Spring Boot缓存实战 Caffeine示例

spring.cache.cache-names=foo,bar
spring.cache.caffeine.spec=maximumSize=500,expireAfterAccess=600s

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-cache</artifactId>
</dependency>
<dependency>
  <groupId>com.github.ben-manes.caffeine</groupId>
  <artifactId>caffeine</artifactId>
  <version>2.6.0</version>
</dependency>

@SpringBootApplication
@EnableCaching// 开启缓存，需要显示的指定
public class SpringBootStudentCacheCaffeineApplication {

  public static void main(String[] args) {
    SpringApplication.run(SpringBootStudentCacheCaffeineApplication.class, args);
  }
}

spring.cache.cache-names=people
spring.cache.caffeine.spec=initialCapacity=50,maximumSize=500,expireAfterWrite=10s,refreshAfterWrite=5s

/**
 * 必须要指定这个Bean，refreshAfterWrite=5s这个配置属性才生效
 *
 * @return
 */
@Bean
public CacheLoader<Object, Object> cacheLoader() {
  CacheLoader<Object, Object> cacheLoader = new CacheLoader<Object, Object>() {

    @Override
    public Object load(Object key) throws Exception {
      return null;
    }

    // 重写这个方法将oldValue值返回回去，进而刷新缓存
    @Override
    public Object reload(Object key, Object oldValue) throws Exception {
      return oldValue;
    }
  };
  return cacheLoader;
}

/**
 * @author yuhao.wang
 */
@Service
public class PersonServiceImpl implements PersonService {
  private static final Logger logger = LoggerFactory.getLogger(PersonServiceImpl.class);

  @Autowired
  PersonRepository personRepository;

  @Override
  @CachePut(value = "people", key = "#person.id")
  public Person save(Person person) {
    Person p = personRepository.save(person);
    logger.info("为id、key为:" + p.getId() + "数据做了缓存");
    return p;
  }

  @Override
  @CacheEvict(value = "people")//2
  public void remove(Long id) {
    logger.info("删除了id、key为" + id + "的数据缓存");
    //这里不做实际删除操作
  }

  /**
   * Cacheable
   * value：缓存key的前缀。
   * key：缓存key的后缀。
   * sync：设置如果缓存过期是不是只放一个请求去请求数据库，其他请求阻塞，默认是false。
   */
  @Override
  @Cacheable(value = "people", key = "#person.id", sync = true)
  public Person findOne(Person person, String a, String[] b, List<Long> c) {
    Person p = personRepository.findOne(person.getId());
    logger.info("为id、key为:" + p.getId() + "数据做了缓存");
    return p;
  }

  @Override
  @Cacheable(value = "people1")//3
  public Person findOne1() {
    Person p = personRepository.findOne(2L);
    logger.info("为id、key为:" + p.getId() + "数据做了缓存");
    return p;
  }

  @Override
  @Cacheable(value = "people2")//3
  public Person findOne2(Person person) {
    Person p = personRepository.findOne(person.getId());
    logger.info("为id、key为:" + p.getId() + "数据做了缓存");
    return p;
  }
}