[英]Annotation not working in spring
我是春季的初學者,春季有dao類。但是注釋@autowired或@service無法正常工作,我已經通過在應用程序上下文中創建bean解決了該問題,這是為什么注釋在春季不起作用的原因。還提供了“ context:component-scan base-package =“,但注釋不起作用
StudentDao
public interface StudentDao {
public int addStudent(StudentEntity s);
}
-----------------------------------
@Service("studentDaoImpl")
public class StudentDaoImpl implements StudentDao{
@PersistenceContext
private EntityManager em;
@Override
@Transactional
public int addStudent(StudentEntity student) {
// TODO Auto-generated method stub
em.persist(student);
return student.getId();
}
}
------------------------------------------------
FascadeDaoImpl
public class FascadeControllerImpl implements FascadeController {
// @Autowired
private StudentDao studentDao;
private UserContext uc;
public void studentDao() {
studentDao=(StudentDao) uc.getContext().getBean("studentDao");
}
}
public int addStudent(StudentEntity student) {
studentDao();
return studentDao.addStudent(student);
}
ApplicationContext
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-4.0.xsd">
<context:component-scan base-package="sms.spring.dao" />
<context:component-scan base-package="sms.spring.fascade" />
<context:component-scan base-package="sms.spring.entity" />
<context:annotation-config />
<bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor"/>
<bean class="sms.spring.entity.StudentEntity" id="studentbean"/>
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName">
<value>com.microsoft.sqlserver.jdbc.SQLServerDriver</value>
</property>
<property name="url">
<value>jdbc:sqlserver://localhost;databaseName=dbstsms</value>
</property>
<property name="username">
<value>sa</value>
</property>
<property name="password">
<value>sa123</value>
</property>
</bean>
<bean id="entityManagerFactory"
class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="persistenceXmlLocation" value="classpath:META-INF/persistence.xml" />
<property name="persistenceUnitName" value="PERSUnit" />
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" />
</property>
<property name="jpaProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.SQLServer2008Dialect</prop>
<prop key="hibernate.show_sql">true</prop>
<prop key="hibernate.hbm2ddl.auto">update</prop>
</props>
</property>
</bean>
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
<bean id="fascadeController" class="sms.spring.fascade.FascadeControllerImpl"></bean>
<bean id="studentDao" class="sms.spring.dao.StudentDaoImpl"></bean>
<bean id="loginDao" class="sms.spring.dao.LoginDaoImpl"></bean>
<bean id="facultyDao" class="sms.spring.dao.FacultyDaoImpl"></bean>
<bean id="markDao" class="sms.spring.dao.MarkDaoImpl"></bean>
<bean id="notificationDao" class="sms.spring.dao.NotificationDaoImpl"></bean>
<tx:annotation-driven />
問題尚不清楚,但是看起來您的控制器也應該使用@Controller
進行注釋。 屬於Spring項目且具有自動關聯的所有類都需要由Spring創建。 簡而言之,您絕對不應new
一個Spring類並使用ApplicationContext#getBean()
或在其他類注入它時創建它們。
此外,請記住構造函數,因為在創建bean時,自動裝配的依賴關系為null(未初始化),因此您需要創建一個帶有@PostConstruct
注釋的init()
方法。
兩個主要原因是:
您必須告訴spring,在哪里掃描您的組件(確保軟件包正確)。
您沒有實際的bean實現(請確保StudentDao也具有@Service)
請發布您得到的錯誤,也可以從發布的代碼中看到,即使您已經使用@service注釋對StudentDaoImpl類進行了注釋,您仍在xml配置中定義了相同的代碼,請使用基於注釋的config或基於xml的配置。
請檢查您的文件是否包含
<context:annotation-config/>
(如果啟用了組件掃描,則不需要)
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