我在以下环境中有一个Web应用程序。
我在application-context.xml文件中的配置如下所示。
<?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:aop="http://www.springframework.org/schema/aop"
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-2.5.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/social_networking?zeroDateTimeBehavior=convertToNull" />
<property name="username" value="root" />
<property name="password" value="root" />
</bean>
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="persistenceUnitName" value="WebAppPU"/>
<property name="dataSource" ref="dataSource" />
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<property name="showSql" value="true"/>
<property name="generateDdl" value="true"/>
<property name="databasePlatform" value="org.hibernate.dialect.HSQLDialect"/>
</bean>
</property>
<property name="jpaDialect">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect" />
</property>
</bean>
<bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor"/>
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory"/>
</bean>
<tx:annotation-driven transaction-manager="transactionManager"/>
<bean id="testDAOService" class="admin.dao.TestDAO"/>
</beans>
persistence.xml包含以下xml。
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="WebAppPU" transaction-type="RESOURCE_LOCAL">
<!--<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>-->
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<class>model.Test</class>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/social_networking?zeroDateTimeBehavior=convertToNull"/>
<property name="javax.persistence.jdbc.password" value="root"/>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
<property name="javax.persistence.jdbc.user" value="root"/>
<!--<property name="hibernate.hbm2ddl.auto" value="create-drop"/>-->
</properties>
</persistence-unit>
</persistence>
以下是目前唯一的实体类。我试图用这个已经成功的实体执行插入操作。
package model;
@Entity
public class Test implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "id", nullable = false)
private Integer id;
@Column(name = "description", length = 45)
private String description;
private static final long serialVersionUID = 1L;
public Test() {}
public Test(Integer id) {
this.id = id;
}
// Getters and setter.
}
虽然应用程序运行，但在服务器控制台上可以看到以下异常。
ERROR: HHH000299: Could not complete schema update
java.lang.NullPointerException
at org.hibernate.tool.hbm2ddl.DatabaseMetadata.initSequences(DatabaseMetadata.java:156)
at org.hibernate.tool.hbm2ddl.DatabaseMetadata.<init>(DatabaseMetadata.java:70)
at org.hibernate.tool.hbm2ddl.DatabaseMetadata.<init>(DatabaseMetadata.java:63)
at org.hibernate.tool.hbm2ddl.SchemaUpdate.execute(SchemaUpdate.java:196)
at org.hibernate.tool.hbm2ddl.SchemaUpdate.execute(SchemaUpdate.java:178)
at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:505)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1742)
at org.hibernate.ejb.EntityManagerFactoryImpl.<init>(EntityManagerFactoryImpl.java:94)
at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:905)
at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:890)
at org.hibernate.ejb.HibernatePersistence.createContainerEntityManagerFactory(HibernatePersistence.java:74)
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:288)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:310)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1547)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1485)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:524)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:461)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1117)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:922)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:389)
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:294)
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:112)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4797)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5291)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3926)
at org.apache.catalina.manager.ManagerServlet.reload(ManagerServlet.java:954)
at org.apache.catalina.manager.ManagerServlet.doGet(ManagerServlet.java:364)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:108)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:581)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:1822)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)
尝试在persistence.xml文件中使用以下属性但没有帮助。
<property name="hibernate.hbm2ddl.auto" value="update"/>
可能是什么原因？
答案 0 :(得分：10)
看起来你错误地混合了Hibernate方言和数据库。在您的原始问题中，您有一个MySQL数据库和一个org.hibernate.dialect.HSQLDialect的方言（参见下面的第一个代码块）。
在您的解决方案中，您拥有MySQL数据库和正确的org.hibernate.dialect.MySQL5Dialect方言（请参阅下面的第二个代码块）。
如果您已将原版中的databasePlatform更改为MySQL方言，那么它也会起作用。
原件：
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
...
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
...
<property name="databasePlatform" value="org.hibernate.dialect.HSQLDialect"/>
</bean>
</property>
...
</bean>
工作：
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="WebAppPU" transaction-type="RESOURCE_LOCAL">
...
<properties>
...
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
...
</properties>
</persistence-unit>
</persistence>
答案 1 :(得分：2)
就我而言，原因是磁盘空间不足。
我在OpenShift上有一个实例，并且第一个JDBC开始抛出一些异常，因为MySQL已关闭，用垃圾填充日志，最后填满了磁盘。
答案 2 :(得分：0)
当我坚持使用JNDI查找时，问题就消失了。因此，在context.xml文件中，我定义了一个像
<?xml version="1.0" encoding="UTF-8"?>
<Context antiJARLocking="true" path="/WebApp">
<Resource name="jdbc/social_networking"
auth="Container"
type="javax.sql.DataSource"
maxActive="100"
maxIdle="30"
maxWait="10000"
username="root"
password="root"
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/social_networking"/>
</Context>
需要在web.xml文件中定义资源引用，例如
<resource-ref>
<res-ref-name>jdbc/social_networking</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
此数据源在persistence.xml文件中引用如下。
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="WebAppPU" transaction-type="RESOURCE_LOCAL">
<!--<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>-->
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<non-jta-data-source>java:comp/env/jdbc/social_networking</non-jta-data-source>
<class>model.Test</class>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties>
<property name="hibernate.connection.datasource" value="java:comp/env/jdbc/social_networking"/>
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
<property name="hibernate.show_sql" value="true" />
<property name="hibernate.format_sql" value="true" />
<property name="hibernate.ejb.naming_strategy" value="org.hibernate.cfg.ImprovedNamingStrategy"/>
</properties>
</persistence-unit>
</persistence>
最后，application-context.xml文件已修改如下。
<?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:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:jee="http://www.springframework.org/schema/jee"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd
http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">
<context:component-scan base-package="admin.mangedbean converter" use-default-filters="false">
<context:include-filter expression="org.springframework.stereotype.Controller" type="annotation"/>
<context:include-filter expression="org.springframework.web.bind.annotation.ControllerAdvice" type="annotation"/>
</context:component-scan>
<mvc:annotation-driven/>
<context:annotation-config/>
<bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor"/>
<bean class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean" id="entityManagerFactory" >
<property name="jpaProperties">
<props>
<prop key="hibernate.enable_lazy_load_no_trans">false</prop>
<!-- I use fetch joins or queries/subqueries with a desired/required list of columns only for lazily loaded collections, when they are required to be fetched from outside of an active transaction boundary.
Therefore it is set to false. -->
</props>
</property>
<property name="jpaPropertyMap">
<map>
<entry key="eclipselink.weaving" value="false"/>
</map>
</property>
<property name="loadTimeWeaver">
<bean class="org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver"/>
</property>
</bean>
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory"/>
</bean>
<tx:annotation-driven transaction-manager="transactionManager"/>
<bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
<property name="jndiName" value="java:comp/env/jdbc/social_networking"/>
</bean>
<!--Bean registration-->
<bean id="testService" class="admin.dao.TestDAO"/>
</beans>
答案 3 :(得分：-1)
请检查实体表是否存在。
如果存在则会出现以下属性的错误。
<property name="hibernate.hbm2ddl.auto" value="update"/>
将其更改为
<property name="hibernate.hbm2ddl.auto" value="create"/>
这将创建新的实体表。