spring緩存cache的使用

在spring配置文件中添加schema和spring對緩存注解的支持：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
     xmlns:aop="http://www.springframework.org/schema/aop"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns:mvc="http://www.springframework.org/schema/mvc"
     xmlns:context="http://www.springframework.org/schema/context"
     xmlns:tx="http://www.springframework.org/schema/tx"
     xmlns:p="http://www.springframework.org/schema/p"
     xmlns:cache="http://www.springframework.org/schema/cache"
     xsi:schemaLocation="http://www.springframework.org/schema/beans
          http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
          http://www.springframework.org/schema/context
          http://www.springframework.org/schema/context/spring-context-3.0.xsd
         http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
          http://www.springframework.org/schema/aop
          http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
          http://www.springframework.org/schema/tx
          http://www.springframework.org/schema/tx/spring-tx.xsd
          http://www.springframework.org/schema/cache
          http://www.springframework.org/schema/cache/spring-cache.xsd"
     default-autowire="byName">
  <!--緩存配置-->
  <cache:annotation-driven/>

在spring配置文件中加入緩存管理器：

  <!-- generic cache manager -->
  <bean id="cacheManager"
        class="org.springframework.cache.support.SimpleCacheManager">
      <property name="caches">
          <set>
              <bean class="org.springframework.cache.concurrent.ConcurrentMapCacheFactoryBean"
                    p:name="hardwareCache"/>
                    <bean class="org.springframework.cache.concurrent.ConcurrentMapCacheFactoryBean" 
                    p:name="bannerCache"/>
          </set>
      </property>
  </bean>

然后在代碼的service的impl層加上如下注解即可把數據緩存起來：

@Cacheable(value="bannerCache")

其中@Cacheable表示spring將緩存該方法獲取到的數據，(緩存是基于key-value方式實現的)，key為該方法的參數，value為返回的數據，當你連續訪問該方法時你會發現只有第一次會訪問數據庫. 其他次數只是查詢緩存.減輕了數據庫的壓力.

當更新了數據庫的數據，需要讓緩存失效時，使用下面的注解：

這個注解表示讓appCache緩存的所有數據都失效。

@CacheEvict(value = "appCache", allEntries = true)

springcache配置緩存存活時間

Spring Cache @Cacheable本身不支持key expiration的設置，以下代碼可自定義實現Spring Cache的expiration，針對Redis、SpringBoot2.0。

直接上代碼：

@Service
@Configuration
public class CustomCacheMng{
  private Logger logger = LoggerFactory.getLogger(this.getClass());
  // 指明自定義cacheManager的bean name
  @Cacheable(value = "test",key = "'obj1'",cacheManager = "customCacheManager")
  public User cache1(){
      User user = new User().setId(1);
      logger.info("1");
      return user;
  }
  @Cacheable(value = "test",key = "'obj2'")
  public User cache2(){
      User user = new User().setId(1);
      logger.info("2");
      return user;
  }
  
  // 自定義的cacheManager，實現存活2天
  @Bean(name = "customCacheManager")
  public CacheManager cacheManager(
          RedisTemplate<?, ?> redisTemplate) {
      RedisCacheWriter writer = RedisCacheWriter.lockingRedisCacheWriter(redisTemplate.getConnectionFactory());
      RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig().entryTtl(Duration.ofDays(2));
      return new RedisCacheManager(writer, config);
  }
  
  // 提供默認的cacheManager，應用于全局
  @Bean
  @Primary
  public CacheManager defaultCacheManager(
          RedisTemplate<?, ?> redisTemplate) {
      RedisCacheWriter writer = RedisCacheWriter.lockingRedisCacheWriter(redisTemplate.getConnectionFactory());
      RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig();
      return new RedisCacheManager(writer, config);
  }
}

以上為個人經驗，希望能給大家一個參考，也希望大家多多支持服務器之家。

原文鏈接：https://blog.csdn.net/Petershusheng/article/details/52397895