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java - 获取异常 java.lang.IllegalStateException: EntityManagerFactory is closed while trying to save secound istance

问题描述

我正在学习休眠。开始时一切都很清楚，但是当我尝试运行我的应用程序时，我主要有两个与会话相关的操作，但出现异常：

java.lang.IllegalStateException: EntityManagerFactory is closed

您可以在下面找到我的 DBManager 类，其中我有将实例添加到 DB 的方法：

import org.hibernate.Session;

public class DBManager
{
    public void addAutor(String name, String lastName, Book book)
    {
        Session session = HibernateUtil.getSessionFactory().openSession();
        session.beginTransaction();
        Autor autor = new Autor(name,lastName,book);
        session.save(autor);
        session.getTransaction().commit();
        HibernateUtil.getSessionFactory().close();
    }
    public Book addBook(int ISBN, String name, String autorName)
    {
        Session session = HibernateUtil.getSessionFactory().openSession();
        session.beginTransaction();
        Book book = new Book(ISBN,name,autorName);
        session.save(book);
        session.getTransaction().commit();
        HibernateUtil.getSessionFactory().close();
        return book;
    }
}

这是我用于配置会话的 HibernateUtil 类：

import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;

public class HibernateUtil {

    private static final SessionFactory sessionFactory = buildSessionFactory();

    private static SessionFactory buildSessionFactory() {
        try {
            Configuration configuration = new Configuration();
            configuration.addAnnotatedClass(Autor.class);
            configuration.addAnnotatedClass(Book.class);
            configuration.configure();

            StandardServiceRegistryBuilder standardServiceRegistryBuilder = new StandardServiceRegistryBuilder();
            standardServiceRegistryBuilder.applySettings(configuration.getProperties());
            ServiceRegistry serviceRegistry = standardServiceRegistryBuilder.build();

            return configuration.buildSessionFactory(serviceRegistry);
        }
        catch(Exception e) {
            throw new ExceptionInInitializerError(e);
        }
    }

    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }
}

最后是主要课程：

public class Test
{

    public static void main (String args[])
    {
        DBManager dbManager = new DBManager();
        Book book =  dbManager.addBook(1,"Hobbit","Tolkien");
        dbManager.addAutor("JRR","Tolkien",book);
    }
}

正如你所看到的，我只是放书，而不是尝试放 Autor。第二种方法异常的原因可能是什么？我想我会做某事。关闭和打开会话时出错，但是我不知道出了什么问题。

标签： javamysqlhibernate

解决方案

I found the sulution myself:

I have created the one sessionFactory object for whole class DBManager:

private final SessionFactory sessionFactory = HibernateUtil.getSessionFactory();

So in every method I open session, and than close at the end, eg:

    public void addAutor(String name, String lastName, Book book)
    {
        Session session=sessionFactory.openSession();
        session.beginTransaction();
        Autor autor = new Autor(name,lastName,book);
        session.save(autor);
        session.getTransaction().commit();
        session.close();
    }

Maybe someone will face the same problem.

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