Caused by: java.lang.ClassNotFoundException: Could not load requested class : com.mysql.jdbc.Driver

一、报错问题

二、问题背景

新建Java项目，并添加 Hibernate 框架支持，启动测试（运行默认的Main类中的main()方法），出现报错。

Main.java

import org.hibernate.HibernateException;import org.hibernate.Metamodel;import org.hibernate.query.Query;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.cfg.Configuration;import javax.persistence.metamodel.EntityType;import java.util.Map;public class Main {private static final SessionFactory ourSessionFactory;static {try {Configuration configuration = new Configuration();configuration.configure();ourSessionFactory = configuration.buildSessionFactory();} catch (Throwable ex) {throw new ExceptionInInitializerError(ex);}}public static Session getSession() throws HibernateException {return ourSessionFactory.openSession();}public static void main(final String[] args) throws Exception {final Session session = getSession();try {System.out.println("querying all the managed entities...");final Metamodel metamodel = session.getSessionFactory().getMetamodel();for (EntityType<" />> entityType : metamodel.getEntities()) {final String entityName = entityType.getName();final Query query = session.createQuery("from " + entityName);System.out.println("executing: " + query.getQueryString());for (Object o : query.list()) {System.out.println("" + o);}}} finally {session.close();}}}