2015做那些网站能致富,网站建设审批表,如何提高wordpress的反应速度,青海wap网站建设公司文章目录 前言IBloomFilterObjectMapUtilsCacheClient使用示例具体业务的布隆过滤器控制层服务层 前言
该工具类包含以下功能#xff1a;
1.将任意对象存储在 hash 类型的 key 中#xff0c;并可以设置 TTL
2.将任意对象存储在 hash 类型的 key 中#xff0c;并且可以设置… 文章目录 前言IBloomFilterObjectMapUtilsCacheClient使用示例具体业务的布隆过滤器控制层服务层 前言
该工具类包含以下功能
1.将任意对象存储在 hash 类型的 key 中并可以设置 TTL
2.将任意对象存储在 hash 类型的 key 中并且可以设置逻辑过期时间
3.将空对象存入 hash 类型的 key 中并且可以设置超时时间
4.缓存空对象解决缓存穿透
5.布隆过滤器解决缓存穿透
6.布隆过滤器缓存空对象解决缓存穿透
7.互斥锁解决缓存击穿
8.逻辑过期解决缓存击穿
以下是关键代码
IBloomFilter
IBloomFilter 是自定义的布隆过滤器接口。这里使用接口的原因在于每个业务使用的布隆过滤器可能是不一样的因此为了让工具类能兼容所有的布隆过滤器这里添加接口并使用泛型表示布隆过滤器内部存储数据的类型
public interface IBloomFilterT {// 添加void add(T id);// 判断是否存在boolean mightContain(T id);}ObjectMapUtils
ObjectMapUtils 是对象与 Map 类型的相互转换可以让对象转换为 Map 集合也可以让 Map 集合转回对象
public class ObjectMapUtils {// 将对象转为 Mappublic static MapString, String obj2Map(Object obj) throws IllegalAccessException {MapString, String result new HashMap();Class? clazz obj.getClass();Field[] fields clazz.getDeclaredFields();for (Field field : fields) {// 如果为 static 且 final 则跳过if (Modifier.isStatic(field.getModifiers()) Modifier.isFinal(field.getModifiers())) {continue;}field.setAccessible(true); // 设置为可访问私有字段Object fieldValue field.get(obj);if (fieldValue ! null) {result.put(field.getName(), field.get(obj).toString());}}return result;}// 将 Map 转为对象public staticR R map2Obj(MapObject, Object map, ClassR clazz) throws Exception {R obj clazz.getDeclaredConstructor().newInstance();for (Map.EntryObject, Object entry : map.entrySet()) {Object fieldName entry.getKey();Object fieldValue entry.getValue();Field field clazz.getDeclaredField(fieldName.toString());field.setAccessible(true); // 设置为可访问私有字段String fieldValueStr fieldValue.toString();// 根据字段类型进行转换fillField(obj, field, fieldValueStr);}return obj;}// 将 Map 转为对象含排除字段public staticR R map2Obj(MapObject, Object map, ClassR clazz, String... excludeFields) throws Exception {R obj clazz.getDeclaredConstructor().newInstance();for (Map.EntryObject, Object entry : map.entrySet()) {Object fieldName entry.getKey();if(Arrays.asList(excludeFields).contains(fieldName)) {continue;}Object fieldValue entry.getValue();Field field clazz.getDeclaredField(fieldName.toString());field.setAccessible(true); // 设置为可访问私有字段String fieldValueStr fieldValue.toString();// 根据字段类型进行转换fillField(obj, field, fieldValueStr);}return obj;}// 填充字段private static void fillField(Object obj, Field field, String value) throws IllegalAccessException {if (field.getType().equals(int.class) || field.getType().equals(Integer.class)) {field.set(obj, Integer.parseInt(value));} else if (field.getType().equals(boolean.class) || field.getType().equals(Boolean.class)) {field.set(obj, Boolean.parseBoolean(value));} else if (field.getType().equals(double.class) || field.getType().equals(Double.class)) {field.set(obj, Double.parseDouble(value));} else if (field.getType().equals(long.class) || field.getType().equals(Long.class)) {field.set(obj, Long.parseLong(value));} else if (field.getType().equals(String.class)) {field.set(obj, value);} else if(field.getType().equals(LocalDateTime.class)) {field.set(obj, LocalDateTime.parse(value));}// 如果有需要可以继续添加...}}CacheClient
