hibernate的基础学习--多对多关联
多对多采用学生老师模型进行测试
学生配置文件：
1 <?xml version="1.0" encoding="utf-8" ?> 2 <!DOCTYPE hibernate-mapping PUBLIC 3 "-//Hibernate/Hibernate Mapping DTD 3.0//EN" 4 "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> 5 <!-- 映射配置 --> 6 <hibernate-mapping> 7 <class name="hib.po.Student" table="t_student"> 8 <id name="stuId" column="stu_id"> 9 <generator class="uuid"></generator> 10 </id> 11 <property name="stuName" column="stuname"></property> 12 13 <!-- 和老师的关联关系：teachers 14 name：关联关系属性名称 15 table：中间表名称 16 inverse：关联关系的维护权 17 cascade:级联 delete update 18 --> 19 <set name="teachers" table="t_stu_tea"> 20 <!--column:中间表中指向当前模型对应表(t_student)的外键名--> 21 <key column="stu_id"></key> 22 <!-- 23 class：关联关系字段集合的元素的类型 24 column:中间表指向当前模型关联的模型对应表（t_student）的外键 25 --> 26 <many-to-many class="hib.po.Teacher" column="tea_id"></many-to-many> 27 </set> 28 </class> 29 </hibernate-mapping>
老师配置文件：
1 <?xml version="1.0" encoding="utf-8" ?> 2 <!DOCTYPE hibernate-mapping PUBLIC 3 "-//Hibernate/Hibernate Mapping DTD 3.0//EN" 4 "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> 5 <!-- 映射配置 --> 6 <hibernate-mapping> 7 <class name="hib.po.Teacher" table="t_teacher"> 8 <id name="teaId" column="tea_id"> 9 <generator class="uuid"></generator> 10 </id> 11 <property name="teaName" column="teaname"></property> 12 13 <!-- 和学生的关联关系：students 14 name：关联关系属性名称 15 table：中间表名称（必须和对应关联表中配置一致） 16 放弃维护关系 inverse="true" 17 --> 18 <set name="students" table="t_stu_tea"> 19 <!--column:中间表中指向当前模型对应表（t_teacher)的外键名--> 20 <key column="tea_id"></key> 21 22 <!-- 23 class：关联关系字段集合的元素的类型 24 column:中间表指向当前模型关联的模型对应表（t_student）的外键 25 --> 26 <many-to-many class="hib.po.Student" column="stu_id"></many-to-many> 27 </set> 28 </class> 29 </hibernate-mapping>
测试方法：
1 public class TestHibernate { 2 3 /** 4 * 添加数据记录 5 */ 6 @Test 7 public void addTeacherStudent() { 8 SessionFactory sf = H3Util.getSessionFactory(); 9 Session session = sf.openSession(); 10 Transaction ts = session.beginTransaction(); 11 12 Student stu1 = new Student(null, "张三", null); 13 Student stu2 = new Student(null, "李四", null); 14 15 Teacher tea1 = new Teacher(null, "张老师", null); 16 Teacher tea2 = new Teacher(null, "李老师", null); 17 18 19 session.save(stu1); 20 session.save(stu2); 21 session.save(tea1); 22 session.save(tea2); 23 24 ts.commit(); 25 session.close(); 26 } 27 @Test /* 关联关系*/ 28 public void updateStudent() { 29 SessionFactory sf = H3Util.getSessionFactory(); 30 Session session = sf.openSession(); 31 Transaction ts = session.beginTransaction(); 32 33 Teacher t1 = (Teacher) session.get(Teacher.class, "4028810a57d19c510157d19c55650002"); 34 Student s1 = (Student) session.get(Student.class, "4028810a57d19c510157d19c554a0000"); 35 Student s2 = (Student) session.get(Student.class, "4028810a57d19c510157d19c55650001"); 36 Set<Teacher> st1 = s1.getTeachers(); 37 st1.add(t1); 38 Set<Teacher> st2 = s2.getTeachers(); 39 st2.add(t1); 40 s1.setTeachers(st1); 41 s2.setTeachers(st2); 42 session.update(s1); 43 session.update(s2); 44 45 ts.commit(); 46 session.close(); 47 } 48 @Test 49 public void delStudent1() { 50 SessionFactory sf = H3Util.getSessionFactory(); 51 Session session = sf.openSession(); 52 Transaction ts = session.beginTransaction(); 53 54 //张三 55 Student stu = (Student) session.get(Student.class, "4028810a57d19c510157d19c554a0000"); 56 57 //先删除关联关系（中间表字段）再删除本对象 58 session.delete(stu); 59 60 ts.commit(); 61 session.close(); 62 } 63 64 }
