在 tomcat 开始时，自动装配：向 class 的侦听器实例发送上下文初始化事件的异常

Question

我尝试使用 find all 从 db 获取所有更新，但给出了这个错误。我使用调试，我在 ServletContextListener 中看到 dbUpdatesService 为空。我认为有些东西是自动装配的，只是我想不通。在控制器 classes 中，它在 ServletContextListener 中工作正常，但不行。我尝试在 ServletContextListener class 之前放置 @Controller 或 @Component 或 @Serviece 注释，但没有帮助我。有什么想法吗？

ServletContextListener

public class HRMSServletContextListener implements ServletContextListener {
@Autowired
    private IDbUpdatesService dbUpdatesService = new DbUpdatesService();

@Override
    public void contextInitialized(ServletContextEvent arg0) {
        LOGGER.info("Servlet context created.");

        chechFolderExistence();

        checkNewUpdate();
    }

private void checkNewUpdate(){
        LOGGER.info("Cheching for new Updates.");
        List<DbUpdates> updates = new ArrayList<DbUpdates>();

        updates = dbUpdatesService.findAll();
    }

spring-config.xml

        <context:annotation-config/>
        <context:component-scan base-package="com.atni.hrms" />
        <context:property-placeholder location="classpath:database.properties" />

        <bean id="txManager" 
            class="org.springframework.orm.hibernate4.HibernateTransactionManager" 
            name="txManager">  
            <property name="sessionFactory" ref="sessionFactory" />
        </bean>

抽象服务

@Override
    @Transactional("txManager")
    public List<T> findAll() {
        return getDao().findAll();
    }

DbUpdateService

@Service("iDbUpdatesService")
@Transactional(propagation = Propagation.SUPPORTS, readOnly = true)  
public class DbUpdatesService extends  AbstractService<DbUpdates, Long> implements IDbUpdatesService{

    @Autowired
    private IDbUpdatesDao DbUpdatesDao;

    public DbUpdatesService() {
        super();
    }

    public void setDbUpdatesDao(IDbUpdatesDao DbUpdatesDao) {
        this.DbUpdatesDao = DbUpdatesDao;
    }

    @Override
    protected IOperations<DbUpdates, Long> getDao() {
        return DbUpdatesDao;
    }

}

错误

SEVERE: Exception sending context initialized event to listener instance of class com.atni.hrms.persistence.model.listeners.HRMSServletContextListener
java.lang.NullPointerException
    at com.awinta.hrms.persistence.service.common.AbstractService.findAll(AbstractService.java:24)
    at com.awinta.hrms.persistence.model.listeners.HRMSServletContextListener.checkNewUpdate(HRMSServletContextListener.java:69)
    at com.awinta.hrms.persistence.model.listeners.HRMSServletContextListener.contextInitialized(HRMSServletContextListener.java:47)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4791)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5285)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)

Answer 1

不确定是否应该在需要自动装配时创建新对象

@Autowired
private IDbUpdatesService dbUpdatesService = new DbUpdatesService();

尝试

@Autowired
private IDbUpdatesService dbUpdatesService;

Answer 2

我的问题找到了一个很好的答案，首先是@Alan Barrows 说我不需要 new DbUpdatesService(); 然后我用了这个

@Override
public void contextInitialized(ServletContextEvent sce) {
    WebApplicationContextUtils
        .getRequiredWebApplicationContext(sce.getServletContext())
        .getAutowireCapableBeanFactory()
        .autowireBean(this);

    //Do something with props
    ...
}

在 tomcat 开始时，自动装配：向 class 的侦听器实例发送上下文初始化事件的异常

On tomcat starts,autowired: Exception sending context initialized event to listener instance of class

java

spring

tomcat

autowired

ServletContextListener

spring-config.xml

抽象服务

DbUpdateService

错误