SpringCache使用案例详解

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
    </dependency>
    <!--Mysql数据库驱动-->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>
    <!-- MyBatis-->
    <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus-boot-starter</artifactId>
        <version>3.4.0</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

@Data
public class User {
    private Long id;
    private String name;
    private Integer age;
}

@Mapper
public interface UserMapper extends BaseMapper<User> {
}

spring:
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
    username: root
    password: 123456
    driver-class-name: com.mysql.cj.jdbc.Driver
mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

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

@EnableCaching //开启缓存
@Configuration
public class CacheConfig {
    @Bean
    public CacheManager redisCacheManager(RedisConnectionFactory factory) {
        // 配置序列化（解决乱码的问题）,过期时间600秒
        RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig()
                //过期时间
                .entryTtl(Duration.ofSeconds(600))
                //缓存key
                .serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(new StringRedisSerializer()))
                //缓存组件value
                .serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(new GenericJackson2JsonRedisSerializer()))
                //value不为空,为空报错
                .disableCachingNullValues()
                .computePrefixWith(cacheName -> cacheName + ":");
        RedisCacheManager cacheManager = RedisCacheManager.builder(factory)
                .cacheDefaults(config)
                .build();
        return cacheManager;
    }
}

spring:
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
    username: root
    password: 123456
    driver-class-name: com.mysql.cj.jdbc.Driver
  redis:
    host: 127.0.0.1
    port: 6379
    password: 123456
mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

@RestController
@CacheConfig(cacheNames = "user", cacheManager = "redisCacheManager")
public class UserController {
    @Autowired
    UserMapper userMapper;
    @GetMapping("/list")
    @Cacheable(key = "#root.method.name")
    public List<User> list() {
        return userMapper.selectList(null);
    }
}
@RestController
@CacheConfig(cacheNames = "user", cacheManager = "redisCacheManager")
public class UserController {
    @Autowired
    UserMapper userMapper;
    @GetMapping("/list")
    @Cacheable(key = "#root.method.name")
    public List<User> list() {
        return userMapper.selectList(null);
    }
}

/**
 * 生成的缓存：myCache:qwer  value："9999"
 * condition = "#param.length() > 3" 参数长度大于3进行缓存
 * unless = "#result == null"        结果等于null不进行缓存
 */
@GetMapping("/getCachedValue")
@Cacheable(value = "myCache", key = "#param", condition = "#param.length() > 3", unless = "#result == null")
public String getCachedValue(@RequestParam("param") String param) {
    return "9999";
}

/**
 * 可以缓存null值，但会乱码，不影响使用
 * 缓存null值有两种情况：
 * 1.return null；
 * 2.方法返回值为void
 */
@GetMapping("/getUser")
@Cacheable(key = "#uid")
public User getUser(@RequestParam("uid") Long uid) {
    return userMapper.selectById(uid);
}

@GetMapping("/cacheEvict")
@CacheEvict(key = "'list'")//清除键为key的缓存
public void cacheEvict(){
}
@GetMapping("/cacheEvictAll")
@CacheEvict(key = "'user'", allEntries = true)//清除user分区下的所有缓存
public void cacheEvictAll() {
}

@GetMapping("/getUser")
@Cacheable(key = "#uid")
public User getUser(@RequestParam("uid") Long uid) {
    return userMapper.selectById(uid);
}
@GetMapping("/update")
@CachePut(key = "#uid")
public User update(@RequestParam("uid") Long uid) {
    User user = new User();
    user.setId(uid);
    user.setName("lisi9999");
    userMapper.updateById(user);
    return user;
}

/**
 * @Cacheable(key = "'allBooks'")：表示方法的返回值应该被缓存，使用 allBooks 作为缓存的键。
 * @CacheEvict(key = "#isbn")：表示在调用这个方法时，会清除缓存中键为 #isbn 的缓存项。
 * @CacheEvict(key = "'popularBooks'")：表示在调用这个方法时，会清除缓存中键为 'popularBooks' 的缓存项。
 */
@Caching(
        cacheable = @Cacheable(key = "'allBooks'"),
        evict = {
                @CacheEvict(key = "#isbn"),
                @CacheEvict(key = "'popularBooks'")
        }
)
public String updateBookByIsbn(String isbn, String newTitle) {
    System.out.println("Updating book in the database for ISBN: " + isbn);
    // Simulate updating data in a database
    return newTitle;
}

@CacheConfig(cacheNames = "user", cacheManager = "redisCacheManager")
public class UserCache {
}

@Transactional
@Cacheable(value = "myCache", key = "#id")
public String getCachedValueById(long id) {
    // 查询底层数据源，如果缓存中没有数据
    return fetchDataFromDataSource(id);
}