CacheClient 就是缓存工具类包含了之前提到的所有功能
Component
Slf4j
public class CacheClient {Autowiredprivate StringRedisTemplate redisTemplate;// 重建缓存线程池private static final ExecutorService CACHE_REBUILD_EXECUTOR Executors.newFixedThreadPool(10);// 将任意对象存储在 hash 类型的 key 中并可以设置 TTLpublic void setByHash(String key, Object value, Long time, TimeUnit unit) throws IllegalAccessException {redisTemplate.opsForHash().putAll(key, ObjectMapUtils.obj2Map(value));redisTemplate.expire(key, time, unit);}// 将任意对象存储在 hash 类型的 key 中并且可以设置逻辑过期时间public void setWithLogicalExpireByHash(String key, Object value, Long time, TimeUnit unit) throws IllegalAccessException {MapString, String map ObjectMapUtils.obj2Map(value);// 添加逻辑过期时间map.put(RedisConstants.EXPIRE_KEY, LocalDateTime.now().plusSeconds(unit.toSeconds(time)).toString());redisTemplate.opsForHash().putAll(key, map);}// 将空对象存入 hash 类型的 key 中并且可以设置超时时间public void setNullByHash(String key, Long time, TimeUnit unit) {redisTemplate.opsForHash().put(key, , );redisTemplate.expire(key, time, unit);}// 尝试加锁private boolean tryLock(String key, Long time, TimeUnit unit) {Boolean isLocked redisTemplate.opsForValue().setIfAbsent(key,1, time, unit);return Boolean.TRUE.equals(isLocked);}// 解锁private void unlock(String key) {redisTemplate.delete(key);}// 缓存空对象解决缓存穿透publicR, ID R queryWithCacheNull(String keyPrefix, ID id, ClassR clazz, FunctionID, R dbFallback,Long time, TimeUnit unit) {// 从 redis 查询String key keyPrefix id;MapObject, Object entries redisTemplate.opsForHash().entries(key);// 缓存命中if (!entries.isEmpty()) {try {// 如果是空对象表示一定不存在数据库中直接返回解决缓存穿透if (entries.containsKey()) {log.info(redis查询到id{}的空对象, id);return null;}// 刷新有效期redisTemplate.expire(key, time, unit);R r ObjectMapUtils.map2Obj(entries, clazz);log.info(缓存命中结果为{}, r);return r;} catch (Exception e) {throw new RuntimeException(e);}}// 查询数据库R r dbFallback.apply(id);if (r null) {log.info(id{}不存在于数据库存入redis, id);// 存入空值setNullByHash(key, RedisConstants.CACHE_NULL_TTL, TimeUnit.MINUTES);// 不存在直接返回return null;}// 存在写入 redistry {setByHash(key, r, time, unit);} catch (IllegalAccessException e) {throw new RuntimeException(e);}log.info(查询数据库获取结果{}, r);return r;}// 布隆过滤器解决缓存穿透publicR, ID R queryWithBloom(String keyPrefix, ID id, ClassR clazz, FunctionID, R dbFallback,Long time, TimeUnit unit, IBloomFilterID bloomFilter) {// 如果不在布隆过滤器中直接返回if (!bloomFilter.mightContain(id)) {log.info(id{}不存在于布隆过滤器, id);return null;}// 从 redis 查询String key keyPrefix id;MapObject, Object entries redisTemplate.opsForHash().entries(key);// 缓存命中if (!entries.isEmpty()) {try {// 刷新有效期redisTemplate.expire(key, time, unit);R r ObjectMapUtils.map2Obj(entries, clazz);log.info(缓存命中结果为{}, r);return r;} catch (Exception e) {throw new RuntimeException(e);}}// 查询数据库R r dbFallback.apply(id);if (r null) {log.info(id{}不存在于数据库, id);// 不存在直接返回return null;}// 存在写入 redistry {setByHash(key, r, time, unit);} catch (IllegalAccessException e) {throw new RuntimeException(e);}log.info(查询数据库获取结果{}, r);return r;}// 布隆过滤器缓存空对象解决缓存穿透publicR, ID R queryWithBloomAndCacheNull(String keyPrefix, ID id, ClassR clazz, FunctionID, R dbFallback,Long time, TimeUnit unit, IBloomFilterID bloomFilter) {// 如果不在布隆过滤器中直接返回if (!bloomFilter.mightContain(id)) {log.info(id{}不存在于布隆过滤器, id);return null;}// 从 redis 查询String key keyPrefix id;MapObject, Object entries redisTemplate.opsForHash().entries(key);// 缓存命中if (!entries.isEmpty()) {try {// 如果是空对象表示一定不存在数据库中直接返回解决缓存穿透if (entries.containsKey()) {log.info(redis查询到id{}的空对象, id);return null;}// 刷新有效期redisTemplate.expire(key, RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);R r ObjectMapUtils.map2Obj(entries, clazz);log.info(缓存命中结果为{}, r);return r;} catch (Exception e) {throw new RuntimeException(e);}}// 查询数据库R r dbFallback.apply(id);if (r null) {log.info(id{}不存在于数据库存入redis, id);// 存入空值setNullByHash(key, RedisConstants.CACHE_NULL_TTL, TimeUnit.MINUTES);// 不存在直接返回return null;}// 存在写入 redistry {setByHash(key, r, time, unit);} catch (IllegalAccessException e) {throw new RuntimeException(e);}log.info(查询数据库获取结果{}, r);return r;}// 互斥锁解决缓存击穿publicR, ID R queryWithMutex(String keyPrefix, ID id, ClassR clazz, FunctionID, R dbFallback,Long cacheTime, TimeUnit cacheUnit, String lockKeyPrefix,Long lockTime, TimeUnit lockUnit) {String key keyPrefix id;String lockKey lockKeyPrefix id;boolean flag false;int cnt 10; // 重试次数try {do {// 从 redis 查询MapObject, Object entries redisTemplate.opsForHash().entries(key);// 缓存命中if (!entries.isEmpty()) {try {// 刷新有效期redisTemplate.expire(key, RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);R r ObjectMapUtils.map2Obj(entries, clazz);log.info(缓存命中结果为{}, r);return r;} catch (Exception e) {throw new RuntimeException(e);}}// 缓存未命中尝试获取互斥锁log.info(缓存未命中尝试获取互斥锁 id{}, id);flag tryLock(lockKey, lockTime, lockUnit);if (flag) { // 获取成功进行下一步log.info(成功获取互斥锁 id{}, id);break;}// 获取失败睡眠后重试Thread.sleep(50);} while ((--cnt) ! 0); // 未获取到锁休眠后重试if(!flag) { // 重试次数到达上限log.info(重试次数达到上限 id{}, id);return null;}// 查询数据库R r dbFallback.apply(id);if (r null) {log.info(id{}不存在于数据库, id);// 不存在直接返回return null;}// 存在写入 redistry {setByHash(key, r, cacheTime, cacheUnit);} catch (IllegalAccessException e) {throw new RuntimeException(e);}log.info(查询数据库获取结果{}, r);return r;} catch (InterruptedException e) {throw new RuntimeException(e);} finally {if (flag) { // 获取了锁需要释放log.info(解锁id{}, id);unlock(lockKey);}}}// 逻辑过期解决缓存击穿publicR, ID R queryWithLogicalExpire(String keyPrefix, ID id, ClassR clazz, FunctionID, R dbFallback,Long expireTime, TimeUnit expireUnit,String lockKeyPrefix, Long lockTime, TimeUnit lockUnit) {String key keyPrefix id;String lockKey lockKeyPrefix id;// 从 redis 查询MapObject, Object entries redisTemplate.opsForHash().entries(key);// 缓存未命中返回空if(entries.isEmpty()) {log.info(缓存未命中返回空 