问题描述
|
我有一个称为FooBean的抽象超类bean,而我所有的其他bean都扩展了该类。我已经将dao连接到applicationContext文件中,并且希望将其注入到此超类bean中,以便每次进入bean时都可以访问dao。问题是,每当我尝试访问子类中的dao时,都会收到NullPointerException。以下文件仅显示有关Spring设置的相关配置详细信息:
web.xml:
<listener>
<listener-class>
org.springframework.web.context.ContextLoaderListener
</listener-class>
</listener>
<listener>
<listener-class>
org.springframework.web.context.request.RequestContextListener
</listener-class>
</listener>
<context-param>
<description>Spring configuration files location.</description>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/config/applicationContext-*.xml</param-value>
</context-param>
faces-config.xml:
<application>
<variable-resolver>org.springframework.web.jsf.DelegatingVariableResolver</variable-resolver>
<el-resolver>org.springframework.web.jsf.el.SpringBeanFacesELResolver</el-resolver>
...
</application>
FooBean.java:
public abstract class FooBean implements Serializable {
protected transient FooService dao;
public void setFooService(FooService dao){
this.dao = dao;
}
}
applicationContext-service.xml:
<bean id=\"serviceTemplate\" class=\"org.springframework.transaction.interceptor.TransactionProxyfactorybean\" abstract=\"true\">
<property name=\"transactionManager\" ref=\"transactionManager\"/>
<property name=\"transactionAttributes\">
<props>
<prop key=\"*\"/>
<!--
<prop key=\"save*\">PROPAGATION_required</prop>
<prop key=\"delete*\">PROPAGATION_required</prop>
<prop key=\"remove*\">PROPAGATION_required</prop>
<prop key=\"find*\">PROPAGATION_required,readOnly</prop>
<prop key=\"get*\">PROPAGATION_required,readOnly</prop>
-->
</props>
</property>
</bean>
<!-- DeFinition of service targets -->
<bean id=\"fooServiceTarget\" class=\"com.foo.service.FooService\">
<property name=\"fooDAO\" ref=\"fooDAO\"/>
<property name=\"adminDAO\" ref=\"adminDAO\"/>
<property name=\"channelsDAO\" ref=\"channelsDAO\"/>
</bean>
<bean id=\"fooService\" parent=\"serviceTemplate\">
<property name=\"target\" ref=\"fooServiceTarget\"/>
</bean>
applicationContext-hibernate.xml:
<bean id=\"dataSource\" class=\"org.springframework.jndi.Jndiobjectfactorybean\">
<property name=\"jndiName\" value=\"jdbc/FooDataSource\"/>
</bean>
<!-- Hibernate SessionFactory -->
<bean id=\"sessionFactory\" class=\"org.springframework.orm.hibernate3.LocalSessionfactorybean\">
<property name=\"dataSource\" ref=\"dataSource\"/>
<property name=\"mappingResources\">
<list>
<!--value>com/Foo/model/General.hbm.xml</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.bytecode.use_reflection_optimizer\">true</prop>
<prop key=\"hibernate.search.default.directory_provider\">filesystem</prop>
<prop key=\"hibernate.search.default.indexBase\">/usr/lucene/indexes</prop>
<!--prop key=\"hibernate.cache.provider_class\">org.hibernate.cache.SwarmCacheProvider</prop-->
</props>
</property>
</bean>
<!-- Transaction manager for a single Hibernate SessionFactory (alternative to JTA) -->
<bean id=\"transactionManager\" class=\"org.springframework.orm.hibernate3.HibernateTransactionManager\">
<property name=\"sessionFactory\" ref=\"sessionFactory\"/>
</bean>
<!-- Spring Data Access Exception Translator Defintion -->
<bean id=\"jdbcExceptionTranslator\" class=\"org.springframework.jdbc.support.sqlErrorCodesqlExceptionTranslator\"/>
<bean id=\"hibernateTemplate\" class=\"org.springframework.orm.hibernate3.HibernateTemplate\">
<property name=\"sessionFactory\" ref=\"sessionFactory\"/>
<property name=\"jdbcExceptionTranslator\" ref=\"jdbcExceptionTranslator\"/>
</bean>
<!-- Add DAO\'s here and create separate application context for service -->
<bean id=\"FooDAO\" class=\"com.foo.service.dao.impl.FooDAOHibernate\">
<property name=\"hibernateTemplate\" ref=\"hibernateTemplate\"/>
</bean>
<bean id=\"adminDAO\" class=\"com.foo.service.dao.impl.AdminDAOHibernate\">
<property name=\"hibernateTemplate\" ref=\"hibernateTemplate\"/>
</bean>
<bean id=\"channelsDAO\" class=\"com.foo.service.dao.impl.ChannelsDAOHibernate\">
<property name=\"hibernateTemplate\" ref=\"hibernateTemplate\"/>
</bean>
我已经尝试过但没有成功的事情:
在FooBean类字段上使用@ManagedProperty(value = \“#{FooService} \”)进行了尝试。
尝试在faces-config.xml中定义一个bean来注入spring bean:
com.foo.beans.FooBean
没有
fooService
#{fooService}
将具有空指针的子类bean定义为spring bean,并通过spring bean xml文件注入属性。
具有讽刺意味的是,我能够将以下代码放入FooBean抽象类的构造函数中,并且注入了dao(但是我不想使用此代码,我想用spring来注入它):
WebApplicationContext ctx = WebApplicationContextUtils.getrequiredWebApplicationContext(getRequest().getServletContext());
dao = (FooService)ctx.getBean(\"fooService\");
解决方法
(我本来会以此为评论,但对此我没有足够的声誉)
如果使用@ManagedProperty,则还应该将其声明为@ManagedBean。
另外,我在任何applicationContext.xml文件中都没有看到FooBean,所以我看不到Spring如何“知道”它。
,相信这与使用jsf bean的方式有关。当请求新bean时,由于在部署时实例化了Spring Injects,因此不会注入dao。它在构造函数中起作用的原因是为请求创建了bean,然后您将获得应用程序上下文并获取dao Singleton。