休眠：麻煩啓用二級緩存

Question

我正在使用Hibernate 3.3.4.GA.在我們的hibernate.cfg.xml文件，我們指定...

<property name="hibernate.cache.provider_class">net.sf.ehcache.hibernate.SingletonEhCacheProvider</property> 
    <property name="hibernate.cache.use_query_cache">true</property> 
    <property name="hibernate.cache.use_second_level_cache">true</property> 
    <property name="hibernate.cache.provider_configuration">classpath:ehcache.xml</property> 
    <property name="hibernate.show_sql">true</property> 
    <property name="hibernate.format_sql">true</property> 
    <property name="hibernate.use_sql_comments">true</property> 
    <property name="hibernate.generate_statistics">true</property> 
    <property name="hibernate.cache.use_structured_entries">true</property> 

但在零命中計數和零命中次數，這完全是混淆執行測試對DB（從JUnit的）結果...

@Test 
public void testCache() { 
    final String cacheRegion = WebLead.class.getCanonicalName(); 
    final SecondLevelCacheStatistics settingsStatistics = sessionFactory.getStatistics().getSecondLevelCacheStatistics(cacheRegion); 

    // Make first query. 
    webLeadsDAO.getLeads(lead); 
    System.out.println("miss count:" + settingsStatistics.getMissCount()); 
    System.out.println("hit count:" + settingsStatistics.getHitCount()); 

    // Make second query, expect this to hit cache. 
    webLeadsDAO.getLeads(lead); 
    System.out.println("after second query, hit count: " + settingsStatistics.getHitCount()); 
} 

下面是我們用於檢索結果的方法。任何錯過計數和命中數的想法都是零？

@Entity 
@Cache(usage=CacheConcurrencyStrategy.READ_ONLY) 
@Table(name="LEAD") 
public WebLeads getLeads(WebLead webLead) { 
    final Session session = sessionFactory.openSession(); 
    final Criteria crit = session.createCriteria(WebLead.class); 
    crit.setCacheable(Boolean.TRUE); 

    // Find webLeads matching input 
    crit.add(Example.create(webLead)); 
    // Make special exception for primary key since that isn't covered by Example.create 
    if (webLead.getLEAD_ID() != null) { 
     crit.add(Restrictions.eq("LEAD_ID", webLead.getLEAD_ID())); 
    } // if 

    @SuppressWarnings("unchecked") 
    final List<WebLead> results = crit.list(); 
    final WebLeads webLeads = new WebLeads(); 
    webLeads.addAll(results); 

    session.close(); 
    return webLeads; 
} 

顯然緩存未啓用，但我不明白爲什麼。 - 戴夫

Answer 1

請點擊這裏查看我的回答對工作的二級緩存配置：

Second Level Cache Configuration

我希望它能幫助。

UPDATE：

試試這個：

Statistics stats = sessionFactory.getStatistics(); 
stats.setStatisticsEnabled(true); 
SecondLevelCacheStatistics cacheStats = stats.getSecondLevelCacheStatistics(cacheRegion); 

Answer 2

您在使用Hibernate 3.3.4，但在配置cache.provider_class這是pre 3.3 Hibernate。

檢查此鏈接瞭解詳情：http://ehcache.org/documentation/user-guide/hibernate