java - Spring 无法创建 sessonFactory bean

Question

我在我的应用程序中不使用 .xml 文件，而是使用配置类，在尝试运行我的应用程序时，我收到以下错误消息:无法实例化 [org.springframework.orm.hibernate5.LocalSessionFactoryBean]:工厂方法“getSessionFactory”抛出异常；嵌套异常是java.lang.NullPointerException。

@Component
public interface FooService {
  public void add(Foo body);
}

   @Service
    public class FooServiceImpl implements FooService {

      @Autowired
      FooDao dao;

      @Transactional
      @Override
      public void add(Foo body) {
        dao.add(body);
      }
    }


public interface FooDao {
  void  add(Foo body);
}

@Repository
public class FooDaoImpl implements FooDao{

  @Autowired
  private SessionFactory sessionFactory;

  @Override
  public void add(Foo body) {
    sessionFactory.getCurrentSession().save(body);
  }
}

我以为我在类中混合了注释，但是，在 stackoverflow 上查看了一些答案，比较了 @Autowired 字段，但没有注意到任何差异。也许我无法注意到这里的一些小错误，猜猜哪里实现错了？

我的配置类是一个非常标准的配置类:

@Configuration
@PropertySource("classpath:db.properties")
@EnableTransactionManagement
@ComponentScans(value = {
    @ComponentScan("pl.coderstrust.hibernate"),
})
public class AppConfig {

  @Autowired
  private Environment env;

  @Bean
  public DataSource getDataSource() {
    BasicDataSource dataSource = new BasicDataSource();
    dataSource.setDriverClassName(env.getProperty("dspring.datasource.driver-class-name"));
    dataSource.setUrl(env.getProperty("spring.datasource.url"));
    dataSource.setUsername(env.getProperty("spring.datasource.username"));
    dataSource.setPassword(env.getProperty("spring.datasource.password"));
    return dataSource;
  }

  @Bean
  public LocalSessionFactoryBean getSessionFactory() {
    LocalSessionFactoryBean factoryBean = new LocalSessionFactoryBean();
    factoryBean.setDataSource(getDataSource());

    Properties props = new Properties();
    props.put("spring.jpa.show-sql", env.getProperty("hibernate.show_sql"));
    props.put("spring.jpa.hibernate.ddl-auto", env.getProperty("hibernate.hbm2ddl.auto"));

    factoryBean.setHibernateProperties(props);
    factoryBean.setAnnotatedClasses(Foo.class);
    return factoryBean;
  }

  @Bean
  public HibernateTransactionManager getTransactionManager() {
    HibernateTransactionManager transactionManager = new HibernateTransactionManager();
    transactionManager.setSessionFactory(getSessionFactory().getObject());
    return transactionManager;
  }
}

完整堆栈跟踪:

Exception in thread "main" org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'invoiceController': Unsatisfied dependency expressed through field 'impl'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'invoiceServiceImpl': Unsatisfied dependency expressed through field 'dao'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'invoiceDaoImpl': Unsatisfied dependency expressed through field 'sessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'getSessionFactory' defined in pl.coderstrust.hibernate.AppConfig: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.orm.hibernate5.LocalSessionFactoryBean]: Factory method 'getSessionFactory' threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:588)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1264)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:866)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542)
    at org.springframework.context.annotation.AnnotationConfigApplicationContext.<init>(AnnotationConfigApplicationContext.java:84)
    at pl.coderstrust.Application.main(Application.java:24)
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'invoiceServiceImpl': Unsatisfied dependency expressed through field 'dao'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'invoiceDaoImpl': Unsatisfied dependency expressed through field 'sessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'getSessionFactory' defined in pl.coderstrust.hibernate.AppConfig: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.orm.hibernate5.LocalSessionFactoryBean]: Factory method 'getSessionFactory' threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:588)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1264)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585)
    ... 14 more
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'invoiceDaoImpl': Unsatisfied dependency expressed through field 'sessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'getSessionFactory' defined in pl.coderstrust.hibernate.AppConfig: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.orm.hibernate5.LocalSessionFactoryBean]: Factory method 'getSessionFactory' threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:588)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1264)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585)
    ... 27 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'getSessionFactory' defined in pl.coderstrust.hibernate.AppConfig: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.orm.hibernate5.LocalSessionFactoryBean]: Factory method 'getSessionFactory' threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:599)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1173)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1067)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:513)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585)
    ... 40 more
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.orm.hibernate5.LocalSessionFactoryBean]: Factory method 'getSessionFactory' threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:189)
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:588)
    ... 52 more
Caused by: java.lang.NullPointerException
    at java.util.Hashtable.put(Hashtable.java:459)
    at pl.coderstrust.hibernate.AppConfig.getSessionFactory(AppConfig.java:47)
    at pl.coderstrust.hibernate.AppConfig$$EnhancerBySpringCGLIB$$2fc92ee1.CGLIB$getSessionFactory$1(<generated>)
    at pl.coderstrust.hibernate.AppConfig$$EnhancerBySpringCGLIB$$2fc92ee1$$FastClassBySpringCGLIB$$3496d4d1.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228)
    at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:358)
    at pl.coderstrust.hibernate.AppConfig$$EnhancerBySpringCGLIB$$2fc92ee1.getSessionFactory(<generated>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:162)
    ... 53 more

Answer 1

查看 AppConfig#getSessionFactory 方法。当值的任一键为 null 时，java.util.Hashtable#put 会抛出 NPE。因此，您必须确保在运行应用程序时正确设置 hibernate.show_sql 和 hibernate.hbm2ddl.auto。