Hibernate second level cache example

问题

I am developing hibernate + ehcache program.

@Entity
@Table(name = "pizza")
public class Pizza implements Serializable{
    @Id
    @GeneratedValue
    private Integer id;
    private String name;
    private double price;

    public long getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

}

ehcache.xml

  <cache name="com.abp.osp.domain.Pizza"   
maxElementsInMemory="100"   
eternal="false"   
timeToIdleSeconds="5"   
timeToLiveSeconds="200" /> 
</ehcache>

I have mentioned ehcache in bean.xml

   <prop key="hibernate.cache.provider_configuration_file_resource_path">ehcache.xml</prop>
        <prop key="hibernate.cache.use_second_level_cache">true</prop>
        <prop key="hibernate.cache.use_query_cache">true</prop>
        <prop key="hibernate.cache.region.factory_class">net.sf.ehcache.hibernate.EhCacheRegionFactory</prop>
         <prop key="hibernate.cache.provider_class">net.sf.ehcache.hibernate.EhCacheProvider</prop>

and my calling method within dao class is

 Session session1=sessionFactory.openSession();  

          Pizza pizza2=(Pizza)session1.load(Pizza.class, 2);
          System.out.println("pizza2--"+pizza2.getName());  
          session1.close(); 

 Session session2=sessionFactory.openSession();  

          Pizza pizza4=(Pizza)session2.load(Pizza.class, 2);
          System.out.println("pizza4--"+pizza4.getName());  
          session2.close();

Output is:

Hibernate: select pizza0_.id as id0_0_, pizza0_.name as name0_0_, pizza0_.price as price0_0_ from pizza pizza0_ where pizza0_.id=?
pizza2--Thin Crust
Hibernate: select pizza0_.id as id0_0_, pizza0_.name as name0_0_, pizza0_.price as price0_0_ from pizza pizza0_ where pizza0_.id=?
pizza4--Thin Crust

But it hit twice in database.I don't find anything wrong in my code.Please suggest me why it hit twice in database.

回答1:

I have solved my question.I need to add

@Cache(usage=CacheConcurrencyStrategy.READ_ONLY,region="pizza")

In domain class.

@Entity
@Cache(usage=CacheConcurrencyStrategy.READ_ONLY,region="pizza")
@Table(name = "pizza")
public class Pizza implements Serializable{

来源：https://stackoverflow.com/questions/20584585/hibernate-second-level-cache-example

标签

hibernate

Ehcache