Hibernate（三）：多对多（many-to-many）

以下是多对多的基础配置

-- 多对多

-- 用户
CREATE TABLE users(
uid int PRIMARY KEY auto_increment, --  用户id
uname VARCHAR(50) not null        -- 用户名
);

-- 角色
CREATE TABLE roles(
rid int PRIMARY KEY auto_increment, -- 角色id
rname VARCHAR(50) not null  -- 角色名
);

-- 用户角色关系表
CREATE TABLE relation(
uid int not null,  --  用户id
rid int not null     -- 角色id
);

Roles.hbm.xml

<hibernate-mapping>
    <class name="club.lygangdai.pojo.Roles" table="roles">
        <id name="rid" type="int">
            <column name="rid" />
            <generator class="native" />
        </id>
        <property name="rname" type="java.lang.String">
            <column name="rname" />
        </property>
		<set name="users" table="relation" >
			<key column="rid"></key>
			<many-to-many class="club.lygangdai.pojo.Users" column="uid" />
		</set>
    </class>
</hibernate-mapping>

Roles.java

package club.lygangdai.pojo;

import java.util.HashSet;
import java.util.Set;

/** 
 * @ClassName: Roles 
 * @Description: TODO(角色表) 
 * @author Uncle
 * @date 2018年8月9日 下午7:11:39 
 *  
 */
public class Roles {
	private int rid;
	private String rname;
	private Set<Users> users = new HashSet<Users>();
	/** 
	 * @Description: TODO(这里用一句话描述这个类的作用) 
	 * @param rid
	 * @param rname 
	 */
	public Roles(int rid, String rname) {
		super();
		this.rid = rid;
		this.rname = rname;
	}
	/** 
	 * @Description: TODO(这里用一句话描述这个类的作用)  
	 */
	public Roles() {
		super();
	}
	/** 
	 * @return rid 
	 */
	public int getRid() {
		return rid;
	}
	/** 
	 * @param rid 要设置的 rid 
	 */
	public void setRid(int rid) {
		this.rid = rid;
	}
	/** 
	 * @return rname 
	 */
	public String getRname() {
		return rname;
	}
	/** 
	 * @param rname 要设置的 rname 
	 */
	public void setRname(String rname) {
		this.rname = rname;
	}
	/** 
	 * @return users 
	 */
	public Set<Users> getUsers() {
		return users;
	}
	/** 
	 * @param users 要设置的 users 
	 */
	public void setUsers(Set<Users> users) {
		this.users = users;
	}
	/* (非 Javadoc) 
	 * @Title: toString
	 * @Description: TODO(这里用一句话描述这个方法的作用) 
	 * @return 
	 * @see java.lang.Object#toString() 
	 */
	@Override
	public String toString() {
		return "Roles [rid=" + rid + ", rname=" + rname + "]";
	}
	
	
}

Users.hbm.xml

<hibernate-mapping>
    <class name="club.lygangdai.pojo.Users" table="users">
        <id name="uid" type="int">
            <column name="uid" />
            <generator class="native" />
        </id>
        <property name="uname" type="java.lang.String">
            <column name="uname" />
        </property>
        <set name="roles" table="relation" cascade="all-delete-orphan" inverse="true" >
            <key>
                <column name="uid" />
            </key>
            <many-to-many class="club.lygangdai.pojo.Roles" column="rid"/>
        </set>
    </class>
</hibernate-mapping>

Users.java

package club.lygangdai.pojo;

import java.util.HashSet;
import java.util.Set;

/** 
 * @ClassName: Users 
 * @Description: TODO(用户表) 
 * @author Uncle
 * @date 2018年8月9日 下午7:10:23 
 *  
 */
public class Users {
	private int uid;
	private String uname;
	private Set<Roles> roles = new HashSet<Roles>();
	/** 
	 * @Description: TODO(这里用一句话描述这个类的作用) 
	 * @param uid
	 * @param uname 
	 */
	public Users(int uid, String uname) {
		super();
		this.uid = uid;
		this.uname = uname;
	}
	/** 
	 * @Description: TODO(这里用一句话描述这个类的作用)  
	 */
	public Users() {
		super();
	}
	/** 
	 * @return uid 
	 */
	public int getUid() {
		return uid;
	}
	/** 
	 * @param uid 要设置的 uid 
	 */
	public void setUid(int uid) {
		this.uid = uid;
	}
	/** 
	 * @return uname 
	 */
	public String getUname() {
		return uname;
	}
	/** 
	 * @param uname 要设置的 uname 
	 */
	public void setUname(String uname) {
		this.uname = uname;
	}
	/** 
	 * @return roles 
	 */
	public Set<Roles> getRoles() {
		return roles;
	}
	/** 
	 * @param roles 要设置的 roles 
	 */
	public void setRoles(Set<Roles> roles) {
		this.roles = roles;
	}
	/* (非 Javadoc) 
	 * @Title: toString
	 * @Description: TODO(这里用一句话描述这个方法的作用) 
	 * @return 
	 * @see java.lang.Object#toString() 
	 */
	@Override
	public String toString() {
		return "Users [uid=" + uid + ", uname=" + uname + "]";
	}
	
	
}

hibernate.cfg.xml

<hibernate-configuration>
    <session-factory>
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.password">root</property>
        <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/hibernate</property>
        <property name="hibernate.connection.username">root</property>
        <property name="show_sql">true</property>
        <property name="format_sql">true</property>
        
        <mapping resource="club/lygangdai/pojo/Roles.hbm.xml"/>
        <mapping resource="club/lygangdai/pojo/Users.hbm.xml"/>
    </session-factory>
</hibernate-configuration>