爲什麼我的Hibernate會話總是空？

Question

我正在使用Hibernate連接到我的數據庫，當我想從數據庫加載數據我會話時得到空指針異常。我不知道爲什麼？一切看起來都對我好：< 我有這個類從數據庫中讀取：

package bbstats.domain; 

import bbstats.util.HibernateUtil; 
import org.hibernate.Session; 
import org.hibernate.SessionFactory; 
import org.springframework.beans.factory.annotation.Autowired; 

import java.util.List; 

public class EventManager extends HibernateUtil 
{ 

    @Autowired 
    SessionFactory sessionFactory; 

    protected Class<DbUserData> clazz; 

    public List<DbUserData> getAll() 
    { 
     return this.getCurrentSession().createCriteria(clazz).list(); 
    } 

    protected final Session getCurrentSession() 
    { 
     return this.sessionFactory.getCurrentSession(); 
    } 

    public static void main(String args[]) 
    { 
     EventManager eventManager = new EventManager(); 
     System.out.println(eventManager.getAll()); 
    } 
} 

package bbstats.util; 

import org.hibernate.SessionFactory; 
import org.springframework.beans.factory.annotation.Autowired; 
import org.springframework.orm.hibernate3.support.HibernateDaoSupport; 

public class HibernateUtil extends HibernateDaoSupport 
{ 
    private SessionFactory sessionFactory; 

    @Autowired 
    public void anyMethodName(SessionFactory sessionFactory) 
    { 
     setSessionFactory(sessionFactory); 
    } 
} 

package bbstats.domain; 

import javax.persistence.Column; 
import javax.persistence.Entity; 
import javax.persistence.Table; 
@Entity 
@Table(name = "Users") 
public class DbUserData 
{ 
    @Column(name = "id", unique = true, nullable = false) 
    private Long id; 
    @Column(name = "nick", nullable = false, length = 26) 
    private String title; 

    public DbUserData() {} 

    public Long getId() { 
     return id; 
    } 

    private void setId(Long id) { 
     this.id = id; 
    } 

    public String getTitle() { 
     return title; 
    } 

    public void setTitle(String title) { 
     this.title = title; 
    } 
} 

，當我嘗試運行它，我得到異常：

Exception in thread "main" java.lang.NullPointerException 
    at bbstats.domain.EventManager.getCurrentSession(EventManager.java:25) 

它在這裏：

protected final Session getCurrentSession() 
{ 
    return this.sessionFactory.getCurrentSession(); 
} 

爲什麼？我怎樣才能解決這個問題？

編輯： 我有這個標籤的文件 是對的嗎？我沒有其他文件的標籤

<beans xmlns="http://www.springframework.org/schema/beans" 
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
     xmlns:utils="http://www.springframework.org/schema/util" 
     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
    http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.0.xsd"> 

    <!-- Hibernate session factory --> 
    <bean id="sessionFactory" 
      class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean"> 
     <property name="dataSource" ref="dataSource"/> 
     <property name="hibernateProperties"> 
      <props> 
       <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop> 
       <prop key="hibernate.show_sql">true</prop> 
       <prop key="hibernate.hbm2ddl.auto">update</prop> 
      </props> 
     </property> 
     <property name="packagesToScan" ref="sessionFactoryDomainToScan"/> 

    </bean> 

    <utils:list id="sessionFactoryDomainToScan"> 
     <value>bbstats.domain</value> 
    </utils:list> 


    <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> 
     <property name="properties" ref="clientProperties"/> 
     <property name="ignoreUnresolvablePlaceholders" value="true"/> 
    </bean> 


    <bean id="clientProperties" 
      class="org.springframework.beans.factory.config.PropertiesFactoryBean"> 
     <property name="locations" value="/database.properties"/> 
    </bean> 

    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> 
     <property name="driverClassName" value="${jdbc.driverClassName}"/> 
     <property name="url" value="${jdbc.url}"/> 
     <property name="username" value="${jdbc.username}"/> 
     <property name="password" value="${jdbc.password}"/> 

    </bean> 
</beans> 

或者我應該爲我的EventManager類添加一些其他的bean？ 可能是一些豆子不需要？

依賴關係：

<dependency> 
     <groupId>org.springframework</groupId> 
     <artifactId>spring-core</artifactId> 
     <version>3.2.1.RELEASE</version> 
     <type>jar</type> 
     <scope>compile</scope> 
    </dependency> 
    <dependency> 
     <groupId>org.hibernate</groupId> 
     <artifactId>hibernate-core</artifactId> 
     <version>4.1.9.Final</version> 
     <type>jar</type> 
     <scope>compile</scope> 
    </dependency> 
    <dependency> 
     <groupId>org.hibernate</groupId> 
     <artifactId>hibernate-annotations</artifactId> 
     <version>3.5.6-Final</version> 
     <type>jar</type> 
     <scope>compile</scope> 
    </dependency> 
    <dependency> 
     <groupId>net.sourceforge.jtds</groupId> 
     <artifactId>jtds</artifactId> 
     <version>1.3.0</version> 
    </dependency> 
    <dependency> 
     <groupId>org.springframework</groupId> 
     <artifactId>spring-orm</artifactId> 
     <version>3.0.3.RELEASE</version> 
    </dependency> 

現在例外： Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'eventManager' defined in class path resource [hibernate.cfg.xml]: Cannot resolve reference to bean 'sessionFactory' while setting bean property 'sessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in class path resource [hibernate.cfg.xml]: Initialization of bean failed; nested exception is java.lang.NoClassDefFoundError: [Lorg/hibernate/engine/FilterDefinition; Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in class path resource [hibernate.cfg.xml]: Initialization of bean failed; nested exception is java.lang.NoClassDefFoundError: org/hibernate/cache/CacheProvider

Answer 1

爲了注入的SessionFactory（多虧了註釋@Autowired），豆EventManager必須由容器實例化（即春節）和不是（如你在你的主要方法中做的那樣：EventManager eventManager = new EventManager();）

Answer 2

您應該從spring上下文中檢索EventManager實例。

您可以在您的文件中將eventManager定義爲一個bean。你可以將其定義爲：

<bean id="eventManager" class="bbstats.domain.EventManager"> 
<property name="sessionFactory" ref="sessionFactory"/> 
</bean> 

比方說，你的Spring配置文件名是springConfig.xml和eventmanager進行定義爲豆，那麼你可以使用

ApplicationContext context = 
      new ClassPathXmlApplicationContext(new String[] {"springConfig.xml"}); 

     EventManager eventManager = (EventManager)context.getBean("eventManager"); 

Answer 3

刪除此方法：

@Autowired 
    public void anyMethodName(SessionFactory sessionFactory) 
    { 
     setSessionFactory(sessionFactory); 
    } 

並將@Autowired註釋添加到setSessionFactory方法。

UPDATE

海這個鏈接（在這裏你可以找到解決方案）：

1. first
2. second
3. therd