HibernateManytoMany
public class HibernateManytoMany { //演示维护第三张表 @Test public void testTable2() { SessionFactory sessionFactory = null; Session session = null; Transaction tx = null; try { //得到sessionFactory sessionFactory = HibernateUtils.getSessionFactory(); //得到session session = sessionFactory.openSession(); //开启事务 tx = session.beginTransaction(); // 让某个用户没有有某个角色 User user = session.get(User.class, 2); Role role = session.get(Role.class, 3); //2 从用户里面把角色去掉 user.getSetRole().remove(role); //提交事务 tx.commit(); } catch (Exception e) { tx.rollback(); } finally { session.close(); //sessionFactory不需要关闭 sessionFactory.close(); } } //演示维护第三张表 @Test public void testTable1() { SessionFactory sessionFactory = null; Session session = null; Transaction tx = null; try { //得到sessionFactory sessionFactory = HibernateUtils.getSessionFactory(); //得到session session = sessionFactory.openSession(); //开启事务 tx = session.beginTransaction(); // 让某个用户有某个角色 //让lucy有经纪人角色 //1 查询lucy和经纪人 User lucy = session.get(User.class, 2); Role role = session.get(Role.class, 5); //2 把角色放到用户的set集合里面 lucy.getSetRole().add(role); //提交事务 tx.commit(); } catch (Exception e) { tx.rollback(); } finally { session.close(); //sessionFactory不需要关闭 sessionFactory.close(); } } //演示多对多修级联保存 @Test public void testDelete() { SessionFactory sessionFactory = null; Session session = null; Transaction tx = null; try { //得到sessionFactory sessionFactory = HibernateUtils.getSessionFactory(); //得到session session = sessionFactory.openSession(); //开启事务 tx = session.beginTransaction(); User user = session.get(User.class, 4); session.delete(user); //提交事务 tx.commit(); } catch (Exception e) { tx.rollback(); } finally { session.close(); //sessionFactory不需要关闭 sessionFactory.close(); } } //演示多对多修级联保存 @Test public void testSave() { SessionFactory sessionFactory = null; Session session = null; Transaction tx = null; try { //得到sessionFactory sessionFactory = HibernateUtils.getSessionFactory(); //得到session session = sessionFactory.openSession(); //开启事务 tx = session.beginTransaction(); //添加两个用户,为每个用户添加两个角色 //1 创建对象 User user1 = new User(); user1.setUser_name("lucy"); user1.setUser_password("123"); User user2 = new User(); user2.setUser_name("mary"); user2.setUser_password("456"); Role r1 = new Role(); r1.setRole_name("总经理"); r1.setRole_memo("总经理"); Role r2 = new Role(); r2.setRole_name("秘书"); r2.setRole_memo("秘书"); Role r3 = new Role(); r3.setRole_name("保安"); r3.setRole_memo("保安"); //2 建立关系,把角色放到用户里面 // user1 -- r1/r2 user1.getSetRole().add(r1); user1.getSetRole().add(r2); // user2 -- r2/r3 user2.getSetRole().add(r2); user2.getSetRole().add(r3); //3 保存用户 session.save(user1); session.save(user2); //提交事务 tx.commit(); } catch (Exception e) { tx.rollback(); } finally { session.close(); //sessionFactory不需要关闭 sessionFactory.close(); } } }
User
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
public class User { private Integer user_id;//用户id private String user_name;//用户名称 private String user_password;//用户密码 public Set<Role> getSetRole() { return setRole; } public void setSetRole(Set<Role> setRole) { this.setRole = setRole; } private Set<Role> setRole = new HashSet<>(); public Integer getUser_id() { return user_id; } public void setUser_id(Integer user_id) { this.user_id = user_id; } public String getUser_name() { return user_name; } public void setUser_name(String user_name) { this.user_name = user_name; } public String getUser_password() { return user_password; } public void setUser_password(String user_password) { this.user_password = user_password; } }
User.xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> <hibernate-mapping> <class name="k.manytomany.User" table="t_user"> <id name="user_id" column="user_id"> <generator class="native"></generator> </id> <property name="user_name" column="user_name"></property> <property name="user_password" column="user_password"></property> <set name="setRole" table="user_role" cascade="save-update,delete"> <key column="userid"></key> <many-to-many class="k.manytomany.Role" column="roleid"></many-to-many> </set> </class> </hibernate-mapping>
Role
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
public class Role { private Integer role_id;//角色id private String role_name;//角色名称 private String role_memo;//角色描述 private Set<User> setUser = new HashSet<>(); public Set<User> getSetUser() { return setUser; } public void setSetUser(Set<User> setUser) { this.setUser = setUser; } public Integer getRole_id() { return role_id; } public void setRole_id(Integer role_id) { this.role_id = role_id; } public String getRole_name() { return role_name; } public void setRole_name(String role_name) { this.role_name = role_name; } public String getRole_memo() { return role_memo; } public void setRole_memo(String role_memo) { this.role_memo = role_memo; } }
Role.xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> <hibernate-mapping> <class name="k.manytomany.Role" table="t_role"> <id name="role_id" column="role_id"> <generator class="native"></generator> </id> <property name="role_name" column="role_name"></property> <property name="role_memo" column="role_memo"></property> <set name="setUser" table="user_role" > <key column="roleid"></key> <many-to-many class="k.manytomany.User" column="userid"></many-to-many> </set> </class> </hibernate-mapping>
HibernateUtils
public class HibernateUtils { static Configuration cfg = null; static SessionFactory sessionFactory = null; //静态代码块实现 static { //加载核心配置文件 cfg = new Configuration(); cfg.configure(); sessionFactory = cfg.buildSessionFactory(); } //提供返回与本地线程帮的session的方法 public static Session getSessionobject() { return sessionFactory.getCurrentSession(); } //提供方法返回sessionFactory public static SessionFactory getSessionFactory() { return sessionFactory; } public static void main(String[] args) { } }
hibernate.cfg.xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <!-- 第一部分: 配置数据库信息 必须的 --> <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> <property name="hibernate.connection.url">jdbc:mysql:///hibernate_day01</property> <property name="hibernate.connection.useUnicode">true</property> <property name="hibernate.connection.characterEncoding">UTF-8</property> <property name="hibernate.connection.username">root</property> <property name="hibernate.connection.password">root3306</property> <!-- 第二部分: 配置hibernate信息 可选的--> <!-- 输出底层sql语句 --> <property name="hibernate.show_sql">true</property> <!-- 输出底层sql语句格式 --> <property name="hibernate.format_sql">true</property> <!-- hibernate帮创建表,需要配置之后 update: 如果已经有表,更新,如果没有,创建 --> <property name="hibernate.hbm2ddl.auto">update</property> <!-- 配置数据库方言 在mysql里面实现分页 关键字 limit,只能使用mysql里面 在oracle数据库,实现分页rownum 让hibernate框架识别不同数据库的自己特有的语句 --> <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property> <!-- 第三部分: 把映射文件放到核心配置文件中 必须的--> <!--<mapping resource="k/entity/User.hbm.xml"/>--> <mapping resource="k/manytomany/User.xml"/> <mapping resource="k/manytomany/Role.xml"/> </session-factory> </hibernate-configuration>