spring cache（三）集成demo

一、demo

1、pom

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>plus-cache-demo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.2.4</version>
        <relativePath/>
    </parent>


    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!--尽量不要同时导入mybatis 和 mybatis_plus，避免版本差异-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-spring-boot3-starter</artifactId>
            <version>3.5.5</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.13</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

        <!--cache-->
<!--        <dependency>-->
<!--            <groupId>org.springframework.boot</groupId>-->
<!--            <artifactId>spring-boot-starter-data-redis</artifactId>-->
<!--        </dependency>-->
<!--        <dependency>-->
<!--            <groupId>org.springframework.boot</groupId>-->
<!--            <artifactId>spring-boot-starter-data-redis-reactive</artifactId>-->
<!--        </dependency>-->

<!--        <dependency>-->
<!--            <groupId>org.springframework.boot</groupId>-->
<!--            <artifactId>spring-boot-starter-cache</artifactId>-->
<!--        </dependency>-->
        <!--spring-boot-starter-data-redis-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
        </dependency>

        <!--spring cache-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-cache</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-pool2</artifactId>
        </dependency>
    </dependencies>
</project>

2、配置文件

server.port=1111
server.servlet.context-path=/plusDemo
#mysql
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3308/demo?useUnicode=true&characterEncoding=utf-8&useSSL=false
spring.datasource.username=root
spring.datasource.password=wtyy
#mybatis
mybatis.mapper-locations=classpath*:mapper/*Mapper.xml
#打印日志
mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

#redis
spring.data.redis.host=127.0.0.1
spring.data.redis.port=6379
spring.data.redis.password=
spring.data.redis.lettuce.pool.max-active=8
spring.data.redis.lettuce.pool.max-wait=-1
spring.data.redis.lettuce.pool.max-idle=8
spring.data.redis.lettuce.pool.min-idle=0
spring.data.redis.lettuce.pool.enabled=true
spring.data.redis.lettuce.pool.time-between-eviction-runs=30s
#cache
#类型指定redis
spring.cache.type=redis
#一个小时，以毫秒为单位
spring.cache.redis.time-to-live=3600000
#给缓存的建都起一个前缀。  如果指定了前缀就用我们指定的，如果没有就默认使用缓存的名字作为前缀,一般不指定
#spring.cache.redis.key-prefix=CACHE_
#指定是否使用前缀
spring.cache.redis.use-key-prefix=true
#是否缓存空值，防止缓存穿透
spring.cache.redis.cache-null-values=true

3、config

package com.pluscache.demo.config;

import org.springframework.boot.autoconfigure.data.redis.RedisProperties;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.context.annotation.Configuration;

@Configuration
@EnableCaching
@EnableConfigurationProperties(RedisProperties.class)//开启属性绑定配置的功能
public class MyCacheConfig {
}

4、controller

package com.pluscache.demo.controller;

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.pluscache.demo.dto.ParamDTO;
import com.pluscache.demo.dto.UserDTO;
import com.pluscache.demo.service.ParamService;
import com.pluscache.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
@RequestMapping("/param")
public class ParamController {

    @Autowired
    private ParamService paramService;

    @RequestMapping("/listParams")
    public List<ParamDTO> listParams() {
        return paramService.listParams();
    }

    @RequestMapping("/addParam")
    public void addParam(ParamDTO paramDTO) {
         paramService.addParam(paramDTO);
    }

    @RequestMapping("/listParamsByKey")
    public List<ParamDTO> listParamsByKey(String key) {
        return paramService.listParamsByKey(key);
    }

    @RequestMapping("/deleteById")
    public void deleteById(String key) {
        paramService.deleteByKey(key);
    }

    @RequestMapping("/batchDeleteByKey")
    public void batchDeleteByKey(@RequestBody List<String> keys) {
        paramService.batchDeleteByKey(keys);
    }
}

5、service

package com.pluscache.demo.service.impl;

import com.pluscache.demo.dto.ParamDTO;
import com.pluscache.demo.repository.ParamRepository;
import com.pluscache.demo.service.ParamService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service("paramService")
public class ParamServiceImpl implements ParamService {

    @Autowired
    private ParamRepository paramRepository;

    @Override
    public List<ParamDTO> listParams() {
        return paramRepository.listParams();
    }

    @Override
    public void addParam(ParamDTO paramDTO) {
         paramRepository.addParam(paramDTO);
    }

    @Override
    public List<ParamDTO> listParamsByKey(String key) {
        return paramRepository.listParamsByKey(key);
    }

    @Override
    public void deleteByKey(String key) {
        paramRepository.deleteByKey(key);
    }

    @Override
    public void batchDeleteByKey(List<String> keys) {
        paramRepository.batchDeleteByKey(keys);
    }
}

6、dao

package com.pluscache.demo.repository;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.pluscache.demo.constant.DbConstant;
import com.pluscache.demo.dto.ParamDTO;
import com.pluscache.demo.dto.UserDTO;
import com.pluscache.demo.mapper.ParamMapper;
import com.pluscache.demo.mapper.UserMapper;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.CacheConfig;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Repository;

import java.util.List;

