introduce
When using mybatis, you can use the secondary cache to increase query speed and thus improve the user experience.
Use redis to make mybatis' secondary cache, but the memory is controllable. If a separate server is deployed for secondary cache>, it is easy to manage.
1.Introduce redis dependencies in pom.xml file
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-redis</artifactId></dependency>
2. Configure redis in the application.properties configuration file
## 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. Create a cache package, and then create two classes, one ApplicationContextHolder implements the ApplicationContextAware interface. The specific content is as follows
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. Create the RedisCache class to implement the Cache interface, the specific content is as follows:
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 expiration time 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 removed 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. The Serializable interface should be implemented in the entity class and the sequence number should be declared.
private static final long serialVersionUID = -2566441764189220519L;
6. Turn on Mybatis' Level 2 cache
Configure in pom.xml configuration file
mybatis.configuration.cache-enabled=true
Add to mapper interface
@CacheNamespace(implementation=(com.demo.testdemo.cache.RedisCache.class))
The above is all the content of this article. I hope it will be helpful to everyone's learning and I hope everyone will support Wulin.com more.