hibernate执行计划缓存造成内存泄露
<property name="hibernate.query.plan_cache_max_size">64</property>
<property name="hibernate.query.plan_parameter_metadata_max_size">32</property>
<property name="hibernate.query.plan_cache_max_soft_references">1024</property>
<property name="hibernate.query.plan_cache_max_strong_references">64</property>