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Today, I will talk to you about how to use redis as a secondary cache in mybatis plus. Many people may not know much about it. In order to make you understand better, the editor has summarized the following for you. I hope you can get something according to this article.

1. Mybatis-plus enables secondary cache

Mybatis-plus.configuration.cache-enabled=true

two。 The bean that defines RedisTemplate is managed by spring. In order to access the object directly into redis, some serialization operations @ Bean (value = "redisTemplate") public RedisTemplate redisTemplate (RedisConnectionFactory connectionFactory) {RedisTemplate redisTemplate = new RedisTemplate (); redisTemplate.setConnectionFactory (connectionFactory); / / Use Jackson2JsonRedisSerializer 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); / / serialize the class name to objectMapper.enableDefaultTyping (ObjectMapper.DefaultTyping.NON_FINAL) in the json string; / / set the attribute objectMapper.configure (DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false) that exists in the JSON string but does not actually exist in the Java object when setting input; jackson2JsonRedisSerializer.setObjectMapper (objectMapper) / / Use StringRedisSerializer 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. Customize your own cache management 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 14:02 on 2019-9-10 * @ Version 0.1 * / @ Slf4jpublic class MybatisRedisCache implements Cache {/ / read-write lock private final ReadWriteLock readWriteLock = new ReentrantReadWriteLock (true); / / redis cache is used here, and private RedisTemplate redisTemplate; private String id; public MybatisRedisCache (final String id) {if (id = = null) {throw new IllegalArgumentException ("Cache instances require an ID") is automatically injected using springboot. } this.id = id;} @ Override public String getId () {return this.id;} @ Override public void putObject (Object key, Object value) {if (redisTemplate = = null) {/ / because injection failed during startup, only injection can be run during startup. This code can delete redisTemplate = (RedisTemplate) SpringUtil.getBean ("redisTemplate"). } if (value! = null) {redisTemplate.opsForValue () .set (key.toString (), value);} @ Override public Object getObject (Object key) {if (redisTemplate = = null) {/ / because injection failed during startup, only injection can be run during startup. This code can delete redisTemplate = (RedisTemplate) SpringUtil.getBean ("redisTemplate"). } try {if (key! = null) {return redisTemplate.opsForValue () .get (key.toString ());} catch (Exception e) {e.printStackTrace (); log.error ("cache error");} return null } @ Override public Object removeObject (Object key) {if (redisTemplate = = null) {/ / due to injection failure during startup, only injection during startup can be run. This code can delete redisTemplate = (RedisTemplate) SpringUtil.getBean ("redisTemplate");} if (key! = null) {redisTemplate.delete (key.toString ());} return null } @ Override public void clear () {log.debug ("clear cache"); if (redisTemplate = = null) {redisTemplate = (RedisTemplate) SpringUtil.getBean ("redisTemplate");} Set keys = redisTemplate.keys ("*:" + this.id + "*"); if (! CollectionUtils.isEmpty (keys)) {redisTemplate.delete (keys) } @ Override public int getSize () {if (redisTemplate = = null) {/ / due to injection failure during startup, only injection during startup can be run. This code can delete redisTemplate = (RedisTemplate) SpringUtil.getBean ("redisTemplate");} Long size = redisTemplate.execute ((RedisCallback) RedisServerCommands::dbSize); return size.intValue () } @ Override public ReadWriteLock getReadWriteLock () {return this.readWriteLock;}}

SpringUtil is a tool class that gets bean manually.

@ 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 getBean (String name, Class clazz) {return applicationContext.getBean (name, clazz);} public static T getBean (Class clazz) {return applicationContext.getBean (clazz);}} 4. Annotate @ CacheNamespace@CacheNamespace (implementation= MybatisRedisCache.class,eviction=MybatisRedisCache.class) public interface CommonMapper extends BaseMapper on mapper {if the method under this mapper is called, the redis cache will be used

After reading the above, do you have any further understanding of how to use redis as a secondary cache in mybatis plus? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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