一、准备工作

1.Redis工具类

import org.springframework.data.redis.core.RedisCallback;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.util.CollectionUtils;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.TimeUnit;/*** Redis工具类,一般企业开发常用的一个工具类，不会去用原生的redis配置类*/public final class RedisUtils {private RedisTemplate<String, Object> redisTemplate;public RedisUtils(RedisTemplate<String, Object> redisTemplate) {this.redisTemplate = redisTemplate;}public Object execute(RedisCallback action) {Object execute = redisTemplate.execute(action);return execute;}/*** 删除Collection<String>集合中的key** @param keys* @return*/public Long del(Collection<String> keys) {Long delete = redisTemplate.delete(keys);return delete;}/*** 模糊查询key** @param str 模糊查询的条件* @return*/public Set<String> keys(String str) {Set<String> keys = redisTemplate.keys(str);return keys;}/*** 消息订阅与发布：发布** @param channel* @param message*/public void convertAndSend(String channel, Object message) {redisTemplate.convertAndSend(channel, message);}/*** 如果不存在且保存的时间大于0即可创建成功，否则创建失败** @param key   键* @param value 值* @param time  缓存的时间* @return*/public boolean setNx(String key, Object value, long time) {try {if (time > 0) {return redisTemplate.opsForValue().setIfAbsent(key, value, time, TimeUnit.SECONDS);} else {return false;}} catch (Exception e) {e.printStackTrace();return false;}}/*** 如果不存在才创建成功，否则就创建失败** @param key* @param value* @return*/public boolean setNx(String key, Object value) {try {return redisTemplate.opsForValue().setIfAbsent(key, value);} catch (Exception e) {e.printStackTrace();return false;}}// =============================common============================public boolean expire(String key, long time) {try {if (time > 0) {redisTemplate.expire(key, time, TimeUnit.SECONDS);}return true;} catch (Exception e) {e.printStackTrace();return false;}}public long getExpire(String key) {return redisTemplate.getExpire(key, TimeUnit.SECONDS);}public boolean hasKey(String key) {try {return redisTemplate.hasKey(key);} catch (Exception e) {e.printStackTrace();return false;}}public void del(String... key) {if (key != null && key.length > 0) {if (key.length == 1) {redisTemplate.delete(key[0]);} else {redisTemplate.delete((Collection<String>) CollectionUtils.arrayToList(key));}}}// ============================String=============================public Object get(String key) {return key == null ? null : redisTemplate.opsForValue().get(key);}public boolean set(String key, Object value) {try {redisTemplate.opsForValue().set(key, value);return true;} catch (Exception e) {e.printStackTrace();return false;}}public boolean set(String key, Object value, long time) {try {if (time > 0) {redisTemplate.opsForValue().set(key, value, time, TimeUnit.SECONDS);} else {set(key, value);}return true;} catch (Exception e) {e.printStackTrace();return false;}}public long incr(String key, long delta) {if (delta < 0) {throw new RuntimeException("递增因子必须大于0");}return redisTemplate.opsForValue().increment(key, delta);}public long decr(String key, long delta) {if (delta < 0) {throw new RuntimeException("递减因子必须大于0");}return redisTemplate.opsForValue().increment(key, -delta);}// ================================Map=================================public Object hget(String key, String item) {return redisTemplate.opsForHash().get(key, item);}public Map<Object, Object> hmget(String key) {return redisTemplate.opsForHash().entries(key);}public boolean hmset(String key, Map<String, Object> map) {try {redisTemplate.opsForHash().putAll(key, map);return true;} catch (Exception e) {e.printStackTrace();return false;}}public boolean hmset(String key, Map<String, Object> map, long time) {try {redisTemplate.opsForHash().putAll(key, map);if (time > 0) {expire(key, time);}return true;} catch (Exception e) {e.printStackTrace();return false;}}public boolean hset(String key, String item, Object value) {try {redisTemplate.opsForHash().put(key, item, value);return true;} catch (Exception e) {e.printStackTrace();return false;}}public boolean hset(String key, String item, Object value, long time) {try {redisTemplate.opsForHash().put(key, item, value);if (time > 0) {expire(key, time);}return true;} catch (Exception e) {e.printStackTrace();return false;}}public void hdel(String key, Object... item) {redisTemplate.opsForHash().delete(key, item);}public boolean hHasKey(String key, String item) {return redisTemplate.opsForHash().hasKey(key, item);}public double hincr(String key, String item, double by) {return redisTemplate.opsForHash().increment(key, item, by);}public double hdecr(String key, String item, double by) {return redisTemplate.opsForHash().increment(key, item, -by);}// ============================set=============================public Set<Object> sGet(String key) {try {return redisTemplate.opsForSet().members(key);} catch (Exception e) {e.printStackTrace();return null;}}public boolean sHasKey(String key, Object value) {try {return redisTemplate.opsForSet().isMember(key, value);} catch (Exception e) {e.printStackTrace();return false;}}public long sSet(String key, Object... values) {try {return redisTemplate.opsForSet().add(key, values);} catch (Exception e) {e.printStackTrace();return 0;}}public long sSetAndTime(String key, long time, Object... values) {try {Long count = redisTemplate.opsForSet().add(key, values);if (time > 0) {expire(key, time);}return count;} catch (Exception e) {e.printStackTrace();return 0;}}public long sGetSetSize(String key) {try {return redisTemplate.opsForSet().size(key);} catch (Exception e) {e.printStackTrace();return 0;}}public long setRemove(String key, Object... values) {try {Long count = redisTemplate.opsForSet().remove(key, values);return count;} catch (Exception e) {e.printStackTrace();return 0;}}// ===============================list=================================public List<Object> lGet(String key, long start, long end) {try {return redisTemplate.opsForList().range(key, start, end);} catch (Exception e) {e.printStackTrace();return null;}}public long lGetListSize(String key) {try {return redisTemplate.opsForList().size(key);} catch (Exception e) {e.printStackTrace();return 0;}}public Object lGetIndex(String key, long index) {try {return redisTemplate.opsForList().index(key, index);} catch (Exception e) {e.printStackTrace();return null;}}public boolean lSet(String key, Object value) {try {redisTemplate.opsForList().rightPush(key, value);return true;} catch (Exception e) {e.printStackTrace();return false;}}public boolean lSet(String key, Object value, long time) {try {redisTemplate.opsForList().rightPush(key, value);if (time > 0) {expire(key, time);}return true;} catch (Exception e) {e.printStackTrace();return false;}}public boolean lSet(String key, List<Object> value) {try {redisTemplate.opsForList().rightPushAll(key, value);return true;} catch (Exception e) {e.printStackTrace();return false;}}public boolean lSet(String key, List<Object> value, long time) {try {redisTemplate.opsForList().rightPushAll(key, value);if (time > 0) {expire(key, time);}return true;} catch (Exception e) {e.printStackTrace();return false;}}public boolean lUpdateIndex(String key, long index, Object value) {try {redisTemplate.opsForList().set(key, index, value);return true;} catch (Exception e) {e.printStackTrace();return false;}}public long lRemove(String key, long count, Object value) {try {Long remove = redisTemplate.opsForList().remove(key, count, value);return remove;} catch (Exception e) {e.printStackTrace();return 0;}}
}

