hibernate框架学习笔记9：多对多关系案例

package domain;
//用户实体
import java.util.HashSet;
import java.util.Set;

public class User {
    private Long user_id;
    private String user_code;
    private String user_name;
    private String user_password;
    private Character user_state;
    //表达多对多
    private Set<Role> roles = new HashSet<Role>();
    public Long getUser_id() {
        return user_id;
    }
    public void setUser_id(Long user_id) {
        this.user_id = user_id;
    }
    public String getUser_code() {
        return user_code;
    }
    public void setUser_code(String user_code) {
        this.user_code = user_code;
    }
    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;
    }
    public Character getUser_state() {
        return user_state;
    }
    public void setUser_state(Character user_state) {
        this.user_state = user_state;
    }
    public Set<Role> getRoles() {
        return roles;
    }
    public void setRoles(Set<Role> roles) {
        this.roles = roles;
    }
    
    
    
}

package domain;
//角色实体
import java.util.HashSet;
import java.util.Set;

public class Role {
    private Long role_id;
    private String role_name;
    private String role_memo;
    //表达多对多
    private Set<User> users = new HashSet<User>();
    public Long getRole_id() {
        return role_id;
    }
    public void setRole_id(Long 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;
    }
    public Set<User> getUsers() {
        return users;
    }
    public void setUsers(Set<User> users) {
        this.users = users;
    }
    
}

<?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 package="domain" >
    <class name="Role" table="sys_role" >
        <id name="role_id"  >
            <generator class="native"></generator>
        </id>
        <property name="role_name"  ></property>
        <property name="role_memo"  ></property>
        <set name="users" table="sys_user_role">
            <key column="role_id" ></key>
            <many-to-many class="User" column="user_id" ></many-to-many>
        </set>
    </class>
</hibernate-mapping>

<?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>
        <!-- 数据库驱动 -->
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <!-- 数据库url -->
        <property name="hibernate.connection.url">jdbc:mysql:///hibernate</property>
        <!-- 数据库连接用户名 -->
        <property name="hibernate.connection.username">root</property>
        <!-- 数据库连接密码 -->
        <property name="hibernate.connection.password">xuyiqing</property>
        
        <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
        <!-- 将hibernate生成的sql语句打印到控制台 -->
        <property name="hibernate.show_sql">true</property>
        <!-- 将hibernate生成的sql语句格式化(语法缩进) -->
        <property name="hibernate.format_sql">true</property>
        
        <property name="hibernate.hbm2ddl.auto">update</property>
        <!-- 引入orm元数据 路径书写: 填写src下的路径 -->
        
        <property name="hibernate.connection.isolation">4</property>
         
        <!-- 指定session与当前线程绑定 -->
        <property name="hibernate.current_session_context_class">thread</property>
        <mapping resource="domain/User.hbm.xml" />
        <mapping resource="domain/Role.hbm.xml" />

    </session-factory>
</hibernate-configuration>

package utils;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class HibernateUtils {
    private static SessionFactory sf;
    
    static{
        //1 创建,调用空参构造
        Configuration conf = new Configuration().configure();
        //2 根据配置信息,创建 SessionFactory对象
         sf = conf.buildSessionFactory();
    }
    
    //获得session => 获得全新session
    public static Session openSession(){
                //3 获得session
                Session session = sf.openSession();
                
                return session;
        
    }
    //获得session => 获得与线程绑定的session
    public static Session getCurrentSession(){
        //3 获得session
        Session session = sf.getCurrentSession();
        
        return session;
    }    
}