SpringBoot+MyBatis+Redis(二級快取)
阿新 • • 發佈：2020-09-11
應用場景:
儲存大資料量，避免重複請求。
一、新增Maven依賴
<!-- SpringBoot Boot Redis -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
二、編寫Redis相關類
RedisService.java
import java.util.Collection; import java.util.List; import java.util.Map; import java.util.Set; import java.util.concurrent.TimeUnit; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.data.redis.core.HashOperations; import org.springframework.data.redis.core.RedisTemplate; import org.springframework.data.redis.core.ValueOperations; import org.springframework.stereotype.Component; @SuppressWarnings(value= { "unchecked", "rawtypes" }) @Component public class RedisService { @Autowired public RedisTemplate redisTemplate; /** * 快取基本的物件，Integer、String、實體類等 * * @param key 快取的鍵值 * @param value 快取的值 */ public <T> void setCacheObject(final String key, final T value) { redisTemplate.opsForValue().set(key, value); } /** * 快取基本的物件，Integer、String、實體類等 * * @param key 快取的鍵值 * @param value 快取的值 * @param timeout 時間 * @param timeUnit 時間顆粒度 */ public <T> void setCacheObject(final String key, final T value, final Integer timeout, final TimeUnit timeUnit) { redisTemplate.opsForValue().set(key, value, timeout, timeUnit); } /** * 設定有效時間 * * @param key Redis鍵 * @param timeout 超時時間 * @return true=設定成功；false=設定失敗 */ public boolean expire(final String key, final long timeout) { return expire(key, timeout, TimeUnit.SECONDS); } /** * 設定有效時間 * * @param key Redis鍵 * @param timeout 超時時間 * @param unit 時間單位 * @return true=設定成功；false=設定失敗 */ public boolean expire(final String key, final long timeout, final TimeUnit unit) { return redisTemplate.expire(key, timeout, unit); } /** * 獲得快取的基本物件。 * * @param key 快取鍵值 * @return 快取鍵值對應的資料 */ public <T> T getCacheObject(final String key) { ValueOperations<String, T> operation = redisTemplate.opsForValue(); return operation.get(key); } /** * 刪除單個物件 * * @param key */ public boolean deleteObject(final String key) { return redisTemplate.delete(key); } /** * 刪除集合物件 * * @param collection 多個物件 * @return */ public long deleteObject(final Collection collection) { return redisTemplate.delete(collection); } /** * 快取List資料 * * @param key 快取的鍵值 * @param dataList 待快取的List資料 * @return 快取的物件 */ public <T> long setCacheList(final String key, final List<T> dataList) { Long count = redisTemplate.opsForList().rightPushAll(key, dataList); return count == null ? 0 : count; } /** * 獲得快取的list物件 * * @param key 快取的鍵值 * @return 快取鍵值對應的資料 */ public <T> List<T> getCacheList(final String key) { return redisTemplate.opsForList().range(key, 0, -1); } /** * 快取Set * * @param key 快取鍵值 * @param dataSet 快取的資料 * @return 快取資料的物件 */ public <T> long setCacheSet(final String key, final Set<T> dataSet) { Long count = redisTemplate.opsForSet().add(key, dataSet); return count == null ? 0 : count; } /** * 獲得快取的set * * @param key * @return */ public <T> Set<T> getCacheSet(final String key) { return redisTemplate.opsForSet().members(key); } /** * 快取Map * * @param key * @param dataMap */ public <T> void setCacheMap(final String key, final Map<String, T> dataMap) { if (dataMap != null) { redisTemplate.opsForHash().putAll(key, dataMap); } } /** * 獲得快取的Map * * @param key * @return */ public <T> Map<String, T> getCacheMap(final String key) { return redisTemplate.opsForHash().entries(key); } /** * 往Hash中存入資料 * * @param key Redis鍵 * @param hKey Hash鍵 * @param value 值 */ public <T> void setCacheMapValue(final String key, final String hKey, final T value) { redisTemplate.opsForHash().put(key, hKey, value); } /** * 獲取Hash中的資料 * * @param key Redis鍵 * @param hKey Hash鍵 * @return Hash中的物件 */ public <T> T getCacheMapValue(final String key, final String hKey) { HashOperations<String, String, T> opsForHash = redisTemplate.opsForHash(); return opsForHash.get(key, hKey); } /** * 獲取多個Hash中的資料 * * @param key Redis鍵 * @param hKeys Hash鍵集合 * @return Hash物件集合 */ public <T> List<T> getMultiCacheMapValue(final String key, final Collection<Object> hKeys) { return redisTemplate.opsForHash().multiGet(key, hKeys); } /** * 獲得快取的基本物件列表 * * @param pattern 字串字首 * @return 物件列表 */ public Collection<String> keys(final String pattern) { return redisTemplate.keys(pattern); } }
RedisConfig.java
