hibernate升級到5.x時丟棄了一部分相關的api，目前網上版本眾多，從外網上找到了一個能用的。別的看不懂。
轉載 https://codingtechroom.com/question/how-to-retrieve-all-table-names-from-sessionfactory-in-hibernate

import org.hibernate.SessionFactory;
import org.hibernate.boot.Metadata;
import org.hibernate.boot.MetadataSources;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.mapping.Table;

import java.util.Set;

public class HibernateUtil {
    private static SessionFactory sessionFactory;

    static {
        try {
            StandardServiceRegistry standardRegistry = new StandardServiceRegistryBuilder()
                .configure().build();
            Metadata metaData = new MetadataSources(standardRegistry)
                .buildMetadata();
            sessionFactory = metaData.buildSessionFactory();
        } catch (Throwable ex) {
            throw new ExceptionInInitializerError(ex);
        }
    }

    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }

    public static void listTableNames() {
        Set<Table> tables = sessionFactory.getStatistics().getEntityNames();
        for (Table table : tables) {
            System.out.println(table.getName());
        }
    }
}

另外這個頁面幫助比較大(將 Hibernate 從 4.3.x 遷移到 5.x，針對方法 org.hibernate.cfg.Configuration.getClassMapping(className))：
https://dev59.com/P1wY5IYBdhLWcg3wTWMu
其中的這篇回答:
在Hibernate 5中，可以像這樣初始化元數據：

URL configFileURL = getResource(); //some method to get hold of the location of your hibernate.cfg.xml
StandardServiceRegistry standardRegistry = new StandardServiceRegistryBuilder().configure(configFileURL).build();
Metadata metaData = new MetadataSources(standardRegistry).getMetadataBuilder().build();

并使用元數據上的getEntityBindings()

Collection<PersistentClass> entityBindings = metadata.getEntityBindings();
Iterator<PersistentClass> iterator = entityBindings.iterator();
  while (iterator.hasNext()) {
    PersistentClass persistentClass = iterator.next();    
    //do somthing
  }