其他未给出代码，请参考上一篇....

一.数据的删除

方法1.从“多”的一方进行数据的删除

books.hbm.xml文件不变：

publishers.hbm.xml文件：

在MyHibernateDao.java中添加如下代码：

public Books getBook(int Id){        Books book = null;        Session session = HibernateSessionFactory.getSession();        Transaction tran = session.beginTransaction();        book = (Books)session.get(Books.class, new Integer(Id));        tran.commit();        return book;    }        public void deleteBook(Books book){        Session session = HibernateSessionFactory.getSession();        Transaction tran = session.beginTransaction();        session.delete(book);        tran.commit();    }

在HibernateServlet.java中添加如下代码

Books book1 = dao.getBook(3);        book1.getPublishers().getBooks().remove(book1);        book1.setPublishers(null);        dao.deleteBook(book1);

注意如果没有book1.getPublishers().getBooks().remove(book1); book1.setPublishers(null);这两句，会出现 org.hibernate.ObjectDeletedException: deleted object would be re-saved by cascade (remove deleted object from associations)这个异常，主要是因为Books和Publishers二者的级联关系。

所以我们可以先将级联断开，然后再进行删除“多”的一方。

方法2.从“一”的这一方进行删除，这样的话就是和“一”这一方相关联的“多”的一方都会被删除

在HibernateServlet.java中添加如下代码：

Publishers publisher = dao.getPublisher(1);dao.deletePublisher(publisher);

publishers.hbm.xml 和 books.hbm.xml 不用改变

在MyHibernateDao.java中添加如下代码：

public Publishers getPublisher(int Id){        Publishers publisher = null;        Session session = HibernateSessionFactory.getSession();        Transaction tran = session.beginTransaction();        publisher = (Publishers)session.get(Publishers.class, new Integer(Id));        tran.commit();        return publisher;    }        public void deletePublisher(Publishers publisher){        Session session = HibernateSessionFactory.getSession();        Transaction tran = session.beginTransaction();        session.delete(publisher);        tran.commit();    }

二.数据的删除

在MyHibernateDao.java中添加如下代码：

public void updateBooks(Books book){        Session session = HibernateSessionFactory.getSession();        Transaction tran = session.beginTransaction();        session.update(book);        tran.commit();    }

在HibernateServlet.java中添加如下代码

//更改数据， 更改对应的外键        Books book1 = dao.getBook(79);//将book1的publisherId替换成46        /较为安全的写法，然而并不知道有什么卵用        Publishers px = dao.getPublisher(book1.getPublishers().getPublisherId());        px.getBooks().remove(book1);        Publishers py = dao.getPublisher(46);        py.getBooks().add(book1);        /        book1.setPublishers(py);        dao.updateBooks(book1);                //更改数据，Books        Books book2 = dao.getBook(79);        book2.setTitle("如何成为成功的人士");        dao.updateBooks(book2);

其他不变....