Student<------>Course:
1.Student.hbm.xml:
<hibernate-mapping package="com.buaa.hibernate.bean"> <class name="Student"> <id name="id" column="id"> <generator class="native"></generator> </id> <property name="sname" column="stu_name"></property> <set name="courses" table="stu_course" inverse="true"> <key column="stu_id"></key> <many-to-many class="Course" column="course_id"></many-to-many> </set> </class> </hibernate-mapping>
2.Course.hbm.xml:
<hibernate-mapping package="com.buaa.hibernate.bean"> <class name="Course"> <id name="id" column="id"> <generator class="native"></generator> </id> <property name="cname" column="course_name"></property> <set name="students" table="stu_course"> <key column="course_id"></key> <many-to-many class="Student" column="stu_id"></many-to-many> </set> </class> </hibernate-mapping>
☆☆☆ 注意：inverse属性：只能有一个设置为true。也不能都不设置，否则会报异常（
1、Duplicate entry'2-2' for key 'PRIMARY'；
2、Could notsynchronize database state with session；
2、ConstrainViolationException:Could not execute JDBC batch update；）
3.Test测试类：
public class Test extends TestCase {
public void testMTM(){
//MySessionFactory是自己写的一个类，获取session
Session session = MySessionFactory.getSession(0);
Student stu = new Student();
stu.setSname("jack");
Student stu2 = new Student();
stu2.setSname("simon");
Course course = new Course();
course.setCname("English");
Course course2 = new Course();
course2.setCname("Math");
Set<Course> courses = new HashSet<Course>();
courses.add(course);
courses.add(course2);
Set<Student> students = new HashSet<Student>();
students.add(stu);
students.add(stu2);
stu.setCourses(courses);
stu2.setCourses(courses);
course.setStudents(students);
course2.setStudents(students);
session.save(course);
session.save(course2);
session.save(stu);
session.save(stu2);
session.beginTransaction().commit();
session.close();
}
}
4.控制台输出：
Hibernate: insert into Course (course_name) values (?) Hibernate: insert into Course (course_name) values (?) Hibernate: insert into Student (stu_name) values (?) Hibernate: insert into Student (stu_name) values (?) Hibernate: insert into stu_course (course_id,stu_id) values (?,?) Hibernate: insert into stu_course (course_id,?)
