SpringBoot下使用redis缓存机制

案例的目的是: 在用户第一次访问时进行mysql查询，然后将该条数据缓存到redis中，后续的查询都直接在redis中进行缓存查询， 并且在进行修改操作后及时将redis中的数据进行更新

用到的工具： navicat 、RedisDesktopManager、Idea 、Postman

1.导入依赖

<!--redis缓存--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-cache</artifactId> </dependency> <!--redis启动器--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-redis</artifactId> </dependency> <!--web--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <!--mysql驱动--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.47</version> <scope>runtime</scope> </dependency> <!--myBatisPlus--> <dependency> <groupId>com.baomidou</groupId> <artifactId>mybatis-plus-boot-starter</artifactId> <version>3.4.0</version> </dependency> <!--lombok--> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </dependency>

2.配置数据库

application.properties

# mysql配置 spring.datasource.url=jdbc:mysql:///temporary?characterEncoding=utf-8&useSSL=false spring.datasource.driver-class-name=com.mysql.jdbc.Driver spring.datasource.username=root spring.datasource.password=12345 #redis配置 spring.redis.host=172.16.2.134 spring.redis.port=6379 spring.redis.password=123456 spring.redis.database=1 #日志配置 mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

3.数据库准备

使用navicat连接mySql 使用RedisDesktopManager连接redis

4.实体类 mapper接口 service controller生成

Student

@Data public class Student implements Serializable { private static final long serialVersionUID = 1L; @TableId(value = "id", type = IdType.AUTO) private Integer id; private String name; private String sSex; }

StudentMapper

public interface StudentMapper extends BaseMapper<Student> { }

StudentService

public interface StudentService extends IService<Student> { Student getById(Integer id); Student update(Student student); }

StudentServiceImpl

@Service public class StudentServiceImpl extends ServiceImpl<StudentMapper, Student> implements StudentService { @Cacheable(value = "Student",key = "args[0]") @Override public Student getById(Integer id) { return baseMapper.selectById(id); } @CachePut(value = "Student",key = "args[0].id") @Override public Student update(Student student) { baseMapper.updateById(student); return student; } }

StudentController

@RestController public class StudentController { @Autowired private StudentService studentService; @GetMapping("/demo3/{a}") public Student m3(@PathVariable("a") Integer a){ return studentService.getById(a); } @PostMapping("/demo4") public Student m4(@RequestBody Student student){ System.out.println(student); return studentService.update(student); } }

5.运行程序后的结果

进行查询 向数据库发送了请求

第二次进行访问 语句没有变化

redis中存储状况： 可以看到redis中自动存放了数据，但是value值是序列化后的数据，不利于解读，文章最后再说解决方案

进行修改 使用postman发送post请求

发送了更新的语句 redis中变化： 可以看到最后的几个字符是不一致的

浏览器中访问： 信息已经发生变化

6. redis中的序列化解决

定义一个配置类，加上@Configuration注入到容器中即可

@Configuration public class MyRedisConfig { @Bean public RedisCacheConfiguration cacheConfiguration(){ DefaultFormattingConversionService conversionService = new DefaultFormattingConversionService(); registerDefaultConverters(conversionService); RedisCacheConfiguration configuration = RedisCacheConfiguration.defaultCacheConfig() .serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(RedisSerializer.string())) .serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(RedisSerializer.json())) .withConversionService(conversionService) .entryTtl(Duration.ZERO) .computePrefixWith(CacheKeyPrefix.simple()); return configuration; } }

重启后显示结果：

7.缓存注解总结

项目开启缓存，在主配置类上加@EnableCaching@Cacheable是表明该方法需要开启缓存,可以指定value即数据缓存存在包名，key属性指定存储时key值@CachePut(value = "Student",key = "args[0].id")指定该方法进行更新操作后将数据在redis内存中也进行更新@CacheEvict表示进行数据删除时对redis内存中数据也进行删除@CacheXX内key设置支持表达式设置，具体参见：Spring缓存注解@Cacheable