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Java 如何为Hibernate动态加载驱动程序?_Java_Hibernate_Jdbc - Fatal编程技术网

Java 如何为Hibernate动态加载驱动程序?

Java 如何为Hibernate动态加载驱动程序?,java,hibernate,jdbc,Java,Hibernate,Jdbc,我正在为JDBC动态加载驱动程序。它工作正常,但是当我尝试打开hibernate会话时,这个DriverManager就变得无用了 org.hibernate.service.classloading.spi.ClassLoadingException: Specified JDBC Driver com.mysql.jdbc.Driver could not be loaded 这是密码 public class TestHibernateSessionFactory {

我正在为JDBC动态加载驱动程序。它工作正常,但是当我尝试打开hibernate会话时,这个
DriverManager
就变得无用了

org.hibernate.service.classloading.spi.ClassLoadingException: Specified JDBC Driver com.mysql.jdbc.Driver could not be loaded 
这是密码

    public class TestHibernateSessionFactory {


        public void test() throws MalformedURLException, InstantiationException, IllegalAccessException, ClassNotFoundException, SQLException { 
        URL u = new URL("jar:file:/C:\\Users\\...\\mysql-connector-java-5.1.40-bin.jar!/");
        String classname = "com.mysql.jdbc.Driver";
        URLClassLoader ucl = new URLClassLoader(new URL[] { u });
        Driver d = (Driver)Class.forName(classname, true, ucl).newInstance();
        DriverManager.registerDriver(new DriverLoader(d));


        Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306", "admin", "password"); 

    // this is the proof that DriverManager loaded and works fine
        System.out.println("CONNECTION OBJECT WORKS FINE: " + con);

    // Now I want to try this same technique with hibernate     
        Session session = null; 
        Transaction tx = null; 

        SessionFactory sf = buildSessionFactory("jdbc:mysql://localhost:3306", "admin", "password"); 

// ERROR  Specified JDBC Driver com.mysql.jdbc.Driver could not be loaded  WHY ??? 
            session = sf.openSession(); 
            System.out.println(session);     
        }

        private static SessionFactory buildSessionFactory(String myUrl, String myUser, String myPass) {

            Configuration configuration = new Configuration();
            configuration.configure();

            configuration.setProperty("hibernate.connection.url", myUrl);
            configuration.setProperty("hibernate.connection.username", myUser);
            configuration.setProperty("hibernate.connection.password", myPass); 
            configuration.setProperty("hibernate.connection.driver_class", "com.mysql.jdbc.Driver"); 
            configuration.setProperty("hibernate.hbm2ddl.auto", "create-drop"); 

            ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().applySettings(configuration.getProperties()).buildServiceRegistry(); 

            return configuration.buildSessionFactory(serviceRegistry);
    }

    }
两个问题:

  • 为什么它不适用于hibernate,而适用于jdbc
  • 如何修复它

  • 答案是Hibernate将尝试从上下文(当前线程)类加载器加载驱动程序,但它没有驱动程序。第一部分之所以有效,是因为您使用具有驱动程序的类加载器来创建连接


    解决方案可以是使用操作上下文类加载器。当使用加载的驱动程序的方法退出时,不要忘记清理它

    解决问题的方法可能是这样的:

    想法是在初始化
    Hibernate SessionFactory

    像这样:

    Thread.currentThread().setContextClassLoader(myOwnClassLoader);
    
    虽然这不是解决您的问题的最佳解决方案之一,但事实就是如此。虽然这是一个不完整的讨论,但它仍然非常有用,可以为您提供继续进行的指导


    希望这有帮助

    非常感谢你。请分享一些代码参考,看看乔布斯的答案,这可能会帮助你谢谢。这是一个真实的答案