2.Redis配置模版

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.jsontype.impl.LaissezFaireSubTypeValidator;
import com.newbniz.newbbs.utils.RedisUtils;
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;@Configuration
@Slf4j
public class RedisConfig {/*** redis配置模板**/@Beanpublic RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) {//为了开发的方便，一般直接使用<String, Object>RedisTemplate<String, Object> template = new RedisTemplate<>();template.setConnectionFactory(factory);//json的序列化配置Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);ObjectMapper om = new ObjectMapper();om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);om.activateDefaultTyping(LaissezFaireSubTypeValidator.instance,ObjectMapper.DefaultTyping.NON_FINAL,JsonTypeInfo.As.PROPERTY);jackson2JsonRedisSerializer.setObjectMapper(om);//String的序列化StringRedisSerializer stringRedisSerializer = new StringRedisSerializer();// key采用String的序列化方式template.setKeySerializer(stringRedisSerializer);// hash的key也采用String的序列化方式template.setHashKeySerializer(stringRedisSerializer);// value序列化方式采用jacksontemplate.setValueSerializer(jackson2JsonRedisSerializer);// hash的value序列化方式采用jacksontemplate.setHashValueSerializer(jackson2JsonRedisSerializer);template.afterPropertiesSet();return template;}@Bean(name = "redisUtils")public RedisUtils redisUtils(final RedisTemplate<String, Object> redisTemplate) {final RedisUtils jedisService = new RedisUtils(redisTemplate);return jedisService;}}

