Role.java
package com.many2many.bean;
import java.util.Set;
public class Role {
private int id;
private String name;
private Set < User > users;
public int getId() {
return id;
}
public void setId( int id) {
this .id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this .name = name;
}
public Set < User > getUsers() {
return users;
}
public void setUsers(Set < User > users) {
this .users = users;
}
}
User.java
package com.many2many.bean;
import java.util.Set;
public class User {
private int id;
private String name;
private Set < Role > roles;
public int getId() {
return id;
}
public void setId( int id) {
this .id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this .name = name;
}
public Set < Role > getRoles() {
return roles;
}
public void setRoles(Set < Role > roles) {
this .roles = roles;
}
}
映射文件
Role.hbm.xml
<? 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 package ="com.many2many.bean" >
< class name ="Role" table ="roles" catalog ="Hibernate_Many2Many" >
< id name ="id" column ="id" >
< generator class ="native" />
</ id >
< property name ="name" column ="name" />
< set name ="users" table ="user_role" cascade ="all" >
< key >
< column name ="role_id" />
</ key >
< many-to-many column ="user_id" class ="User" />
</ set >
</ class >
</ hibernate-mapping >
User.hbm.xml
<? 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 package ="com.many2many.bean" >
< class name ="User" table ="users" catalog ="Hibernate_Many2Many" >
< id name ="id" column ="id" >
< generator class ="native" />
</ id >
< property name ="name" column ="name" />
< set name ="roles" table ="user_role" cascade ="all" >
< key >
< column name ="user_id" />
</ key >
< many-to-many column ="role_id" class ="Role" />
</ set >
</ class >
</ hibernate-mapping >
导出的sql
create table Hibernate_Many2Many.roles (
id integer not null auto_increment,
name varchar ( 255 ),
primary key (id)
)
create table Hibernate_Many2Many.users (
id integer not null auto_increment,
name varchar ( 255 ),
primary key (id)
)
create table user_role (
role_id integer not null ,
user_id integer not null ,
primary key ( user_id , role_id)
)
alter table user_role
add index FK143BF46ADA6B394F (role_id),
add constraint FK143BF46ADA6B394F
foreign key (role_id)
references Hibernate_Many2Many.roles (id)
alter table user_role
add index FK143BF46A7F95FD2F ( user_id ),
add constraint FK143BF46A7F95FD2F
foreign key ( user_id )
references Hibernate_Many2Many.users (id)
测试代码
@Test
public void insert(){
Session session = HibernateSessionFactory.getSession();
Transaction transaction = session.beginTransaction();
try {
transaction.begin();
User user = new User();
user.setName( " 张三 " );
Role role = new Role();
role.setName( " 管理员 " );
Set < Role > roles = new HashSet < Role > ();
roles.add(role);
user.setRoles(roles);
session.persist(user);
transaction.commit();
} catch (HibernateException e) {
e.printStackTrace();
transaction.rollback();
}
}
@Test
public void select(){
Session session = HibernateSessionFactory.getSession();
User user = (User) session.get(User. class , 1 );
System.out.println(user.getName());
Set < Role > roles = user.getRoles();
for (Iterator < Role > iterator = roles.iterator(); iterator.hasNext();) {
Role role = (Role) iterator.next();
System.out.println(role.getName());
}
}
