[英]Spring @Autowired injection doesn't work : DAO is always null
我正在研究EAR,並在Spring之前由Struts和bean處理動作。 該EAR包含3個.jar
文件,commons文件(DS / US / DAO)的引用以及.war
, myProjectWeb 。
代碼:
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"/>
actions-dependencies
:
<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-dependencies.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>
它包含請求的DS和DAO,如下所示:
在1-ref-commons-ds-dependencies.xml
<!-- MyPreferencesDS Component -->
<bean id="myPreferencesDS" class="com.commons.ds.MyPreferencesDS" scope="prototype">
</bean>
在3-ref-commons-daos-dependencies.xml
<!-- MyPreferencesDAO Component -->
<bean id="myPreferencesDAOBean" class="com.commons.daos.MyPreferencesDAO" scope="prototype">
</bean>
所有的庫都在我的EAR中:
並導入到我的Web .war中:
我的EAR的模塊組裝如下:
好的,這是...但是,當我嘗試在MyPreferencesDS中調用此行時 :
mainDao.setNewPreferencesValue(newValue);
mainDao始終為null,並且我收到NullPointerException
...似乎@Autowired
注入在那里不起作用。
謝謝你的幫助...
Ypu混合了@Autowiring和通過xml直接分配。
您的myAction沒有自動裝配的首選項。 您通過ref進行設置
<bean name="/media/prefModif" class="com.my.action.MyAction" scope="singleton">
<property name="myPreferences" ref="myPreferencesDS" />
</bean>
因此,用ref以相同的方式定義dao ref。
<bean id="myPreferencesDS" class="com.commons.ds.MyPreferencesDS" scope="prototype">
<property name="mainDao" ref="myPreferencesDAOBean" />
</bean>
或者使用@Autowire將偏好設置注入到Action中
您沒有在掃描“ com.commons
”軟件包。 由於“ com.commons.ds.MyPreferencesDS
”位於該軟件包中,因此spring甚至不需要為其自動com.commons.ds.MyPreferencesDS
該軟件包的bean。 您可能想在application-context-spring
嘗試以下行:
<context:component-scan base-package="com.my.action, com.commons" />
如果您不希望“ com.commons
”下的所有軟件包,並且更具體地說明要掃描的軟件包並列出所有軟件包:
<context:component-scan base-package="com.my.action, com.commons.ds, com.commons.daos" />
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