@Repository
@CacheConfig(cacheNames = {DbConstant.TABLE_PARAM_NAME_KEY_FORMAT})
@Slf4j
public class ParamRepository {

    @Autowired
    private ParamMapper paramMapper;

    //1、无参
    @Cacheable(key = "#root.methodName")
    public List<ParamDTO> listParams() {
        log.info("listParams无参start");
        LambdaQueryWrapper<ParamDTO> queryWrapper = new LambdaQueryWrapper<>();
        return paramMapper.selectList(queryWrapper);
    }

    @CacheEvict(key = "#root.methodName")
    public void addParam(ParamDTO paramDTO) {
        paramMapper.insert(paramDTO);
    }


    //2、单参
    @Cacheable(key = "{#p0}")
    public List<ParamDTO> listParamsByKey(String key) {
        log.info("listParamsByKey有参start");
        LambdaQueryWrapper<ParamDTO> queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper.eq(ParamDTO::getParamKey,key);
        return paramMapper.selectList(queryWrapper);
    }

    @CacheEvict(key = "{#p0}",beforeInvocation = true)
    public void deleteByKey(String key) {
        LambdaQueryWrapper<ParamDTO> queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper.eq(ParamDTO::getParamKey,key);
        paramMapper.delete(queryWrapper);
        int a = 1/0;
    }

    //3、集合参数
    //@CacheEvict(key = "@delKey.batchKeys(#p0)")
    //@CacheEvict(key = "@delKey.batchKeys(#p0?.![#this])")
    public void batchDeleteByKey(List<String> keys) {
        paramMapper.batchDeleteByKey(keys);
    }

}

package com.pluscache.demo.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.pluscache.demo.dto.ParamDTO;
import com.pluscache.demo.dto.UserDTO;
import org.apache.ibatis.annotations.Param;

import java.util.List;


public interface ParamMapper extends BaseMapper<ParamDTO> {

    void batchDeleteByKey(@Param("keys") List<String> keys);
}

7、dto与常量

package com.pluscache.demo.dto;

import com.baomidou.mybatisplus.annotation.TableName;
import lombok.Data;

import java.io.Serializable;


@Data
@TableName("t_param")
public class ParamDTO implements Serializable {
    private Integer id;
    private String paramKey;
    private String paramValue;
}

package com.pluscache.demo.constant;

public class DbConstant {
    public static final String TABLE_PARAM_NAME_KEY_FORMAT = "cache:t_param:";
}

8、测试：

8.1、无参

第一次访问localhost:1111/plusDemo/param/listParams控制台输出：

2024-04-25T17:14:33.330+08:00  INFO 36136 --- [nio-1111-exec-2] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Start completed.
JDBC Connection [HikariProxyConnection@644769222 wrapping com.mysql.cj.jdbc.ConnectionImpl@5ee5b9f5] will not be managed by Spring
==>  Preparing: SELECT id,param_key,param_value FROM t_param
==> Parameters: 
<==    Columns: id, param_key, param_value
<==        Row: 1, a, a_1
<==        Row: 2, a, a_2
<==      Total: 2
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@14369ce6]

再次访问，返回数据和第一次一样，但是控制台无输出，断点可以看到在serveimImpl直接返回了，并没有进入ParamRepository。查看redis:

8.2、单参

（1）缓存与删除缓存

访问localhost:1111/plusDemo/param/listParamsByKey?key=a

第一次走db查询，后面不走db查询。

查看redis:

key为t_param:::a：

value为：

访问localhost:1111/plusDemo/param/deleteById?key=a 刷新redis可以看到缓存已经被删除了

这时再访问listParamsByKey发现又走db层了

（2）删除缓存加入异常

 @CacheEvict(key = "{#p0}",beforeInvocation = true)
    public void deleteByKey(String key) {
        LambdaQueryWrapper<ParamDTO> queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper.eq(ParamDTO::getParamKey,key);
        paramMapper.delete(queryWrapper);
        int a = 1/0;
    }

访问localhost:1111/plusDemo/param/listParamsByKey?key=a后再访问localhost:1111/plusDemo/param/listParamsByKey?key=a可以看到缓存已经清除了，重新走db查询

如果没有写beforeInvocation = true，仍然走缓存查询，因为接口异常缓存没有被删除。

三、@CacheEvict自定义删除缓存

上述代码不支持批量删除缓存，再比如根据key模糊删除等也是不支持的，这种情况需要自定义删除方法。

1、原理：

@CacheEvict实际上是调用RedisCache的evict方法删除缓存的。所以需要重写该方法。

2、自定义处理

2.1、自定义RedisCache，重写evict方法

2.2、自定义RedisCacheManager，使用自定义的RedisCache

2.3、在RedisConfig中使用自定义的RedisCacheManager