系列十、SpringBoot + MyBatis + Redis实现分布式缓存（基于注解方式）

一、概述

上篇文章系列九、SpringBoot + MyBatis + Redis实现分布式缓存介绍了基于xml方式实现分布式缓存的效果，当前大家使用的技术栈基本是springboot+各种框架的组合，而springboot显著的一个特点就是去xml配置，那么在无xml配置的情形下，又该如何实现分布式缓存呢？请看下面的代码实战

二、代码实战

2.1、分布式缓存相关的注解

基于注解方式的分布式缓存，主要涉及到如下几个注解：

（1）@EnableCaching：一般标注在配置类上，表示开启Spring的缓存，如果不加此注解的话Spring自带的缓存将不生效；

（2）@CacheConfig(cacheNames = "xxx")：一般标注在service类上，用于配置cache的名字，建议以当前service类的全路径名作为cache的名字；

（3）@Cacheable：一般标识在service层的查询方法上，表示将一个方法的返回值缓存起来，默认情况下，缓存的key就是方法的参数，缓存的value就是方法的返回值,如果查询方法无参数，则会使用默认的key，即SimpleKey []；

（4）@CachePut(key = "#department.id")：一般加在service层的更新方法上（update）,当数据库中的数据更新后，缓存中的数据也要跟着更新，使用此注解，可以将方法的返回值自动更新到已经存在的key上

（5）@CacheEvict：一般加在service层的删除方法上，当数据库中的数据删除后，相关的缓存也会被删除，使用该注解的时候，也可以配置按照某种条件删除（某种条件：@CacheEvict注解中的条件，例如：value、cacheNames、key、keyGenerator...）

2.2、项目概览

2.3、pom

<dependencies><!-- springboot --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-devtools</artifactId></dependency><!-- 数据源 --><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.26</version></dependency><dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>2.3.1</version></dependency><dependency><groupId>com.alibaba</groupId><artifactId>druid-spring-boot-starter</artifactId><version>1.1.10</version></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId></dependency><!-- 工具 --><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.30</version></dependency><dependency><groupId>cn.hutool</groupId><artifactId>hutool-all</artifactId><version>5.8.21</version></dependency><dependency><groupId>org.apache.commons</groupId><artifactId>commons-lang3</artifactId></dependency><dependency><groupId>org.apache.commons</groupId><artifactId>commons-collections4</artifactId><version>4.4</version></dependency><dependency><groupId>com.alibaba.fastjson2</groupId><artifactId>fastjson2</artifactId><version>2.0.25</version></dependency></dependencies>

2.4、yml

server:port: 9999spring:redis:host: port: 6379database: 0password: 123456datasource:type: com.alibaba.druid.pool.DruidDataSourcedriver-class-name: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://localhost:3306/20231018_redis?useSSL=false&useUnicode=true&characterEncoding=UTF8&serverTimezone=GMTusername: rootpassword: 123456mybatis:mapper-locations: classpath:mapper/*.xmltype-aliases-package: org.stat.entity.modelconfiguration:map-underscore-to-camel-case: truelogging:level:org:star:mapper: debug

2.5、主启动

/*** @Author : 一叶浮萍归大海* @Date: 2023/12/10 12:44* @Description:**/
@MapperScan(basePackages = "org.star.mapper")
@SpringBootApplication
public class SpringbootRedisDistributeCacheAnnotationApplication {public static void main(String[] args) {SpringApplication.run(SpringbootRedisDistributeCacheAnnotationApplication.class, args);}}

2.6、MyRedisConfig

/*** @Author : 一叶浮萍归大海* @Date: 2023/12/10 15:28* @Description:* @EnableCaching的作用：开启Spring的缓存，如果不加此注解的话Spring自带的缓存将不生效**/
@EnableCaching
@Configuration
public class MyRedisConfig {/*** RedisTemplate k v 序列化** @param connectionFactory* @return*/@Beanpublic RedisTemplate<Object, Object> redisTemplate(LettuceConnectionFactory connectionFactory) {RedisTemplate<Object, Object> redisTemplate = new RedisTemplate<>();redisTemplate.setConnectionFactory(connectionFactory);redisTemplate.setKeySerializer(RedisSerializer.string());redisTemplate.setValueSerializer(new GenericJackson2JsonRedisSerializer());redisTemplate.setHashKeySerializer(RedisSerializer.string());redisTemplate.setHashValueSerializer(new GenericJackson2JsonRedisSerializer());redisTemplate.afterPropertiesSet();return redisTemplate;}@Beanpublic RedisCacheManager redisCacheManager(RedisTemplate redisTemplate) {RedisCacheWriter redisCacheWriter = RedisCacheWriter.nonLockingRedisCacheWriter(redisTemplate.getConnectionFactory());RedisCacheConfiguration redisCacheConfiguration = RedisCacheConfiguration.defaultCacheConfig()// 设置默认的超时时间为2小时.entryTtl(Duration.ofHours(2)).serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(redisTemplate.getValueSerializer()))// 设置默认的缓存前缀.prefixCacheNameWith("REDIS_CACHE_");return new RedisCacheManager(redisCacheWriter, redisCacheConfiguration);}}

2.7、DepartmentDO

/*** @Author : 一叶浮萍归大海* @Date: 2023/12/10 12:48* @Description:*/
@Data
@AllArgsConstructor
@NoArgsConstructor
@Accessors(chain = true)
@ToString(callSuper = true)
public class DepartmentDO implements Serializable {/*** 编号*/private Integer id;/*** 部门名称*/private String departmentName;}

