创建名为“sessionFactory”

Question

嗨，我是春天的初学者，如果这个问题是基本的，那就很抱歉。我使用的是Spring 4.3.4，Hibernate 5.0.3以及MySQL。我明白了：

Error creating bean with name 'sessionFactory' defined in class path resource [english/config/HibernateConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.orm.hibernate5.LocalSessionFactoryBean]: Factory method 'sessionFactory' 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:1128)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1022)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:512)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
    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:735)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:866)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:444)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:326)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:107)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4853)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5314)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:753)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:729)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:717)
    at org.apache.catalina.startup.HostConfig.manageApp(HostConfig.java:1696)
    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.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:300)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
    at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
    at org.apache.catalina.mbeans.MBeanFactory.createStandardContext(MBeanFactory.java:484)
    at org.apache.catalina.mbeans.MBeanFactory.createStandardContext(MBeanFactory.java:433)
    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.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:300)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
    at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
    at javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1468)
    at javax.management.remote.rmi.RMIConnectionImpl.access$300(RMIConnectionImpl.java:76)
    at javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1309)
    at javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1401)
    at javax.management.remote.rmi.RMIConnectionImpl.invoke(RMIConnectionImpl.java:829)
    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 sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:324)
    at sun.rmi.transport.Transport$1.run(Transport.java:200)
    at sun.rmi.transport.Transport$1.run(Transport.java:197)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.Transport.serviceCall(Transport.java:196)
    at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:568)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:826)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:683)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:682)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.orm.hibernate5.LocalSessionFactoryBean]: Factory method 'sessionFactory' 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)
    ... 59 more
Caused by: java.lang.NullPointerException
    at java.util.Hashtable.put(Hashtable.java:459)
    at java.util.Properties.setProperty(Properties.java:166)
    at english.config.HibernateConfig$1.<init>(HibernateConfig.java:61)
    at english.config.HibernateConfig.hibernateProperties(HibernateConfig.java:59)
    at english.config.HibernateConfig.sessionFactory(HibernateConfig.java:32)
    at english.config.HibernateConfig$$EnhancerBySpringCGLIB$$87c4dc1a.CGLIB$sessionFactory$0(<generated>)
    at english.config.HibernateConfig$$EnhancerBySpringCGLIB$$87c4dc1a$$FastClassBySpringCGLIB$$e2253ad2.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228)
    at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:356)
    at english.config.HibernateConfig$$EnhancerBySpringCGLIB$$87c4dc1a.sessionFactory(<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)
    ... 60 more

这是我的 HibernateConfig：

@Configuration
@EnableTransactionManagement
public class HibernateConfig {

    @Autowired
    Environment env;

    @Bean
    public LocalSessionFactoryBean sessionFactory() throws PropertyVetoException {
        LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean();
        sessionFactory.setDataSource(restDataSource());
        sessionFactory.setPackagesToScan("english.entity");
        sessionFactory.setHibernateProperties(hibernateProperties());
        return sessionFactory;
    }

    @Bean
    public ComboPooledDataSource restDataSource() throws PropertyVetoException{
        ComboPooledDataSource dataSource = new ComboPooledDataSource();
        dataSource.setDriverClass(env.getProperty("jdbc.driverClassName"));
        dataSource.setJdbcUrl(env.getProperty("jdbc.url"));
        dataSource.setUser(env.getProperty("jdbc.user"));
        dataSource.setPassword(env.getProperty("jdbc.pass"));
        return dataSource;
    }

    @Bean
    @Autowired
    public HibernateTransactionManager transactionManager(
            SessionFactory sessionFactory) {

        HibernateTransactionManager txManager
                = new HibernateTransactionManager();
        txManager.setSessionFactory(sessionFactory);

        return txManager;
    }

    Properties hibernateProperties() {
        return new Properties() {
            {
                setProperty("hibernate.hbm2ddl.auto",
                        env.getProperty("hibernate.hbm2ddl.auto"));
                setProperty("hibernate.dialect",
                        env.getProperty("hibernate.dialect"));
                setProperty("hibernate.globally_quoted_identifiers",
                        "true");
            }
        };
    }
}

这是我的 hibernate.properties

# jdbc.X
jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/english?createDatabaseIfNotExist=true
jdbc.user=user
jdbc.pass=pass

# hibernate.X
hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
hibernate.show_sql=false
hibernate.hbm2ddl.auto=update

Answer 1

异常是由于环境没有这样的属性而且语句env.getProperty(...)返回null，这被设置为值是不可能的。

确保Spring加载了hibernate.properties文件。或者将此属性移动到application.properties文件。