id{}, id);return null;}try {R r ObjectMapUtils.map2Obj(entries, clazz, RedisConstants.EXPIRE_KEY);LocalDateTime expire LocalDateTime.parse(entries.get(RedisConstants.EXPIRE_KEY).toString());// 判断缓存是否过期if(expire.isAfter(LocalDateTime.now())) {// 未过期则直接返回log.info(缓存未过期结果为{}, r);return r;}// 过期需要先尝试获取互斥锁log.info(尝试获取互斥锁 id{}, id);if(tryLock(lockKey, lockTime, lockUnit)) {log.info(获得到互斥锁 id{}, id);// 获取成功// 双重检验entries redisTemplate.opsForHash().entries(key);r ObjectMapUtils.map2Obj(entries, clazz, RedisConstants.EXPIRE_KEY);expire LocalDateTime.parse(entries.get(RedisConstants.EXPIRE_KEY).toString());if(expire.isAfter(LocalDateTime.now())) {// 未过期则直接返回log.info(缓存未过期结果为{}, r);log.info(解锁 id{}, id);unlock(lockKey);return r;}// 通过线程池完成重建缓存任务CACHE_REBUILD_EXECUTOR.submit(() - {try {log.info(进行重建缓存任务 id{}, id);setWithLogicalExpireByHash(key, dbFallback.apply(id), expireTime, expireUnit);} catch (Exception e) {throw new RuntimeException(e);} finally {log.info(解锁 id{}, id);unlock(lockKey);}});}log.info(返回结果{}, r);return r;} catch (Exception e) {throw new RuntimeException(e);}}}使用示例
具体业务的布隆过滤器
public class ShopBloomFilter implements IBloomFilterLong {private BloomFilterLong bloomFilter;public ShopBloomFilter(ShopMapper shopMapper) {// 初始化布隆过滤器设计预计元素数量为100_0000L误差率为1%bloomFilter BloomFilter.create(Funnels.longFunnel(), 100_0000, 0.01);// 将数据库中已有的店铺 id 加入布隆过滤器ListShop shops shopMapper.selectList(null);for (Shop shop : shops) {bloomFilter.put(shop.getId());}}public void add(Long id) {bloomFilter.put(id);}public boolean mightContain(Long id){return bloomFilter.mightContain(id);}}控制层
/*** 根据id查询商铺信息* param id 商铺id* return 商铺详情数据*/
GetMapping(/{id})
public Result queryShopById(PathVariable(id) Long id) {return shopService.queryShopById(id);
}服务层
Override
public Result queryShopById(Long id) {// 缓存空对象解决缓存穿透/*Shop shop cacheClient.queryWithCacheNull(RedisConstants.CACHE_SHOP_KEY,id, Shop.class, this::getById, RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);*/// 布隆过滤器解决缓存穿透/*Shop shop cacheClient.queryWithBloom(RedisConstants.CACHE_SHOP_KEY,id, Shop.class, this::getById, RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES, shopBloomFilter);*/// 布隆过滤器缓存空对象解决缓存穿透/*Shop shop cacheClient.queryWithBloomAndCacheNull(RedisConstants.CACHE_SHOP_KEY,id, Shop.class, this::getById, RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES, shopBloomFilter);*/// 互斥锁解决缓存击穿/*Shop shop cacheClient.queryWithMutex(RedisConstants.CACHE_SHOP_KEY, id, Shop.class, this::getById,RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES,RedisConstants.LOCK_SHOP_KEY, RedisConstants.LOCK_SHOP_TTL, TimeUnit.SECONDS);*/// 逻辑过期解决缓存击穿Shop shop cacheClient.queryWithLogicalExpire(RedisConstants.CACHE_SHOP_KEY, id, Shop.class, this::getById,RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES,RedisConstants.LOCK_SHOP_KEY, RedisConstants.LOCK_SHOP_TTL, TimeUnit.SECONDS);if(shop null) {return Result.fail(商铺不存在);}return Result.ok(shop);
}
