Hibernate5。xSpring5。x、 无法在DAOImpl类中自动连接SessionFactory

Question

我正在编写一个非常简单的crm网络应用程序，我在我的一个DAO类中自动装配hibernate essionFactory bean时遇到了问题。我已经在互联网上搜索了几天，我很困惑，因为我的配置似乎反映了那些据说在网络上工作的配置。在这个项目中，我不使用xml。

web servlet配置类

public class WebServletConfig implements WebApplicationInitializer
{

@Override
public void onStartup(ServletContext servletContext) throws ServletException
{
    AnnotationConfigWebApplicationContext webContext = new AnnotationConfigWebApplicationContext();
    webContext.register(SpringConfig.class);
    webContext.setServletContext(servletContext);
    ServletRegistration.Dynamic servlet = servletContext.addServlet("dispatcher", new DispatcherServlet(webContext));
    servlet.setLoadOnStartup(1);
    servlet.addMapping("/");
}
}

spring配置类

@Configuration
@EnableWebMvc
@ComponentScan("com.crmproject")
public class SpringConfig implements WebMvcConfigurer 
{

@Bean
public ViewResolver viewResolver()
{
    InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
    viewResolver.setViewClass(JstlView.class);
    viewResolver.setPrefix("/WEB-INF/pages/");
    viewResolver.setSuffix(".jsp");

    return viewResolver;
}

@Bean
public MessageSource messageSource()
{
    ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
    messageSource.setBasename("resources/messages");

    return messageSource;
}

public void configureDefaultSevletHandling(DefaultServletHandlerConfigurer configurer)
{
    configurer.enable();
}

}

Hibernate配置文件

@Configuration
public class HibernateConfig
{

@Bean
public LocalSessionFactoryBean sessionFactory()
{
    LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean();
    sessionFactory.setDataSource(dataSource());
    sessionFactory.setPackagesToScan("com.crmproject.entity");
    sessionFactory.setHibernateProperties(hibernateProperties());

    return sessionFactory;
}

@Bean
public DataSource dataSource()
{
    BasicDataSource dataSource = new BasicDataSource();
    dataSource.setDriverClassName("com.mysql.cj.jdbc.Driver");
    dataSource.setUrl("jdbc:mysql://localhost:3306/web_customer_tracker?useSSL=false&serverTimezone=UTC");
    dataSource.setUsername("hbstudent");
    dataSource.setPassword("hbstudent");

    return dataSource;
}

private final Properties hibernateProperties()
{
    Properties hibernateProperties = new Properties();
    hibernateProperties.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQLDialect");
    hibernateProperties.setProperty("hibernate.show_sql", "true");

    return hibernateProperties;
}

}

我试图在这个DAO类中自动连接sessionFactory，但当我调用testMethod查看sessionFactory是否已被注入时，它会抛出NullPointerException。

@Repository
public class CustomerDAOImpl implements CustomerDAO
{

@Autowired
private SessionFactory sessionFactory;


public void setSessionFactory(SessionFactory sessionFactory)
{
    this.sessionFactory = sessionFactory;
}

public void testMethod()
{
    System.out.println(sessionFactory.toString());
}

public CustomerDAOImpl()
{
    System.out.println("in CustomerDAOImpl constructor");
}

public List<Customer> getCustomers()
{
    return null;
}

public Integer saveCustomer(Customer customer)
{
    return null;
}

public Customer getCustomer(Integer id)
{
    return null;
}

public boolean updateCustomer(Integer id, Customer customer)
{
    return false;
}

public boolean deleteCustomer(Integer id)
{
    return false;
}
}

例外情况：

SEVERE： Sorg.springframework.web.method.support.（）为servlet[调度程序]在上下文中的路径[/crm2-project]抛出异常[请求处理失败；嵌套异常是ethod.doNullPointerException]与根本原因ethod.java:209NullPointerException在org.springframework.web.method.support.CustomerDAOIethod.invoke方法（CustomerDAOIethod.java:136）在org.springframework.web.servlet.mvc.method.annotation.CustomerCethod.invoke客户（CustomerCethod.java:102）在org.springframework.web.servlet.mvc.method.annotation.NativeMachodAccessorIdapter.invoke0（Native method）在sun.reflect.NativeMachodAccessorImpl.invoke（NativeMEodAccessorImpl.java:62）在sun.reflect.在java.lang.reflect.Method.invoke（Method.java:498）在ervlet.serviceInvocableHandlerMjava.lang.Invoke（InvocableHandlerMjava.lang.）在com.crmproject.dao.InvocableHandlerMmpl.testForRequest（InvocableHandlerMmpl.java:26）在com.crmproject.controller.ServletInvocableHandlerMontroller.listAndHandle（ServletInvocableHandlerMontroller.java:31）在sun.reflect.Request estMappingHandlerAmpl.invokeHandlermethodFrameworkServlet. service（FrameworkServlet. java： 851）位于javax. servlet. http。HttpServlet. service（HttpServlet. java： 741）位于org. apache. catalina. core。org. apache. catalina. core处的Application ationFilterChain. interalDoFilter（Application ationFilterChain. java： 231）。org. apache. tomcat. websocket. server处的Application ationFilterChain. doFilter（Application ationFilterChain. java： 166）。org. apache. catalina. core处的WsFilter. doFilter（WsFilter. java： 53）。org. apache. catalina. core处的Application ationFilterChain. java： 193。org. apache. catalina. core处的Application ationFilterChain. doFilter（Application ationFilterChain. java： 166）。标准WtaskThread$WrappingRunnable. run（TaskThread. java： 61）在java. lang. Thread. run（Thread. java： 748）

为什么Spring没有注入essionFactory bean？

编辑：为每个请求添加控制器代码

@Controller
@RequestMapping("/customer")
public class CustomerController
{

@RequestMapping("/customerAddForm")
public String showAddCustomerForm(Model model)
{
    model.addAttribute("customer", new Customer());
    System.out.println("Inside showAddCustomerForm method");
    return "customer-add-form";
}

@RequestMapping("/list")
public String listCustomers(Model model)
{
    List<Customer> customers = new ArrayList<>();
    new CustomerDAOImpl().testMethod();
    model.addAllAttributes(customers);

    return "list-customers";
}

@RequestMapping("/proccessAddForm")
public void proccessAddForm(@ModelAttribute("customer")Customer customer)
{
    System.out.println("Inside proccessAddForm method, customer: " + customer.toString());
}

}

Answer 1

问题出在我的控制器类中。我尝试使用“new CustomerDAOImpl（）.testMethod（）；”创建CustomerDAOImpl对象。斯普林显然不喜欢它。我将其更改为“@Autowired CustomerDAOImpl CustomerDAOImpl；”现在它开始工作了，NullPointerException消失了。这是一个多么愚蠢的错误，但同时也是一次伟大的学习经历。谢谢你的帮助！