3.手动获取bean的工具类

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;/*** @ClassName : ApplicationContextUtil* @Description : 手动获取bean的工具类*/
@Component
public class ApplicationContextUtil implements ApplicationContextAware {private static ApplicationContext context;/*** @param beanName* @return*/public static Object getBean(String beanName) {return context.getBean(beanName);}@Overridepublic void setApplicationContext(ApplicationContext applicationContext) throws BeansException {this.context = applicationContext;}
}

二、Mybatis Plus结合Redis实现缓存

1.自定义缓存管理类

package com.newbniz.newbbs.utils;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.util.DigestUtils;import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;/*** @ClassName : MybatisRedisCache* @Description : mybatis-plus结合redis自定义缓存管理* @author ZJ*/
@Slf4j
public class MybatisPlusRedisCache implements Cache {/*** 注意，这里无法通过@Autowired等注解的方式注入bean,只能手动获取*/private RedisUtils redisUtil;/*** 手动获取bean** @return*/private void getRedisUtil() {redisUtil = (RedisUtils) ApplicationContextUtil.getBean("redisUtils");}// 读写锁private final ReadWriteLock readWriteLock = new ReentrantReadWriteLock(true);private String id;public MybatisPlusRedisCache(final String id) {if (id == null) {throw new IllegalArgumentException("Cache instances require an ID");}log.info("二级缓存id：{}",id);this.id = id;}@Overridepublic String getId() {return this.id;}@Overridepublic void putObject(Object key, Object value) {log.info("存入缓存");if (redisUtil == null) {getRedisUtil();//获取bean}try {//将key加密后存入redisUtil.hset(this.id,this.MD5Encrypt(key),value);} catch (Exception e) {log.error("存入缓存失败！");e.printStackTrace();}}@Overridepublic Object getObject(Object key) {log.info("获取缓存");if (redisUtil == null) {getRedisUtil();//获取bean}try {if (key != null) {return redisUtil.hget(this.id,this.MD5Encrypt(key));}} catch (Exception e) {log.error("获取缓存失败！");e.printStackTrace();}return null;}@Overridepublic Object removeObject(Object key) {log.info("删除缓存");if (redisUtil == null) {getRedisUtil();//获取bean}try {if (key != null) {redisUtil.del(this.MD5Encrypt(key));}} catch (Exception e) {log.error("删除缓存失败！");e.printStackTrace();}return null;}@Overridepublic void clear() {log.info("清空缓存");if (redisUtil == null) {getRedisUtil();//获取bean}try {redisUtil.del(this.id);} catch (Exception e) {log.error("清空缓存失败！");e.printStackTrace();}}@Overridepublic int getSize() {if (redisUtil == null) {getRedisUtil();//获取bean}Long size = (Long)redisUtil.execute((RedisCallback<Long>) RedisServerCommands::dbSize);return size.intValue();}@Overridepublic ReadWriteLock getReadWriteLock() {return this.readWriteLock;}/*** MD5加密存储key,以节约内存*/private String MD5Encrypt(Object key){String s = DigestUtils.md5DigestAsHex(key.toString().getBytes());return s;}}

2.Mapper类加注解

@Repository
//对需要缓存的加注解
//下面这个↓
@CacheNamespace(implementation= MybatisPlusRedisCache.class,eviction=MybatisPlusRedisCache.class)
public interface xxxxxMapper extends BaseMapper<ForumArticle> {}

3.Mapper.xml文件开启二级缓存

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.newbniz.newbbs.mapper.XxxxMapper"><!-- 注意namespace  --><!-- 下面这个 ↓ ↓ ↓ ，不加则不开启二级缓存  --><cache-ref namespace="com.newbniz.newbbs.mapper.XxxxMapper"/>
</mapper>