mybatis plus使用redis作为二级缓存的方法

mybatis plus使用redis作为二级缓存的方法

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 redisTemplate(RedisConnectionFactory connectionFactory) {

RedisTemplate 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(objectMappeBDgPAWHZor);

//Use String RedisSerializer to serialize and deserialize the key value of redis

RedisSerializer redisSerializer = new StringRedisSerializer();

//key

redisTemplate.setKeySerializer(rBDgPAWHZoedisSerializer);

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

*/

@Slf4j

public class MybatisRedisCache implements Cache {

// 读写锁

private final ReadWriteLock readBDgPAWHZoWriteLock = new ReentrantReadWriteLock(true);

//这里使用了redis缓存，使用springboot自动注入

private RedisTemplate 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) 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) 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) 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) SpringUtil.getBean("redisTemplate");

}

Set 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) SpringUtil.getBean("redisTemplate");

}

Long size = redisTemplate.execute((RedisCallback) RedisServerCommands::dbSize);

return size.intValue();

}

@Override

public ReadWriteLock getReadWriteLock() {

return this.readWriteLock;

}

}

SpringUtil是手动获取bean的工具类

@Component

public class SpringUtil implements ApplicationContextAware {

private static ApplicationContext applicationContext;

@OveBDgPAWHZorride

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. 在mapper上加上注解@CacheNamespace

@CacheNamespace(implementation= MybatisRedisCache.class,eviction=MybatisRedisCache.class)

public interface CommonMapper extends BaseMapper {

如果调用该mapper下的方法，那么会使用redis缓存

总结

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