Mybatis-Plus缓存
Mybatis-Plus是一个Mybatis框架的增强插件,根据官方描述,MP只做增强不做改变,引入它不会对现有工程产生影响,如丝般顺滑.并且只需简单配置,即可快速进行 CRUD 操作,从而节省大量时间.代码生成,分页,性能分析等功能一应俱全,3.X系列官方建议在service使用缓存，但是Service一般不用它，而是直接用@Cacheable， Mybatis-Plus缓存有一级缓存、二级缓存
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1. 介绍
1. Mybatis-Plus介绍
Mybatis-Plus是一个Mybatis框架的增强插件,根据官方描述,MP只做增强不做改变,引入它不会对现有工程产生影响,如丝般顺滑.并且只需简单配置,即可快速进行 CRUD 操作,从而节省大量时间.代码生成,分页,性能分析等功能一应俱全,3.X系列官方建议在service使用缓存，但是Service一般不用它，而是直接用@Cacheable
2. Mybatis-Plus缓存级别
缓存有一级缓存、二级缓存。
一级缓存是SqlSession级别的缓存。在操作数据库时需要构造sqlSession对象，在对象中有一个数据结构（HashMap）用于存储缓存数据。不同的sqlSession之间的缓存数据区域（HashMap）是互相不影响的。 一级缓存是默认开启的不用配置。
二级缓存是mapper级别的缓存，多个SqlSession去操作同一个Mapper的sql语句，多个SqlSession可以共用二级缓存，二级缓存是跨SqlSession的。二级缓存的开启（实体类必须序列化），然后在配置文件里面配置。
2. 代码
1. Pom依赖
...
<!--redis-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
<!--mybatis-plus依赖-->
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.3.2</version>
</dependency>
<!-- mysql依赖 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<!-- lombok -->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
...2. 配置文件中开启二级缓存
mybatis-plus:
mapper-locations: classpath*:/mapper/*.xml
call-setters-on-nulls: true
configuration:
#缓存开启
cache-enabled: true3. 工具类截图
包括：ApplicationContextUtil.java、MybatisPlusRedisCache.java、RedisConfig.java、RedisUtils.java
4. 工具类代码
1. 编写Redis工具类RedisUtils
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. 编写ApplicationContextUtil（手动获取bean）
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;
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
this.context = applicationContext;
}
/**
*
* @param beanName
* @return
*/
public static Object getBean(String beanName) {
return context.getBean(beanName);
}
}
3. 编写Mybatis-Plus缓存实现类MybatisRedisCache
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 javax.annotation.Resource;
import java.util.ArrayList;
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;
}
@Override
public String getId() {
return this.id;
}
@Override
public 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();
}
}
@Override
public 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;
}
@Override
public 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;
}
@Override
public 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();
}
}
@Override
public int getSize() {
if (redisUtil == null) {
getRedisUtil();//获取bean
}
Long size = (Long)redisUtil.execute((RedisCallback<Long>) RedisServerCommands::dbSize);
return size.intValue();
}
@Override
public 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;
}
}4. 编写RedisConfig配置类[注册redisTemplate和redisUtils工具]
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 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**/
@Bean
public 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jackson
template.setValueSerializer(jackson2JsonRedisSerializer);
// hash的value序列化方式采用jackson
template.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;
}
}5. 实体类代码
实体类一定要实现Serializable，以便序列化到redis中
@Data
@AllArgsConstructor
@NoArgsConstructor
public class TPatient implements Serializable {
@TableId(value = "id", type = IdType.AUTO)
private Integer id;
private String patientid;
private String cardNo;
private String myMobile;
/**
* 创建时间（LocaldateTime类型的字段需要加上两个注解才能顺利序列化）
*/
@JsonDeserialize(using = LocalDateTimeDeserializer.class)
@JsonSerialize(using = LocalDateTimeSerializer.class)
private LocalDateTime createTime;
....
}6. Mapper代码
在mapper类上加@CacheNamespace(implementation= MybatisPlusRedisCache.class,eviction=MybatisPlusRedisCache.class)
@Mapper
@CacheNamespace(implementation= MybatisPlusRedisCache.class,eviction=MybatisPlusRedisCache.class)
public interface PatientMapper extends BaseMapper<TPatient> {
//查询示例
List<TPatient> getPatientList(TPatient tPatient);
//保存示例
Integer savePatient(TPatient tPatient);
}7.XML代码
在<mapper>标签中加入代码<cache-ref namespace="mapper地址"/>
<?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.example.sc.thirdapp.h5.mapper.PatientMapper">
<cache-ref namespace="com.example.sc.thirdapp.h5.mapper.PatientMapper"/>
<!-- 保存示例 -->
<insert id="savePatient">
insert into t_patient(patientid,card_no) values(#{patientid},#{cardNo})
</insert>
<!-- 查询示例 -->
<select id="getPatientList" resultType="com.example.sc.thirdapp.h5.entity.TPatient">
select id,patientid,card_no
from t_patient
where my_mobile = #{myMobile}
</select>
</mapper>8. 测试
@SpringBootTest
@Slf4j
public class MapperTest {
@Resource
private PatientMapper patientMapper;
@Test
public void findTest(){
log.info("*****************************************************************************************");
TPatient tPatient=new TPatient();
tPatient.setMyMobile("123456");
List<TPatient> list=patientMapper.getPatientList(tPatient);
log.info("列表：{}",list.hashCode());
}
@Test
public void saveTest(){
log.info("*****************************************************************************************");
TPatient tPatient=new TPatient();
tPatient.setMyMobile("123456");
tPatient.setPatientid("1");
tPatient.setCardNo("1");
tPatient.setCardType("1");
tPatient.setCreateTime(LocalDateTime.now());
Integer result=patientMapper.savePatient(tPatient);
log.info("保存结果：{}",result);
}
}无缓存查询列表测试结果：先查询缓存，发现没有数据后查询数据、打印sql、存入缓存
已有缓存查询列表测试结果：先查询缓存，发现有数据，直接返回，不打印sql
保存示例测试结果：清理缓存
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