2.8、DepartmentMapper.java

/*** @Author : 一叶浮萍归大海* @Date: 2023/12/10 12:50* @Description:*/
public interface DepartmentMapper {/*** 查询所有部门* @return*/List<DepartmentDO> listAllDepartment();/*** 根据id查询部门信息* @param id* @return*/DepartmentDO getDepartmentById(Integer id);/*** 根据id和departmentName查询部门* @param id* @param departmentName* @return*/DepartmentDO getDepartment(Integer id,String departmentName);/*** 更新Department* @param department* @return*/int updateDepartment(DepartmentDO department);/*** 删除部门* @param id*/void deleteDepartment(Integer id);
}

2.9、DepartmentMapper.xml

<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="org.star.mapper.DepartmentMapper"><select id="listAllDepartment" resultType="org.star.entity.model.DepartmentDO">select id,department_name from department</select><select id="getDepartmentById" resultType="org.star.entity.model.DepartmentDO">select id,department_name from department where id = #{id}</select><select id="getDepartment" resultType="org.star.entity.model.DepartmentDO">select id,department_name from department where id = #{id} and department_name = #{departmentName}</select><update id="updateDepartment" useGeneratedKeys="true" keyProperty="id">update department set department_name = #{departmentName} where id = #{id}<selectKey resultType="org.star.entity.model.DepartmentDO" order="AFTER" keyProperty="id">select id,department_name from department where id = #{id}</selectKey></update><delete id="deleteDepartment">delete from department where id = #{id}</delete></mapper>

2.10、DepartmentService

/*** @Author : 一叶浮萍归大海* @Date: 2023/12/10 20:00* @Description:* 基于注解的分布式缓存，redis中key的生成规则：${prefixCacheNameWith} + "_" + ${cacheNames} + "_" + ${key}*      说明：prefixCacheNameWith为RedisCacheManager中配置的前缀*      举例：*          （1）listAllDepartment ===> REDIS_CACHE_org.star.service.DepartmentService::SimpleKey []*          （2）getDepartmentById ===> REDIS_CACHE_org.star.service.DepartmentService::1*          （3）getDepartment ===> REDIS_CACHE_org.star.service.DepartmentService::SimpleKey [1,研发部]**/
@Service
@CacheConfig(cacheNames = "org.star.service.DepartmentService")
public class DepartmentService {@Resourceprivate DepartmentMapper departmentMapper;/*** @return* @Cacheable的作用：*      @Cacheable注解一般加在查询方法上，表示将一个方法的返回值缓存起来，* 默认情况下，缓存的key就是方法的参数，缓存的value就是方法的返回值,如果查询* 方法无参数，则会使用默认的key，即SimpleKey []*/@Cacheablepublic List<DepartmentDO> listAllDepartment() {List<DepartmentDO> departments = departmentMapper.listAllDepartment();return departments;}/*** 对于只有一个参数的查询方法，其key位id对应的值* @param id* @return*/@Cacheablepublic DepartmentDO getDepartmentById(Integer id) {return departmentMapper.getDepartmentById(id);}/**** 对于有多个参数的查询方法，其key为所有的参数，如果想修改，可以单独指定，例如：@Cacheable(key = "#id")* @param id* @param departmentName* @return*/@Cacheablepublic DepartmentDO getDepartment(Integer id,String departmentName) {return departmentMapper.getDepartment(id,departmentName);}/*** @CachePut作用：*      @CachePut注解一般加在更新方法上（update）,当数据库中的数据更新后，缓存中的数据也要跟着更新，使用此注解，可以将方法的返回值*      自动更新到已经存在的key上，示例如下：* @param department* @return*/@CachePut(key = "#department.id")public DepartmentDO updateDepartment(DepartmentDO department) {departmentMapper.updateDepartment(department);return department;}/*** @CacheEvict()作用：*      @CacheEvict()注解一般加在删除方法上，当数据库中的数据删除后，相关的缓存也会被删除，使用该注解的时候，也可以配置按照某种条件*      删除（某种条件：@CacheEvict注解中的条件，例如：value、cacheNames、key、keyGenerator...）* @param id*/@CacheEvictpublic void deleteDepartment(Integer id) {departmentMapper.deleteDepartment(id);}}

2.11、DepartmentServiceTest

/*** @Author : 一叶浮萍归大海* @Date: 2023/12/10 20:07* @Description:*/
@SpringBootTest
public class DepartmentServiceTest {@Resourceprivate DepartmentService departmentService;@Testpublic void listAllDepartmentTest() {List<DepartmentDO> departments1 = departmentService.listAllDepartment();System.out.println("departments1 = " + departments1);System.out.println("=============================");List<DepartmentDO> departments2 = departmentService.listAllDepartment();System.out.println("departments2 = " + departments2);}@Testpublic void getDepartmentByIdTest() {DepartmentDO department1 = departmentService.getDepartmentById(1);System.out.println("department1 = " + department1);System.out.println("========================");DepartmentDO department2 = departmentService.getDepartmentById(1);System.out.println("department2 = " + department2);}@Testpublic void getDepartmentTest() {DepartmentDO department1 = departmentService.getDepartment(1, "研发部");System.out.println("department1 = " + department1);System.out.println("============================");DepartmentDO department2 = departmentService.getDepartment(1, "研发部");System.out.println("department2 = " + department2);}@Testpublic void updateDepartmentTest() {DepartmentDO department = new DepartmentDO().setDepartmentName("研发部444").setId(1);DepartmentDO updatedDepartment = departmentService.updateDepartment(department);System.out.println("updatedDepartment = " + updatedDepartment);}@Testpublic void deleteDepartmentTest() {departmentService.deleteDepartment(1);}}