java - Spring @Autowired 注入(inject)不起作用 : DAO is always null

Question

我正在开发一个 EAR，其操作由 Struts 处理，bean 由 Spring 处理。该 EAR 包括 3 个 .jar 文件、公共(public)文件 (DS/US/DAO) 的引用以及一个 .war、myProjectWeb。

代码:

Struts 操作(在 myProjectWeb 中):

public class MyAction extends DispatchAction {

    private IMyPreferencesDS myPreferences;

    protected ActionForward executeAction(ActionMapping mapping, ActionForm form, 
        HttpServletRequest request, HttpServletResponse response) throws Exception {
        // newValue is got from my form
        myPreferences.updatePreferences(newValue);
    }
}

不同的 DS(在 myProject-commons 中):

IMyPreferencesDS:

public interface IMyPreferencesDS extends IAbstractDSGeneric<MyDTO> {

    void updatePreferences(String newValue) throws JrafDomainException;

}

MyPreferencesDS:

public class MyPreferencesDS implements IMyPreferencesDS {

    @PersistenceContext(unitName="myPersistenceUnit")
    private EntityManager entityManager;

    @Autowired
    @Qualifier("myPreferencesDAOBean")
    private IMyPreferencesDAO mainDao;

    @Transactional(rollbackFor = JrafDomainRollbackException.class, 
        noRollbackFor = JrafDomainNoRollbackException.class)
    public void updatePreferences(String newValue) throws JrafDomainException {

        mainDao.setNewPreferencesValue(newValue);

    }
}

IMyPreferencesDAO:

public interface IMyPreferencesDAO extends IAbstractDAOGeneric<MyEntity> {

    void setNewPreferencesValue(String newValue) throws JrafDaoException;

}

MyPreferencesDAO:

public class MyPreferencesDAO extends AbstractDAOGenericImpl<MyEntity> implements IMyPreferencesDAO {

    public void setNewPreferencesValue(String newValue) throws JrafDaoException {
        StringBuilder strQuery = new StringBuilder();
        strQuery.append("update MYBASE.MYTABLE ");
        strQuery.append("set");
        strQuery.append(" PREFS=:newValue, ");

        final Query myQuery = getEntityManager().createNativeQuery(strQuery.toString(), MyEntity.class);
        myQuery.setParameter("newValue", newValue);

        try {
            return myQuery.executeUpdate();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

配置:

在myProjectWeb中:

struts-config:

<form-bean name="MyForm" type="com.my.MyForm"/>
<action input="/media/modificationPopup.jsp" name="MyForm" path="/media/prefModif" 
    scope="request" type="org.springframework.web.struts.DelegatingActionProxy" 
    validate="true"/>

操作依赖项:

<bean name="/media/prefModif" class="com.my.action.MyAction" scope="singleton">
    <property name="myPreferences" ref="myPreferencesDS" />
</bean> 

application-context-spring:

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:jee="http://www.springframework.org/schema/jee"
    xsi:schemaLocation="http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans-2.5.xsd 
    http://www.springframework.org/schema/tx 
    http://www.springframework.org/schema/tx/spring-tx-2.5.xsd 
    http://www.springframework.org/schema/context 
    http://www.springframework.org/schema/context/spring-context-2.5.xsd 
    http://www.springframework.org/schema/jee 
    http://www.springframework.org/schema/jee/spring-jee-2.5.xsd">

    <!-- Enterprise layer's dependencies -->
    <import resource="classpath:ioc/0-ref-commons-enterpriselayer-dependencies.xml" />

    <bean id="springLocator" class="com.afklm.jraf.bootstrap.locator.SpringLocator"></bean>

    <bean id="persistenceUnitManager" class="org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager">
        <property name="persistenceXmlLocations">
            <list>
                <value>classpath*:META-INF/persistence-web.xml</value>
            </list>
        </property>
    </bean>

    <bean id="myEmf" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="persistenceUnitManager" ref="persistenceUnitManager" />
        <property name="persistenceUnitName" value="myPersistenceUnit" />
    </bean>

    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="myEmf" />
    </bean>

    <tx:annotation-driven transaction-manager="transactionManager" />

    <context:component-scan base-package="com.my.action" /> 
</beans>

0-ref-commons-enterpriselayer-dependency.xml 包含在 commons jar 中:

<beans xmlns="http://www.springframework.org/schema/beans"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd">
    <import resource="1-ref-commons-ds-dependencies.xml"/>
    <import resource="2-ref-commons-us-dependencies.xml"/>
    <import resource="3-ref-commons-daos-dependencies.xml"/>
</beans>

它包含所请求的 DS 和 DAO，如下所示:

在1-ref-commons-ds-dependency.xml

<!-- MyPreferencesDS Component -->
<bean id="myPreferencesDS" class="com.commons.ds.MyPreferencesDS" scope="prototype">
</bean>

在3-ref-commons-daos-dependency.xml

<!-- MyPreferencesDAO Component -->
<bean id="myPreferencesDAOBean" class="com.commons.daos.MyPreferencesDAO" scope="prototype">
</bean>

所有库都在我的 EAR 中:

并导入到我的 Web .war 中:

我的EAR模块组装:

好吧，就是这样...但是当我尝试在 MyPreferencesDS 中调用此行时:

mainDao.setNewPreferencesValue(newValue);

ma​​inDao 始终为 null，并且我收到 NullPointerException... 似乎 @Autowired 注入(inject)在那里不起作用。

感谢您的帮助...

Answer 1

Ypu 混合了 @Autowiring 和通过 xml 直接分配。

您的 myAction 没有自动连接首选项。您通过 ref 设置它

<bean name="/media/prefModif" class="com.my.action.MyAction" scope="singleton">
    <property name="myPreferences" ref="myPreferencesDS" />
</bean> 

所以用ref同样的方式定义dao ref。

<bean id="myPreferencesDS" class="com.commons.ds.MyPreferencesDS" scope="prototype">
    <property name="mainDao" ref="myPreferencesDAOBean" />
</bean>

或者使用@Autowire将首选项注入(inject)到Action中