java - 未设置 'hibernate.dialect' 时连接不能为空

Question

在使用 spring3 设置 hibernate 时遇到更多问题。这次是说连接是空的，因为我的 hibernate.cfg.xml 文件中没有设置方言。

这里是完整的异常(exception):

    org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mySessionFactory' defined in URL [file:war/WEB-INF/datasource-config.xml]: Invocation of init method failed; nested exception is org.hibernate.HibernateException: Connection cannot be null when 'hibernate.dialect' not set
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1455)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:567)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:913)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:464)
    at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:96)
    at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:44)
    at org.springframework.test.context.TestContext.buildApplicationContext(TestContext.java:198)
    at org.springframework.test.context.TestContext.getApplicationContext(TestContext.java:233)
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:126)
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:85)
    at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:231)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:95)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.invokeTestMethod(SpringJUnit4ClassRunner.java:139)
    at org.junit.internal.runners.JUnit4ClassRunner.runMethods(JUnit4ClassRunner.java:51)
    at org.junit.internal.runners.JUnit4ClassRunner$1.run(JUnit4ClassRunner.java:44)
    at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:27)
    at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:37)
    at org.junit.internal.runners.JUnit4ClassRunner.run(JUnit4ClassRunner.java:42)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: org.hibernate.HibernateException: Connection cannot be null when 'hibernate.dialect' not set
    at org.hibernate.service.jdbc.dialect.internal.DialectFactoryImpl.determineDialect(DialectFactoryImpl.java:97)
    at org.hibernate.service.jdbc.dialect.internal.DialectFactoryImpl.buildDialect(DialectFactoryImpl.java:67)
    at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:172)
    at org.hibernate.service.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:75)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:159)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:131)
    at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:71)
    at org.hibernate.cfg.Configuration.buildSettingsInternal(Configuration.java:2270)
    at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:2266)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1735)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1775)
    at org.springframework.orm.hibernate4.LocalSessionFactoryBuilder.buildSessionFactory(LocalSessionFactoryBuilder.java:184)
    at org.springframework.orm.hibernate4.LocalSessionFactoryBean.afterPropertiesSet(LocalSessionFactoryBean.java:314)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1514)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1452)
    ... 29 more

这是我的 dataSource-config.xml 设置 session 工厂

    <?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-3.0.xsd
      ">


    <bean id="myDataSource" class="org.apache.commons.dbcp.BasicDataSource"
        destroy-method="close">
        <property name="driverClassName" value="${database.driver}" />
        <property name="url" value="${database.url}" />
        <property name="username" value="${database.user}" />
        <property name="password" value="${database.password} " />
    </bean>

    <bean id="mySessionFactory"
        class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
        <property name="dataSource" ref="myDataSource" />
        <property name="packagesToScan" value="com.jr.freedom"/>
        <property name="hibernateProperties" value="classpath:hibernate.cfg.xml"/>

    </bean>

    <!-- Declare a transaction manager -->
    <bean id="transactionManager"
        class="org.springframework.orm.hibernate3.HibernateTransactionManager"
        p:sessionFactory-ref="mySessionFactory" />

</beans>

下面是hibernate.cfg.xml文件

 <?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <!-- JDBC connection settings -->
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/freedom</property>
        <property name="hibernate.connection.username">root</property>
        <property name="hibernate.connection.password">password</property>

        <!-- JDBC connection pool, use Hibernate internal connection pool -->
        <property name="connection.pool_size">25</property>

        <!-- Defines the SQL dialect used in Hiberante's application -->
        <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>

        <!-- Enable Hibernate's automatic session context management -->
        <property name="current_session_context_class">thread</property>

        <!-- Disable the second-level cache  -->
        <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

        <!-- Display and format all executed SQL to stdout -->
        <property name="show_sql">true</property>
        <property name="format_sql">true</property>

        <!-- Drop and re-create the database schema on startup -->
        <property name="hbm2ddl.auto">create</property>

        <!-- Mapping to hibernate mapping files -->
        <!--mapping resource="org/kodejava/example/hibernate/app/Label.hbm.xml"/-->
    </session-factory>
</hibernate-configuration>

如您所见，方言正在设置中。

编辑:我的 database.properties 文件

    # DB properties file

database.url=jdbc:mysql://localhost:3306/freedom
database.driver=com.mysql.jdbc.Driver
database.user=root
database.password=password
database.maxConnections=25

编辑:这是一个完整的堆栈跟踪。访问数据库可能是问题，但我可以通过命令提示符成功访问它？

   2288 [main] WARN  org.hibernate.engine.jdbc.internal.JdbcServicesImpl  - HHH000342: Could not obtain connection to query metadata : Cannot create PoolableConnectionFactory (Access denied for user 'root'@'localhost' (using password: YES))
2289 [main] INFO  org.springframework.beans.factory.support.DefaultListableBeanFactory  - Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@4f549ceb: defining beans [org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping#0,org.springframework.format.support.FormattingConversionServiceFactoryBean#0,org.springframework.validation.beanvalidation.LocalValidatorFactoryBean#0,org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter#0,org.springframework.web.servlet.handler.MappedInterceptor#0,org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver#0,org.springframework.web.servlet.mvc.annotation.ResponseStatusExceptionResolver#0,org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver#0,org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping,org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter,org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter,org.springframework.web.servlet.config.viewControllerHandlerMapping,userService,myDataSource,mySessionFactory,transactionManager,propertyConfigurer,org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping#0,viewResolver,org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter#0,hello,userController,org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.annotation.internalPersistenceAnnotationProcessor,org.springframework.context.annotation.ConfigurationClassPostProcessor$ImportAwareBeanPostProcessor#0]; root of factory hierarchy
2289 [main] DEBUG org.springframework.beans.factory.support.DisposableBeanAdapter  - Invoking destroy method 'close' on bean with name 'myDataSource'
2289 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory  - Retrieved dependent beans for bean '(inner bean)#14': [org.springframework.web.servlet.config.viewControllerHandlerMapping]
2289 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory  - Retrieved dependent beans for bean '(inner bean)#8': [org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver#0]
2289 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory  - Retrieved dependent beans for bean '(inner bean)#1': [org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter#0]
2290 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory  - Retrieved dependent beans for bean '(inner bean)': [org.springframework.web.servlet.handler.MappedInterceptor#0]

Answer 1

数据库连接丢失。在 hibernate.cfg.xml 文件中添加这样的行

<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">
    jdbc:mysql://localhost:3306/your_database
</property>
<property name="connection.username">your_user</property>
<property name="connection.password">your_password</property>

(如果您的计算机上没有安装数据库，则替换 localhost，并在我的示例中设置以 your_ 开头的值。