import org.springframework.cache.annotation.CachingConfigurerSupport; import org.springframework.cache.annotation.EnableCaching; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.data.redis.connection.RedisConnectionFactory; import org.springframework.data.redis.core.RedisTemplate; import org.springframework.data.redis.serializer.StringRedisSerializer; import com.fasterxml.jackson.annotation.JsonAutoDetect; import com.fasterxml.jackson.annotation.PropertyAccessor; import com.fasterxml.jackson.databind.ObjectMapper; @Configuration @EnableCaching public class RedisConfig extends CachingConfigurerSupport { @Bean @SuppressWarnings(value = { "unchecked", "rawtypes", "deprecation" }) public RedisTemplate<Object, Object> redisTemplate(RedisConnectionFactory connectionFactory) { RedisTemplate<Object, Object> template = new RedisTemplate<>(); template.setConnectionFactory(connectionFactory); FastJson2JsonRedisSerializer serializer = new FastJson2JsonRedisSerializer(Object.class); ObjectMapper mapper = new ObjectMapper(); mapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY); mapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL); serializer.setObjectMapper(mapper); template.setValueSerializer(serializer); // 使用StringRedisSerializer來序列化和反序列化redis的key值 template.setKeySerializer(new StringRedisSerializer()); template.afterPropertiesSet(); return template; } }
RedisCache.java
import org.apache.ibatis.cache.Cache; import org.springframework.data.redis.core.RedisCallback; import org.springframework.data.redis.core.RedisTemplate; import org.springframework.data.redis.core.ValueOperations; import java.util.concurrent.TimeUnit; import java.util.concurrent.locks.ReadWriteLock; import java.util.concurrent.locks.ReentrantReadWriteLock; public class RedisCache implements Cache { private final ReadWriteLock readWriteLock = new ReentrantReadWriteLock(); private final String id; private RedisTemplate redisTemplate; //redis過期時間 private static final long EXPIRE_TIME_IN_MINUTES = 30; public RedisCache(String id) { if (id == null) { throw new IllegalArgumentException("Cache instance required an ID"); } this.id = id; } @Override public String getId() { return id; } /** * Put query result to redis * * @Param key * @Param value */ @Override public void putObject(Object key, Object value) { RedisTemplate redisTemplate = getRedisTemplate(); ValueOperations opsForValue = redisTemplate.opsForValue(); System.out.println(key + ": key"); System.out.println(key.toString() + ": key.toString()"); System.out.println(value + ": value"); System.out.println(value.toString() + ": value.toString()"); opsForValue.set(key.toString(), value, EXPIRE_TIME_IN_MINUTES, TimeUnit.MINUTES); System.out.println("結果成功放入快取 and " + "key = " + "\n" + key + "value = " + value); System.out.println(opsForValue.get(key.toString())); } /** * Get cached query result to redis * * @Param key * @Return */ @Override public Object getObject(Object key) { RedisTemplate redisTemplate = getRedisTemplate(); // redisTemplate.setHashValueSerializer(new StringRedisSerializer()); ValueOperations opsForValue = redisTemplate.opsForValue(); System.out.println("結果從快取中獲取"); return opsForValue.get(key.toString()); } /** * Remove cached query result to redis * * @Param key * @Return */ @Override public Object removeObject(Object key) { RedisTemplate redisTemplate = getRedisTemplate(); redisTemplate.delete(key); System.out.println("從快取中刪除"); return null; } /** * Clear this cache instance */ @Override public void clear() { RedisTemplate redisTemplate = getRedisTemplate(); redisTemplate.execute((RedisCallback) connection -> { connection.flushDb(); return null; }); System.out.println("清空快取"); } @Override public int getSize() { Long size = (Long) redisTemplate.execute((RedisCallback) connection -> connection.dbSize()); return size.intValue(); } @Override public ReadWriteLock getReadWriteLock() { return readWriteLock; } private RedisTemplate getRedisTemplate() { if (redisTemplate == null) { redisTemplate = ApplicationContextHolder.getBean("redisTemplate"); } return redisTemplate; } }
三、yml配置redis
spring: redis: host: localhost port: 6379 password:
四、在DAO類新增該註解
@CacheNamespace(implementation = RedisCache.class)
五、實現類或者在Controller加如下程式碼，鍵值對儲存對應的資料
@Autowired private RedisService redisService;
六、如何確保Redis資料實時更新
我研究了下，通常如下:
1.先刪快取，再更新資料庫
2.先寫資料庫，再刪快取
參考:
Redis快取如何保證一致性