Student.java
1 package cn.itcast.hiberate.sh.domain;
2
3 import java.util.Set;
4
5 public class Student {
6 private Long sid;
7 private String sname;
8 private String description;
9 Set<Course> courses;
10
11
12 public Set<Course> getCourses() {
13 return courses;
14 }
15 public void setCourses(Set<Course> courses) {
16 this.courses = courses;
17 }
18 public Long getSid() {
19 return sid;
20 }
21 public void setSid(Long sid) {
22 this.sid = sid;
23 }
24 public Student(String sname, String description) {
25 super();
26 this.sname = sname;
27 this.description = description;
28 }
29 public Student() {
30 // TODO Auto-generated constructor stub
31 }
32 public String getSname() {
33 return sname;
34 }
35 public void setSname(String sname) {
36 this.sname = sname;
37 }
38 public String getDescription() {
39 return description;
40 }
41 public void setDescription(String description) {
42 this.description = description;
43 }
44
45 }
Student.hbm.xml
1 <?xml version="1.0" encoding="utf-8"?>
2 <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
3 "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
4 <hibernate-mapping>
5 <class name="cn.itcast.hiberate.sh.domain.Student">
6 <id name="sid" length="5">
7 <generator class="increment"></generator>
8 </id>
9 <property name="sname" length="20"></property>
10 <property name="description" length="100"></property>
11 <!--
12 table就是用来描述第三张表
13 key 用来描述外键，多对多的关系看对哪张表建立映射
14 此表是描述Student信息的，所以 key中 column写sid
15
16 many-to-many 中用于建立关系的所以 在第三张表中关系用cid建立
17 -->
18 <set name="courses" table="student_course">
19 <key>
20 <column name="sid"></column>
21 </key>
22 <many-to-many class="cn.itcast.hiberate.sh.domain.Course" column="cid">
23 </many-to-many >
24 </set>
25 </class>
26 </hibernate-mapping>
Course.java
1 package cn.itcast.hiberate.sh.domain;
2
3 import java.io.Serializable;
4 import java.util.Set;
5
6 public class Course implements Serializable {
7 private Long cid;
8 private String cname;
9 private String description;
10 private Set<Student> students;
11 public Long getCid() {
12 return cid;
13 }
14 public void setCid(Long cid) {
15 this.cid = cid;
16 }
17 public String getCname() {
18 return cname;
19 }
20 public void setCname(String cname) {
21 this.cname = cname;
22 }
23 public String getDescription() {
24 return description;
25 }
26 public void setDescription(String description) {
27 this.description = description;
28 }
29 public Set<Student> getStudents() {
30 return students;
31 }
32 public void setStudents(Set<Student> students) {
33 this.students = students;
34 }
35
36 }
Course.xml
1 <?xml version="1.0" encoding="utf-8"?>
2 <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
3 "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
4 <hibernate-mapping>
5 <class name="cn.itcast.hiberate.sh.domain.Course">
6 <id name="cid" length="5" type="java.lang.Long">
7 <generator class="increment"></generator>
8 </id>
9 <property name="cname" length="20" type="java.lang.String"></property>
10
11 <property name="description" length="100" type="java.lang.String"></property>
12 <!--
13 set元素对应类中的set集合
14 通过set元素使classes表与student表建立关联
15 key是通过外键的形式让两张表建立关联，针对的是哪张表看哪个
16 one-to-many是通过类的形式让两个类建立关联
17
18 cascade 级联
19 save-update
20 1、当 保存班级的时候，对学生进行怎么样的操作
21 如果学生对象在数据库中没有对应的值，这个时候会执行save操作
22 如果学生对象在数据库中有对应的值，这个时候会执行update操作
23 delete
24 all
25 inverse 维护关系
26 true 不维护关系
27 false 维护关系
28 default false
29 -->
30 <set name="students" table="student_course">
31 <!--
32 key是用来描述外键 哪张表就哪個外鍵
33 <many-to-many> 中的cid 描述类与类之间的关系
34 -->
35 <key>
36 <column name="cid"></column>
37 </key>
38 <many-to-many class="cn.itcast.hiberate.sh.domain.Student" column="sid">
39 </many-to-many>
40 </set>
41 </class>
42 </hibernate-mapping>
hibernate.cfg.xml
1 <?xml version=‘1.0‘ encoding=‘utf-8‘?>
2 <!DOCTYPE hibernate-configuration PUBLIC
3 "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
4 "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
5 <hibernate-configuration>
6 <!--
7 一个session-factory只能连接一个数据库
8 -->
9 <session-factory>
10 <!--
11 数据库的用户名
12 -->
13 <property name="connection.username">root</property>
14 <!--
15 密码
16 -->
17 <property name="connection.password">friends</property>
18 <!--
19 url
20 -->
21 <property name="connection.url">
22 jdbc:mysql://localhost:3306/itcast_sh_hibernate_manyTomany
23 </property>
24 <!--
25 作用：根据持久化类和映射文件生成表
26 validate
27 create-drop
28 create
29 update
30 -->
31 <property name="hbm2ddl.auto">update</property>
32 <!--
33 显示hibernate内部生成的sql语句
34 -->
35
36 <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
37 <property name="show_sql">true</property>
38 <mapping resource="cn/itcast/hiberate/sh/domain/Course.hbm.xml" />
39 <mapping resource="cn/itcast/hiberate/sh/domain/Student.hbm.xml" />
40
41 </session-factory>
42 </hibernate-configuration>
test.java
1 package cn.itcast.hiberate.sh.test;
2
3 import org.hibernate.Session;
4 import org.hibernate.SessionFactory;
5 import org.hibernate.Transaction;
6 import org.hibernate.cfg.Configuration;
7 import org.junit.Test;
8
9 import cn.itcast.hibernate.sh.utils.HiberanteUtils;
10
11 public class CreateTable extends HiberanteUtils{
12
13 @Test
14 public void createTable()
15 {
16 Configuration config=new Configuration();
17 config.configure();
18 // SessionFactory sessionFactory=config.buildSessionFactory();
19 // Session session=sessionFactory.openSession();
20 // Transaction transaction=session.beginTransaction();
21 //
22 //
23 // transaction.commit();
24 // session.close();
25 }
26 }
hibernate建表多对多建表
时间： 2025-01-02 06:47:58