hibernate中many-to-many基本操作

创建数据库

create database student;

use student;

create table studentInfo(

stuNo integer auto_increment not null primary key,

stuName varchar(50) not null

);

create table courseInfo(

courseNo integer auto_increment not null primary key,

courseName varchar(30) not null

);

create table student_course(

stuNo int,

courseNo int,

foreign key(stuNo) references studentInfo(stuNo),

foreign key(courseNo) references courseInfo(courseNo)

);

show databases;



Pojo

package com.etp.zsh.pojo;

import java.util.HashSet;

import java.util.Set;

public class Courseinfo implements java.io.Serializable {

private Integer courseNo;

private String courseName;

private Set studentinfos = new HashSet(0);



public Courseinfo() {

}



public Courseinfo(String courseName) {

this.courseName = courseName;

}



public Courseinfo(String courseName, Set studentinfos) {

this.courseName = courseName;

this.studentinfos = studentinfos;

}

// Property accessors

public Integer getCourseNo() {

return this.courseNo;

}

public void setCourseNo(Integer courseNo) {

this.courseNo = courseNo;

}

public String getCourseName() {

return this.courseName;

}

public void setCourseName(String courseName) {

this.courseName = courseName;

}

public Set getStudentinfos() {

return this.studentinfos;

}

public void setStudentinfos(Set studentinfos) {

this.studentinfos = studentinfos;

}

}

<?xml version="1.0" encoding="utf-8"?>

<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"

"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>

<class name="com.etp.zsh.pojo.Courseinfo" table="courseinfo" catalog="student">

<id name="courseNo" type="java.lang.Integer">

<column name="courseNo" />

<generator class="native" />

</id>

<property name="courseName" type="java.lang.String">

<column name="courseName" length="30" not-null="true" />

</property>

<set name="studentinfos" table="student_course" catalog="student">

<key>

<column name="courseNo" />

</key>

<many-to-many entity-name="com.etp.zsh.pojo.Studentinfo">

<column name="stuNo" />

</many-to-many>

</set>

</class>

</hibernate-mapping>





package com.etp.zsh.pojo;

import java.util.HashSet;

import java.util.Set;

public class Studentinfo implements java.io.Serializable {

// Fields

private Integer stuNo;

private String stuName;

private Set courseinfos = new HashSet(0);

// Constructors



public Studentinfo() {

}



public Studentinfo(String stuName) {

this.stuName = stuName;

}



public Studentinfo(String stuName, Set courseinfos) {

this.stuName = stuName;

this.courseinfos = courseinfos;

}

// Property accessors

public Integer getStuNo() {

return this.stuNo;

}

public void setStuNo(Integer stuNo) {

this.stuNo = stuNo;

}

public String getStuName() {

return this.stuName;

}

public void setStuName(String stuName) {

this.stuName = stuName;

}

public Set getCourseinfos() {

return this.courseinfos;

}

public void setCourseinfos(Set courseinfos) {

this.courseinfos = courseinfos;

}

}



<?xml version="1.0" encoding="utf-8"?>

<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"

"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>

<class name="com.etp.zsh.pojo.Studentinfo" table="studentinfo"

catalog="student">

<id name="stuNo" type="java.lang.Integer">

<column name="stuNo" />

<generator class="native" />

</id>

<property name="stuName" type="java.lang.String">

<column name="stuName" length="50" not-null="true" />

</property>

<set name="courseinfos" table="student_course" catalog="student">

<key>

<column name="stuNo" />

</key>

<many-to-many entity-name="com.etp.zsh.pojo.Courseinfo">

<column name="courseNo" />

</many-to-many>

</set>

</class>

</hibernate-mapping>



HibernateSessionFactory

package com.etp.zsh.pojo;

import org.hibernate.HibernateException;

import org.hibernate.Session;

import org.hibernate.cfg.Configuration;

public class HibernateSessionFactory

{



private static String CONFIG_FILE_LOCATION = "/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;

}

}



hibernate.cfg.xml

<?xml version='1.0' encoding='UTF-8'?>

<!DOCTYPE hibernate-configuration PUBLIC

"-//Hibernate/Hibernate Configuration DTD 3.0//EN"

