How Redis caches data
Table of contents
step
Fetch the cache before saving the cache
Determine whether the key exists. If it exists, take the cached value directly. If it does not exist, check the data from the database and store the value in redis.
case:
@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;
}
in
RedisCache class
/**
* @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);
}
}
Spring Utils class
/**
* @Description: spring工具类 方便在非spring管理环境中获取bean
* @Author: NXN [[email protected]]
* @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();
}
}
Annotate the startup class
@ComponentScan(basePackages = "com.joolun.cloud.mall.*")
