    
        /**
         * 获得缓存的set
         *
         * @param key
         * @return
         */
        public <T> Set<T> getCacheSet(String key) {
        
            Set<T> dataSet = new HashSet<T>();
            BoundSetOperations<String, T> operation = redisTemplate.boundSetOps(key);
            dataSet = operation.members();
            return dataSet;
        }
    
        /**
         * 缓存Map
         *
         * @param key
         * @param dataMap
         * @return
         */
        public <T> HashOperations<String, String, T> setCacheMap(String key, Map<String, T> dataMap) {
        
            HashOperations hashOperations = redisTemplate.opsForHash();
            if (null != dataMap) {
        
                for (Map.Entry<String, T> entry : dataMap.entrySet()) {
        
                    hashOperations.put(key, entry.getKey(), entry.getValue());
                }
            }
            return hashOperations;
        }
    
        /**
         * 获得缓存的Map
         *
         * @param key
         * @return
         */
        public <T> Map<String, T> getCacheMap(String key) {
        
            Map<String, T> map = redisTemplate.opsForHash().entries(key);
            return map;
        }
    
        /**
         * 获得缓存的基本对象列表
         *
         * @param pattern 字符串前缀
         * @return 对象列表
         */
        public Collection<String> keys(String pattern) {
        
            return redisTemplate.keys(pattern);
        }
    }

#### SpringUtils类 ####

/**
     * @Description:  spring工具类 方便在非spring管理环境中获取bean
     * @Author: NXN [Xiangning.Nie@desaysv.com]
     * @ModifiedBy: [修改人] on [修改日期] for [修改说明]
     * @Date: 2023/3/6 17:56
     */
    @Component
    public final class SpringUtils implements BeanFactoryPostProcessor {
        
        /**
         * Spring应用上下文环境
         */
        private static ConfigurableListableBeanFactory beanFactory;
    
        @Override
        public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        
            SpringUtils.beanFactory = beanFactory;
        }
    
        /**
         * 获取对象
         *
         * @param name
         * @return Object 一个以所给名字注册的bean的实例
         * @throws BeansException
         */
        @SuppressWarnings("unchecked")
        public static <T> T getBean(String name) throws BeansException {
        
            return (T) beanFactory.getBean(name);
        }
    
        /**
         * 获取类型为requiredType的对象
         *
         * @param clz
         * @return
         * @throws BeansException
         */
        public static <T> T getBean(Class<T> clz) throws BeansException {
        
            T result = (T) beanFactory.getBean(clz);
            return result;
        }
    
        /**
         * 如果BeanFactory包含一个与所给名称匹配的bean定义，则返回true
         *
         * @param name
         * @return boolean
         */
        public static boolean containsBean(String name) {
        
            return beanFactory.containsBean(name);
        }
    
        /**
         * 判断以给定名字注册的bean定义是一个singleton还是一个prototype。
         * 如果与给定名字相应的bean定义没有被找到，将会抛出一个异常（NoSuchBeanDefinitionException）
         *
         * @param name
         * @return boolean
         * @throws NoSuchBeanDefinitionException
         */
        public static boolean isSingleton(String name) throws NoSuchBeanDefinitionException {
        
            return beanFactory.isSingleton(name);
        }
    
        /**
         * @param name
         * @return Class 注册对象的类型
         * @throws NoSuchBeanDefinitionException
         */
        public static Class<?> getType(String name) throws NoSuchBeanDefinitionException {
        
            return beanFactory.getType(name);
        }
    
        /**
         * 如果给定的bean名字在bean定义中有别名，则返回这些别名
         *
         * @param name
         * @return
         * @throws NoSuchBeanDefinitionException
         */
        public static String[] getAliases(String name) throws NoSuchBeanDefinitionException {
        
            return beanFactory.getAliases(name);
        }
    
        /**
         * 获取aop代理对象
         *
         * @param invoker
         * @return
         */
        @SuppressWarnings("unchecked")
        public static <T> T getAopProxy(T invoker) {
        
            return (T) AopContext.currentProxy();
        }
    }

#### 启动类加上注解 ####

@ComponentScan(basePackages = "com.joolun.cloud.mall.*")

![在这里插入图片描述][776f1677082444348963a9875edd78a4.png]

[776f1677082444348963a9875edd78a4.png]: https://img-blog.csdnimg.cn/776f1677082444348963a9875edd78a4.png