"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<!-- Generated by MyEclipse Hibernate Tools. -->

<hibernate-configuration>

<session-factory>

<property name="show_sql">true</property>

<property name="myeclipse.connection.profile">

com.mysql.jdbc.Driver

</property>

<property name="connection.url">

jdbc:mysql://localhost:3306/student

</property>

<property name="connection.username">root</property>

<property name="connection.password">root</property>

<property name="connection.driver_class">

com.mysql.jdbc.Driver

</property>

<property name="dialect">

org.hibernate.dialect.MySQLDialect

</property>

<mapping resource="com/etp/zsh/pojo/Studentinfo.hbm.xml" />

<mapping resource="com/etp/zsh/pojo/Courseinfo.hbm.xml" />

</session-factory>

</hibernate-configuration>



测试类

package com.etp.zsh.pojo;

import org.hibernate.Session;

import org.hibernate.Transaction;

public class Test

{

// 实体表中插入数据

public void testManyToMany_1()

{

Studentinfo s1 = new Studentinfo("张三");

Studentinfo s2 = new Studentinfo("李四");

Studentinfo s3 = new Studentinfo("王五");

Courseinfo c1 = new Courseinfo("物理");

Courseinfo c2 = new Courseinfo("数学");

Courseinfo c3 = new Courseinfo("化学");

Session session = null;

Transaction tran = null;

try

{

session = HibernateSessionFactory.getSession();

tran = session.beginTransaction();

session.save(c1);

session.save(c2);

session.save(c3);

session.save(s1);

session.save(s2);

session.save(s3);

tran.commit();

}

catch (Exception e)

{

// TODO: handle exception

e.printStackTrace();

tran.rollback();

}

finally

{

HibernateSessionFactory.closeSession();

}

}

// 从Student端维护关系表

public void testManyToManay_2()

{

Session session = null;

Transaction tran = null;

try

{

session = HibernateSessionFactory.getSession();

tran = session.beginTransaction();

Studentinfo st = (Studentinfo) session.get(Studentinfo.class, 1);

Courseinfo cs = (Courseinfo) session.get(Courseinfo.class, 2);

st.getCourseinfos().add(cs);

tran.commit();

}

catch (Exception e)

{

e.printStackTrace();

tran.rollback();

}

finally

{

HibernateSessionFactory.closeSession();

}

}

// 从课程端维护

public void testManyToMany_3()

{

Session session = null;

Transaction tran = null;

try

{

session = HibernateSessionFactory.getSession();

tran = session.beginTransaction();

Studentinfo st = (Studentinfo) session.get(Studentinfo.class, 2);

Courseinfo cs = (Courseinfo) session.get(Courseinfo.class, 1);

cs.getStudentinfos().add(st);

tran.commit();

}

catch (Exception e)

{

// TODO: handle exception

e.printStackTrace();

tran.rollback();

}

finally

{

HibernateSessionFactory.closeSession();

}

}

// 从关系表中删除数据

// 而实体表中不会有变化

public void DeleteFromRelationTable()

{

Session session = null;

Transaction tran = null;

try

{

session = HibernateSessionFactory.getSession();

tran = session.beginTransaction();

// 删除学号为1，课程号为2的关系表中的记录(从学生端维护)

Studentinfo stu = (Studentinfo) session.createQuery

("from Studentinfo s where s.stuNo = 1").uniqueResult();

Courseinfo cs = (Courseinfo) session.get(Courseinfo.class, 2);

stu.getCourseinfos().remove(cs);



// 删除学号为1的同学关联表中所有相关记录

Studentinfo s = (Studentinfo) session.createQuery

("from Studentinfo s where s.stuNo = 1").uniqueResult();

s.getCourseinfos().clear();



// 删除课程为2的课程关联表中所有相关记录

Courseinfo c = (Courseinfo) session.get(Courseinfo.class, 2);

c.getStudentinfos().clear();



tran.commit();

}

catch (Exception e)

{

e.printStackTrace();

tran.rollback();

}

finally

{

HibernateSessionFactory.closeSession();

}

}

public static void main(String[] args)

{

Test t = new Test();

// t.testManyToMany_1();

// t.testManyToMany_2();

t.DeleteFromRelationTable();

}

}