Question

spring在service层吧方法加上@cacheable注解，为什么还是每次跑数据库

Answer 1

没生效吧。启用缓存注解功能的配置加了吗，而且一定要声明在spring的主配置文件里，否则不会生效
<cache:annotation-driven cache-manager="cacheManager" />
<bean id="cacheManagerFactory" class="org.springframework.cache.ehcache.EhCacheManagerFactoryBean">
<property name="configLocation" value="classpath:cache/ehcache.xml"/>
</bean>

<bean id="cacheManager" class="org.springframework.cache.ehcache.EhCacheCacheManager">
<property name="cacheManager" ref="cacheManagerFactory"/>
</bean>