SSH项目整合——XML文档流


编程中总会遇到头疼的问题，各种莫名奇妙的错误，这个错误调试了一下午，终于在老师的帮助下解决了。

错误信息：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'loginBean' defined in ServletContext resource [/WEB-INF/applicationContext.xml]: Cannot resolve reference to bean 'userDAo' while setting bean property 'userDAO';
nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userDAo' defined in ServletContext resource [/WEB-INF/applicationContext.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 ServletContext resource [/WEB-INF/applicationContext.xml]: Cannot resolve reference to bean 'dataSource'
while setting bean property 'dataSource'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.aop.aspectj.AspectJPointcutAdvisor': Cannot resolve reference to bean 'txAdvice' while
setting bean property 'advice';

这个错误竟然是因为ApplicationContext.xml文件中bean标签的顺序问题，将自己的bean定义放在了sessionFactory 的 bean的上面，而XML文档流是由上向下寻找节点的，hibernate是先建立sessionFactory，再由sessionFactory实例化其他bean，所以自己的bean定义要放在sessionFactory定义的下面，才能正确实例化。

例：

Appli

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"

xmlns:tx="http://www.springframework.org/schema/tx"

xsi:schemaLocation="

http://www.springframework.org/schema/beans ;

classpath:org/springframework/beans/factory/xml/spring-beans.xsd

http://www.springframework.org/schema/aop ;

classpath:org/springframework/aop/config/spring-aop.xsd

http://www.springframework.org/schema/tx

classpath:org/springframework/transaction/config/spring-tx.xsd">



<!-- 定义数据源 -->

<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">

<!-- 指定连接数据库的JDBC驱动 -->

<property name="driverClass" value="com.mysql.jdbc.Driver">

</property>

<!-- 连接数据库所用的URL -->

<property name="jdbcUrl" value="jdbc:mysql://localhost:3306/user?useUnicode=true&characterEncoding=utf-8">

</property>

<!-- 连接数据库的用户名 -->

<property name="user" value="root">

</property>

<!-- 连接数据库的密码 -->

<property name="password" value="root">

</property>

<!-- 设置数据库连接池的最大连接数 -->

<property name="maxPoolSize" value="20">

</property>

<!-- 设置数据库连接池的最小连接数 -->

<property name="minPoolSize" value="2">

</property>

<!-- 设置数据库连接池的初始化连接数 -->

<property name="initialPoolSize" value="2">

</property>

<!-- 设置数据库连接池的连接的最大空闲时间,单位为秒 -->

<property name="maxIdleTime" value="20">

</property>

</bean>



<!-- 定义sessionFactory -->

<bean id="sessionFactory"

class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">

<property name="dataSource">

<ref bean="dataSource" />

</property>

<!-- 配置hibernate实体映射关系 -->

<property name="annotatedClasses">

<list>

<value>com.freedom.bean.User</value>

</list>

</property>

<property name="hibernateProperties">

<props>

<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>

<prop key="hibernate.show_sql">true</prop>

<prop key="hibernate.format_sql">true</prop>

<prop key="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</prop>

<!--<prop key="hibernate.cache.use_second_level_cache">false</prop>

<prop key="hibernate.cache.use_structured_entries">false</prop>

<prop key="hibernate.jdbc.use_scrollable_resultset">true</prop>-->

<prop key="hibernate.cache.use_query_cache">false</prop>



</props>

</property>

<!--hibernate search配置-->

<!--

<property name="eventListeners">

<map>

<entry key="post-update">

<bean class="org.hibernate.search.event.FullTextIndexEventListener"/>

</entry>

<entry key="post-insert">

<bean class="org.hibernate.search.event.FullTextIndexEventListener"/>

</entry>

<entry key="post-delete">

<bean class="org.hibernate.search.event.FullTextIndexEventListener"/>

</entry>

</map>

</property>

-->

</bean>



<!-- 定义数据源 end -->



<!-- 定义事务 -->



<bean id="transactionManager"

class="org.springframework.orm.hibernate3.HibernateTransactionManager">

<property name="sessionFactory">

<ref bean="sessionFactory" />

</property>

</bean>

<!-- 定义事务 end -->



<!-- bean的定义要放在SessionFactory的下面 -->

<bean id="loginBean" class="com.freedom.action.LoginAction">

<property name="userDAO" ref="userDAo"></property>

</bean>



<bean id="userDAo" class="com.freedom.dao.UserDao">

<property name="sessionFactory" ref="sessionFactory" />

</bean>



<!-- 配置spring事务特性，配置add,delete,update开始的方法，事务传播特性为required -->

<tx:advice id="txAdvice" transaction-manager="transactionManager">

<tx:attributes>

<tx:method name="add*" propagation="REQUIRED"/>

<tx:method name="delete*" propagation="REQUIRED"/>

<tx:method name="update*" propagation="REQUIRED"/>

<!-- <tx:method name="*" propagation="REQUIRED" /> -->

</tx:attributes>

</tx:advice>



<!-- 配置哪些类的方法行进事务管理，当前com.model包中的子包,类中所有方法需要，还需要参考tx:advice的设置 -->

<aop:config>

<aop:pointcut id="interceptorPointCuts"

expression="execution(* com.freedom.dao.*.*(..))" />

<aop:advisor advice-ref="txAdvice"

pointcut-ref="interceptorPointCuts" />

</aop:config>

</beans>