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I'm learning Java EE and Hibernate, and I've run into the following problem:

I've created a Dynamic Web Project in Eclipse, I've converted it into a MAVEN project, added the mysql-connector-java and the hibernate-core dependencies to the pom.xml. I've added a servlet, and in the doGet method, I've tried to initialize the sessionfactory to create the tables. I'm using tomcat.

When I'm making a request to the servlet I'm getting the following exception:

org.hibernate.HibernateException: Dialect class not found:   org.hibernate.dialect.MYSQLDialect
 org.hibernate.service.jdbc.dialect.internal.DialectFactoryImpl.constructDialect(DialectFactoryImpl.java:77)
org.hibernate.service.jdbc.dialect.internal.DialectFactoryImpl.buildDialect(DialectFactoryImpl.java:65)
org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:146)
org.hibernate.service.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:76)
org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:160)
org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:132)
org.hibernate.cfg.Configuration.buildTypeRegistrations(Configuration.java:1818)
org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1776)
hu.adamsan.testhibernate.TestHibernate.doGet(TestHibernate.java:74)

pom.xml:

dependencies>
    <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.26</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>4.2.6.Final</version>
        </dependency>
</dependencies>

I've tried to look into the Maven Dependencies, org.hibernate.dialect.MySQLDialect.class is in there, in the location: getServletContext().getRealPath(".") ->E:\eclips_jee\workspace.metadata.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\TestHibernateWeb\ , in the WEB-INF\lib directory, there is hibernate-core-4.2.6.Final.jar, when I opened it with 7zip, I could find inside the org/hibernate/dialect/MySQL5Dialect.class.

What am I missing? I really have no idea.

doGet method:

    PrintWriter w = response.getWriter();
    w.println("Testing hibernate<br/>");
    w.println(getServletContext().getRealPath(".")+"<br/>");

    Configuration config;
    ServiceRegistry registry;
    SessionFactory factory;     
    config = new Configuration().addAnnotatedClass(Modell.class);       
    Properties props = getProperties();     
    props.setProperty(Environment.HBM2DDL_AUTO, "create");      
    config.setProperties(props);        
    registry = new ServiceRegistryBuilder().applySettings(props).buildServiceRegistry();        
    factory = config.buildSessionFactory(registry);     
    factory.close();
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2 回答 2

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答案就在问题中。你已经在你的 jar 文件中找到了MySQLDialect，MySQL5Dialect但是你的配置文件试图使用MYSQLDialect. Java 区分大小写。

于 2013-10-06T07:30:19.277 回答
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我之所以这么说是因为上面的答案对我来说并不准确，在我的情况下，我使用的是 Intellij IDEA 在使用 Hibernate 依赖项时，我过度使用类型（pom 类型）配置 pom 依赖项我的解决方案是删除它类型。

<!--        Hibernate JPA dependency -->
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>5.6.3.Final</version>
        <type>pom</type>
    </dependency>

工作版本是：

<!--        Hibernate JPA dependency -->
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>5.6.3.Final</version>
    </dependency>

无 POM 类型

这可以解决以下错误：

java.lang.TypeNotPresentException：类型 org.hibernate.SessionFactory 不存在 ，这通常会阻止以下属性的解析， <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop> 因此在 spring 框架下设置休眠会话工厂时

于 2022-02-23T23:42:52.953 回答