Spring mvc Spring3,Hibernate4使用通用DAO自动连接sessionFactory
使用Spring MVC 3和Hibernate 4,我得到:Spring mvc Spring3,Hibernate4使用通用DAO自动连接sessionFactory,spring-mvc,spring-3,hibernate-4.x,hibernate-generic-dao,Spring Mvc,Spring 3,Hibernate 4.x,Hibernate Generic Dao,使用Spring MVC 3和Hibernate 4,我得到: java.lang.NullPointerException com.daniel.rr.dao.common.DAOImpl.getSession(DAOImpl.java:22) com.daniel.rr.dao.common.DAOImpl.save(DAOImpl.java:27) com.daniel.rr.controller.HelloController.printWelcome(HelloController.
java.lang.NullPointerException
com.daniel.rr.dao.common.DAOImpl.getSession(DAOImpl.java:22)
com.daniel.rr.dao.common.DAOImpl.save(DAOImpl.java:27)
com.daniel.rr.controller.HelloController.printWelcome(HelloController.java:30)
这是相关的spring配置:
<context:annotation-config />
<tx:annotation-driven transaction-manager="transactionManager" />
<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="packagesToScan">
<list>
<value>com.daniel.rr.model</value>
<value>com.daniel.rr.dao</value>
<value>com.daniel.rr.dao.common</value>
<value>com.daniel.rr.controller</value>
</list>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
<prop key="hibernate.show_sql">true</prop>
<prop key="hibernate.hbm2ddl.auto">update</prop>
</props>
</property>
<property name="dataSource" ref="dataSource" />
</bean>
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="url" value="jdbc:mysql://localhost:3306/rr" />
<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="username" value="root" />
<property name="password" value="" />
</bean>
<bean name="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory" />
</bean>
我已经通过StackOverflow和Google搜索过了,但是我找不到任何有用的东西。
我尝试在DAOImpl.save(T)上使用事务,但它仍然存在相同的问题
public T save(T t) {
Transaction tr = getSession().getTransaction();
tr.begin();
getSession().persist(t);
tr.commit();
return t;
}
注释不是继承的 将事务性注释添加到具体的dao,而不是抽象类
谢谢!找到了解决办法。
public class AccountDAO extends DAOImpl<Account> implements DAO<Account> {
}
public class HelloController {
@RequestMapping(method = RequestMethod.GET)
public String printWelcome(ModelMap model) {
//System.out.println("is null? " + sessionFactory);
AccountDAO dao = new AccountDAO();
Account account = new Account();
account.setUsername("hello");
account.setPassword("test");
dao.save(account);
model.addAttribute("message", "Hello world!");
return "hello";
}
}
public T save(T t) {
Transaction tr = getSession().getTransaction();
tr.begin();
getSession().persist(t);
tr.commit();
return t;
}