介紹
使用mybatis時可以使用二級緩存提高查詢速度，進而改善用戶體驗。
使用redis做mybatis的二級緩存可是內存可控<如將單獨的服務器部署出來用於二級緩存>，管理方便。
1.在pom.xml文件中引入redis依賴
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-redis</artifactId></dependency>
2.在application.properties配置文件中進行redis的配置
## Redis spring.redis.database=0spring.redis.host=172.16.3.123spring.redis.port=6379spring.redis.password=spring.redis.pool.max-active=8spring.redis.pool.max-wait=-1spring.redis.pool.max-idle=8spring.redis.pool.min-idle=0spring.redis.timeout=0
3.創建cache包，然後創建兩個類，一個ApplicationContextHolder實現ApplicationContextAware接口，具體內容如下
package com.ruijie.SpringBootandRedis.cache;import org.springframework.beans.BeansException;import org.springframework.context.ApplicationContext;import org.springframework.context.ApplicationContextAware;import org.springframework.stereotype.Component;@Componentpublic class ApplicationContextHolder implements ApplicationContextAware { private static ApplicationContext applicationContext; @Override public void setApplicationContext(ApplicationContext ctx) throws BeansException { applicationContext = ctx; } /** * Get application context from everywhere * * @return */ public static ApplicationContext getApplicationContext() { return applicationContext; } /** * Get bean by class * * @param clazz * @param <T> * @return */ public static <T> T getBean(Class<T> clazz) { return applicationContext.getBean(clazz); } /** * Get bean by class name * * @param name * @param <T> * @return */ public static <T> T getBean(String name) { return (T) applicationContext.getBean(name); }}4.創建RedisCache類實現Cache接口，具體內容如下：
package com.ruijie.SpringBootandRedis.cache;import org.apache.ibatis.cache.Cache;import org.slf4j.Logger;import org.slf4j.LoggerFactory;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 static final Logger logger = LoggerFactory.getLogger(RedisCache.class); private final ReadWriteLock readWriteLock = new ReentrantReadWriteLock(); private final String id; // cache instance id private RedisTemplate redisTemplate; private static final long EXPIRE_TIME_IN_MINUTES = 30; // redis過期時間public RedisCache(String id) { if (id == null) { throw new IllegalArgumentException("Cache instances require 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) { try { RedisTemplate redisTemplate = getRedisTemplate(); ValueOperations opsForValue = redisTemplate.opsForValue(); opsForValue.set(key, value, EXPIRE_TIME_IN_MINUTES, TimeUnit.MINUTES); logger.debug("Put query result to redis"); } catch (Throwable t) { logger.error("Redis put failed", t); } } /** * Get cached query result from redis * * @param key * @return */ @Override public Object getObject(Object key) { try { RedisTemplate redisTemplate = getRedisTemplate(); ValueOperations opsForValue = redisTemplate.opsForValue(); logger.debug("Get cached query result from redis"); System.out.println("****"+opsForValue.get(key).toString()); return opsForValue.get(key); } catch (Throwable t) { logger.error("Redis get failed, fail over to db", t); return null; } } /** * Remove cached query result from redis * * @param key * @return */ @Override @SuppressWarnings("unchecked") public Object removeObject(Object key) { try { RedisTemplate redisTemplate = getRedisTemplate(); redisTemplate.delete(key); logger.debug("Remove cached query result from redis"); } catch (Throwable t) { logger.error("Redis remove failed", t); } return null; } /** * Clears this cache instance */ @Override public void clear() { RedisTemplate redisTemplate = getRedisTemplate(); redisTemplate.execute((RedisCallback) connection -> { connection.flushDb(); return null; }); logger.debug("Clear all the cached query result from redis"); } /** * This method is not used * * @return */ @Override public int getSize() { return 0; } @Override public ReadWriteLock getReadWriteLock() { return readWriteLock; } private RedisTemplate getRedisTemplate() { if (redisTemplate == null) { redisTemplate = ApplicationContextHolder.getBean("redisTemplate"); } return redisTemplate; }}5.實體類中要實現Serializable接口，並且要聲明序列號
private static final long serialVersionUID = -2566441764189220519L;
6.開啟Mybatis的二級緩存
在pom.xml配置文件中配置
mybatis.configuration.cache-enabled=true
在mapper接口中加入
@CacheNamespace(implementation=(com.demo.testdemo.cache.RedisCache.class))
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持武林網。