一個例子 實現多對多的 插入 采用中間表的形式 進行操作
代碼如下：
teacher table
create table `test`.`teacher`(
`tid` int not null auto_increment,
`tname` varchar(40),
primary key (`tid`)
);
create unique index `PRIMARY` on `test`.`teacher`(`tid`);
studnt table
create table `test`.`student`(
`sid` int not null auto_increment,
`sname` varchar(40),
primary key (`sid`)
);
create unique index `PRIMARY` on `test`.`student`(`sid`);
stu_tea_tab table
create table `test`.`stu_tea_tab`(
`tid` int,
`sid` int
);
===========================
teacher.class
package com.test.beans;
import java.util.HashSet;
import java.util.Set;
public class Teacher
{
private Integer tid;
private String tname;
private Set students = new HashSet ( );
public Integer getTid()
{
return tid;
}
public void setTid(Integer tid)
{
this.tid = tid;
}
public String getTname()
{
return tname;
}
public void setTname(String tname)
{
this.tname = tname;
}
public Set getStudents()
{
return students;
}
public void setStudents(Set students)
{
this.students = students;
}
}
teacher 的配置文件：
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"
<!--
Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
<class name="com.test.beans.Teacher" table="teacher">
<id name="tid" type="java.lang.Integer">
<column name="tid"></column>
<generator class="native"></generator>
</id>
<property name="tname" type="java.lang.String">
<column name="tname" length="40"></column>
</property>
<set name="students" table="stu_tea_tab" inverse="true" cascade="save-update">
<key column="tid"></key>
<many-to-many class="com.test.beans.Student" column="sid"></many-to-many>
</set>
</class>
</hibernate-mapping>
student.class
package com.test.beans;
import java.util.HashSet;
import java.util.Set;
public class Student
{
private Integer sid;
private String sname;
private Set teachers = new HashSet();
public String getSname()
{
return sname;
}
public void setSname(String sname)
{
this.sname = sname;
}
public Integer getSid()
{
return sid;
}
public void setSid(Integer sid)
{
this.sid = sid;
}
public Set getTeachers()
{
return teachers;
}
public void setTeachers(Set teachers)
{
this.teachers = teachers;
}
}
student.hbm.xml
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"
<!--
Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
<class name="com.test.beans.Student" table="student" >
<id name="sid" type="java.lang.Integer">
<column name="sid"></column>
<generator class="native"></generator>
</id>
<property name="sname" type="java.lang.String">
<column name="sname" length="40"></column>
</property>
<set name="teachers"
table="stu_tea_tab"
cascade="save-update"
inverse="false"
>
<key column="sid"></key>
<many-to-many class="com.test.beans.Teacher" column="tid"></many-to-many>
</set>
</class>
</hibernate-mapping>
hibernatesessionfactory.java
package com.test.hibernate;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.cfg.Configuration;
public class HibernateSessionFactory {
private static String CONFIG_FILE_LOCATION = "/com/test/hibernate/hibernate.cfg.xml";
private static final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();
private static Configuration configuration = new Configuration();
private static org.hibernate.SessionFactory sessionFactory;
private static String configFile = CONFIG_FILE_LOCATION;
static {
try {
configuration.configure(configFile);
sessionFactory = configuration.buildSessionFactory();
} catch (Exception e) {
System.err
.println("%%%% Error Creating SessionFactory %%%%");
e.printStackTrace();
}
}
private HibernateSessionFactory() {
}
public static Session getSession() throws HibernateException {
Session session = (Session) threadLocal.get();
if (session == null || !session.isOpen()) {
if (sessionFactory == null) {
rebuildSessionFactory();
}
session = (sessionFactory != null) ? sessionFactory.openSession()
: null;
threadLocal.set(session);
}
return session;
}
public static void rebuildSessionFactory() {
try {
configuration.configure(configFile);
sessionFactory = configuration.buildSessionFactory();
} catch (Exception e) {
System.err
.println("%%%% Error Creating SessionFactory %%%%");
e.printStackTrace();
}
}
public static void closeSession() throws HibernateException {
Session session = (Session) threadLocal.get();
threadLocal.set(null);
if (session != null) {
session.close();
}
}
public static org.hibernate.SessionFactory getSessionFactory() {
return sessionFactory;
}
public static void setConfigFile(String configFile) {
HibernateSessionFactory.configFile = configFile;
sessionFactory = null;
}
public static Configuration getConfiguration() {
return configuration;
}
}
studentdao.java
package com.test.daos;
import org.hibernate.Session;
import org.hibernate.Transaction;
import com.test.beans.Student;
import com.test.hibernate.HibernateSessionFactory;
public class StudentDao
{
public void addStudent(Student student)
{
Session session = HibernateSessionFactory.getSession ( );
Transaction tr = session.beginTransaction ( );
session.save ( student );
tr.commit();
HibernateSessionFactory.closeSession ( );
}
}
測試類：
package com.test.test;
import com.test.beans.Student;
import com.test.beans.Teacher;
import com.test.daos.StudentDao;
import com.test.daos.TeacherDao;
public class Test
{
public static void main(String args[])
{
Student stu1 = new Student();
stu1.setSname ( "stu1" );
Student stu2 = new Student();
stu2.setSname ( "stu2" );
Teacher tea1 = new Teacher();
tea1.setTname ( "tea1" );
Teacher tea2 = new Teacher();
tea2.setTname ( "tea2" );
stu1.getTeachers ( ).add ( tea1 );
stu1.getTeachers ( ).add ( tea2 );
stu2.getTeachers ( ).add ( tea1 );
stu2.getTeachers ( ).add ( tea2 );
StudentDao studentDao = new StudentDao();
studentDao.addStudent ( stu1 );
studentDao.addStudent ( stu2 );
}
}
說明：在這里我們采用 學生 握有主動權去選擇老師。