hibernate根据字段生成数据库表

package test;   
  
import java.io.File;   
  
import org.hibernate.HibernateException;   
import org.hibernate.Session;   
import org.hibernate.SessionFactory;   
import org.hibernate.Transaction;   
import org.hibernate.cfg.Configuration;   
import org.hibernate.tool.hbm2ddl.SchemaExport;   
  
public class HibernateSchemaExport ...{   
  
    static Session session;   
  
    static Configuration config = null;   
    static Transaction tx = null;   
  
    public static void main(String[] args) ...{   
        /** *//**  
         * 根据映射文件创建数据库结构  
         */  
        try ...{   
            config = new Configuration().configure(new File(   
                    "src/hibernate.cfg.xml"));   
  
            System.out.println("Creating tables...");   
  
            SessionFactory sessionFactory = config.buildSessionFactory();   
            session = sessionFactory.openSession();