mybatis plus使用redis作为二级缓存的方法

时间:2021-05-19

建议缓存放到 service 层,你可以自定义自己的 BaseServiceImpl 重写注解父类方法,继承自己的实现。为了方便,这里我们将缓存放到mapper层。mybatis-plus整合redis作为二级缓存与mybatis整合redis略有不同。

1. mybatis-plus开启二级缓存

mybatis-plus.configuration.cache-enabled=true

2. 定义RedisTemplate的bean交给spring管理,这里为了能将对象直接存取到redis中,进行了一些序列化的操作

@Bean(value = "redisTemplate") public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory connectionFactory) { RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>(); redisTemplate.setConnectionFactory(connectionFactory); //Use Jackson 2Json RedisSerializer to serialize and deserialize the value of redis (default JDK serialization) Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class); ObjectMapper objectMapper = new ObjectMapper(); objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY); //将类名称序列化到json串中 objectMapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL); //设置输入时忽略JSON字符串中存在而Java对象实际没有的属性 objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false); jackson2JsonRedisSerializer.setObjectMapper(objectMapper); //Use String RedisSerializer to serialize and deserialize the key value of redis RedisSerializer redisSerializer = new StringRedisSerializer(); //key redisTemplate.setKeySerializer(redisSerializer); redisTemplate.setHashKeySerializer(redisSerializer); //value redisTemplate.setValueSerializer(jackson2JsonRedisSerializer); redisTemplate.setHashValueSerializer(jackson2JsonRedisSerializer); redisTemplate.afterPropertiesSet(); return redisTemplate; }

3. 自定义自己的缓存管理

package com.qctchina.headsetserver.config;import com.qctchina.headsetserver.util.SpringUtil;import lombok.extern.slf4j.Slf4j;import org.apache.ibatis.cache.Cache;import org.springframework.data.redis.connection.RedisServerCommands;import org.springframework.data.redis.core.RedisCallback;import org.springframework.data.redis.core.RedisTemplate;import org.springframework.util.CollectionUtils;import java.util.Set;import java.util.concurrent.locks.ReadWriteLock;import java.util.concurrent.locks.ReentrantReadWriteLock;/** * @author shuangyueliao * @create 2019/9/10 14:02 * @Version 0.1 */@Slf4jpublic class MybatisRedisCache implements Cache { // 读写锁 private final ReadWriteLock readWriteLock = new ReentrantReadWriteLock(true); //这里使用了redis缓存,使用springboot自动注入 private RedisTemplate<String, Object> redisTemplate; private String id; public MybatisRedisCache(final String id) { if (id == null) { throw new IllegalArgumentException("Cache instances require an ID"); } this.id = id; } @Override public String getId() { return this.id; } @Override public void putObject(Object key, Object value) { if (redisTemplate == null) { //由于启动期间注入失败,只能运行期间注入,这段代码可以删除 redisTemplate = (RedisTemplate<String, Object>) SpringUtil.getBean("redisTemplate"); } if (value != null) { redisTemplate.opsForValue().set(key.toString(), value); } } @Override public Object getObject(Object key) { if (redisTemplate == null) { //由于启动期间注入失败,只能运行期间注入,这段代码可以删除 redisTemplate = (RedisTemplate<String, Object>) SpringUtil.getBean("redisTemplate"); } try { if (key != null) { return redisTemplate.opsForValue().get(key.toString()); } } catch (Exception e) { e.printStackTrace(); log.error("缓存出错 "); } return null; } @Override public Object removeObject(Object key) { if (redisTemplate == null) { //由于启动期间注入失败,只能运行期间注入,这段代码可以删除 redisTemplate = (RedisTemplate<String, Object>) SpringUtil.getBean("redisTemplate"); } if (key != null) { redisTemplate.delete(key.toString()); } return null; } @Override public void clear() { log.debug("清空缓存"); if (redisTemplate == null) { redisTemplate = (RedisTemplate<String, Object>) SpringUtil.getBean("redisTemplate"); } Set<String> keys = redisTemplate.keys("*:" + this.id + "*"); if (!CollectionUtils.isEmpty(keys)) { redisTemplate.delete(keys); } } @Override public int getSize() { if (redisTemplate == null) { //由于启动期间注入失败,只能运行期间注入,这段代码可以删除 redisTemplate = (RedisTemplate<String, Object>) SpringUtil.getBean("redisTemplate"); } Long size = redisTemplate.execute((RedisCallback<Long>) RedisServerCommands::dbSize); return size.intValue(); } @Override public ReadWriteLock getReadWriteLock() { return this.readWriteLock; }}

SpringUtil是手动获取bean的工具类

@Componentpublic class SpringUtil implements ApplicationContextAware { private static ApplicationContext applicationContext; @Override public void setApplicationContext(ApplicationContext applicationContext) throws BeansException { SpringUtil.applicationContext = applicationContext; } public static Object getBean(String name){ return applicationContext.getBean(name); } public static <T> T getBean(String name, Class<T> clazz){ return applicationContext.getBean(name, clazz); } public static <T> T getBean(Class<T> clazz){ return applicationContext.getBean(clazz); }}

4. 在mapper上加上注解@CacheNamespace

@CacheNamespace(implementation= MybatisRedisCache.class,eviction=MybatisRedisCache.class)public interface CommonMapper extends BaseMapper<Common> {

如果调用该mapper下的方法,那么会使用redis缓存

总结

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