SpringBoot+Mybatis项目使用redis做Mybatis的二级缓存

1.在pom.xml文件中引入redis依赖

<dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-data-redis</artifactId>        </dependency>

2.在application.properties配置文件中进行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.创建cache包，然后创建两个类，一个ApplicationContextHolder实现ApplicationContextAware接口，具体内容如下

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.创建RedisCache类实现Cache接口，具体内容如下：

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过期时间    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.实体类中要实现Serializable接口，并且要声明序列号

private static final long serialVersionUID = -2566441764189220519L;

6.开启Mybatis的二级缓存

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))