Hibernate多对多关联

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Hibernate 多对多关联一、多对多关联多对多关联时，要实现向中间表插入数据.

操作步骤：

1. 代码建立两表之间关系如(1)

2. 对一个表对象做增加操作注意:这个表对象必须是添加对象如 (2)

{

Role role1 = new Role();

role1.setName("spring");

Role role2 = new Role();

role2.setName("java");

Function function1 = new Function();

function1.setFunctionCode("addrolefunction.jspa");

securityService.addFunction(function1);

(1)role1.getFunctions().add(function1);

(1)role2.getFunctions().add(function1);

(2) securityService.addRole(role1);

(2) securityService.addRole(role2);}

2．删除一条记录

Function function1 =securityService.getFunctionById("9");

Role role1 = securityService.getRoleById("6");

role1.getFunctions().remove(function1);

securityService.deleteFunctionByID("9");

例子：

SQL(MY SQL):create table tgroup ( group_id int not nullauto_increment, name varchar(16) not null default '', primary key(group_id)) type=innodb;

create table trole ( role_id int not null auto_increment, namevarchar(16) not null default '', primary key (role_id))type=innodb;

create table tgroup_role ( group_id int not null, role_id intnot null, primary key(group_id, role_id), index (group_id), foreignkey (group_id) references tgroup(group_id), index (role_id),foreign key (role_id) references trole(role_id)) type=innodb;

Group 类：

package ivan.hibernate.many2many;

public class Group {

private int id;

private String name;

private Set roles = new HashSet(); ...

}

Group.hbm.xml：

Role 类：

package ivan.hibernate.many2many;

public class Role {

private int id;

private String name;

private Set groups = new HashSet();...

}

Role.hbm.xml：

hibernate.cfg.xml 同前面的例子差不多。

public class Test {

public static void main(String[] args)throws HibernateException {

Role role1 = new Role();

role1.setName("Role1");

Role role2 = new Role();

role2.setName("Role2");

Role role3 = new Role();

role3.setName("Role3");

Group group1 = new Group();

group1.setName("group1");

Group group2 = new Group();

group2.setName("group2");

Group group3 = new Group();

group3.setName("group3");

group1.getRoles().add(role1);

group1.getRoles().add(role2);

group2.getRoles().add(role2);

group2.getRoles().add(role3);

group3.getRoles().add(role1);

group3.getRoles().add(role3);

role1.getGroups().add(group1);

role1.getGroups().add(group3);

role2.getGroups().add(group1);

role2.getGroups().add(group2);

role3.getGroups().add(group2);

role3.getGroups().add(group3);

SessionFactory sessionFactory = newConfiguration().configure().buildSessionFactory();

Session session =sessionFactory.openSession();

Transaction tx=session.beginTransaction();

session.save(role1);

session.save(role2);

session.save(role3);

session.save(group1);

session.save(group2);

session.save(group3);

tx.commit();

session.close();

sessionFactory.close();

}

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