java - Hibernate 查询缓存，行为不符合预期

Question

我刚刚浏览了 this article和 this我发现这将提高我的应用程序的性能，因为它只有 99% 的读取操作。我首先在测试应用程序中实现它只是为了测试它(引用 this )，虽然我得到了结果但是根据我提到的第二个链接，如果查询对于 same 参数值相同，数据库命中将发生，但基于关系的主键。

类如下:

实体类

@Entity(name="User_Details")
public class UserDetails {
    @Id
    private String userName;
    private String password;
    private String  name;
    private Long msisdn;
   //getter and setter are in place//
}

DAO 类

public class UserDetailsDAOImpl {

SessionFactory sessionFactory;

public UserDetailsDAOImpl() {
    sessionFactory = new Configuration().configure().buildSessionFactory();
}

public UserDetails getUser(String param1) {
    Session session = sessionFactory.openSession();
    System.out.println("session : " + session);     
    session.beginTransaction();        
    Criteria query =  session.createCriteria(UserDetails.class).add(Restrictions.eq("name",param1));
    UserDetails dummy_user=(UserDetails) query.setCacheable(true).uniqueResult();
    session.close();
    return dummy_user;
}

主类

    UserDetailsDAOImpl obj=new UserDetailsDAOImpl();        
    UserDetails response = obj.getUser("Borat16");  
    System.out.println("Test:"+response);   
    UserDetails response1 = obj.getUser("Borat16"); 
    System.out.println("Test1:"+response1); 

Hibernate.cfg.xml

    <property name="hibernate.cache.use_second_level_cache">true</property>
    <!--<property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>-->
     <property name = "hibernate.cache.use_query_cache">org.hibernate.cache.EhCacheProvider</property>
    <property name="show_sql">true</property>
    <property name="hbm2ddl.auto">update</property>

//第一个查询结果:根据文章，第一次会命中数据库(如预期的那样)

Hibernate: select this_.userName as userName1_0_0_, this_.msisdn as msisdn2_0_0_, this_.name as name3_0_0_, this_.password as password4_0_0_ from User_Details this_ where this_.name=?
Test:UserDetails [userName=ak416, password=magnum16, name=Borat16, msisdn=116]

//第二个查询结果 :既然查询是相同的并且参数相同，为什么生成的 sql 语句看起来不像“select * from user_details where userName='ak47'。我的意思是它应该使用 where parameter as key 命中数据库。我缺少什么？!

Hibernate: select this_.userName as userName1_0_0_, this_.msisdn as msisdn2_0_0_, this_.name as name3_0_0_, this_.password as password4_0_0_ from User_Details this_ where this_.name=?
Test1:UserDetails [userName=ak416, password=magnum16, name=Borat16, msisdn=116]

Answer 1

你正在使用

<property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>

所以你的缓存没有启用(NoCacheProvider)