@Test
public void testAdd4() {
Session session = null;
try {
session = HibernateUtil.openSession();
session.beginTransaction();
Classroom c = new Classroom();
c.setGrade("2011");
c.setName("计算机");
// 此时classroom没有存，加了cascade="all" 会级联保存classroom
Student stu1 = new Student();
stu1.setClassroom(c);
stu1.setName("3243432");
session.save(stu1);
Student stu2 = new Student();
stu2.setClassroom(c);
stu2.setName("2234434432");
session.save(stu2);
session.getTransaction().commit();
} catch (Exception e) {
e.printStackTrace();
if (null != session) {
session.getTransaction().rollback();
}
} finally {
HibernateUtil.close(session);
}
}
@Test
public void testDeleted() {
Session session = null;
try {
session = HibernateUtil.openSession();
session.beginTransaction();
Student stu1 = (Student) session.get(Student.class, 10);
session.delete(stu1); // 报错，删除student会删除classroom,还有一个student依赖classroom
session.getTransaction().commit();
} catch (Exception e) {
e.printStackTrace();
if (null != session) {
session.getTransaction().rollback();
}
} finally {
HibernateUtil.close(session);
}
}
@Test
public void testLoad() {
Session session = null;
try {
session = HibernateUtil.openSession();
session.beginTransaction();
Student stu1 = (Student) session.load(Student.class, 1);
System.out.println(stu1.getName());
System.out.println(stu1.getClassroom().getName()); // 关联对象classroot也是延迟加载的
session.getTransaction().commit();
} catch (Exception e) {
e.printStackTrace();
if (null != session) {
session.getTransaction().rollback();
}
} finally {
HibernateUtil.close(session);
}
}