6.Hibernate多對多關係建立

多對多關係主要是應用在不同的使用者具備多個不同的角色，比如王者榮耀中趙雲既可以拿來打野又可以拿來打上單，李元芳既可以拿來打野也可以拿來打射手，因此這期間的多個使用者具備多個角色屬性用先前的一對多關係就不能解決了，需要多對多的對映關係

1.建立資料庫表

sql語句如下

CREATE TABLE IF NOT EXISTS sys_user(
  user_id BIGINT NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT '使用者id',
  user_code VARCHAR(32) DEFAULT NULL COMMENT '使用者code值',
  user_name VARCHAR(32) DEFAULT NULL COMMENT '使用者名稱',
  user_password VARCHAR(32) DEFAULT NULL COMMENT '使用者名稱密碼',
  user_state VARCHAR(32) DEFAULT NULL COMMENT '使用者職位'
);

CREATE TABLE IF NOT EXISTS sys_role(
  role_id BIGINT NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT '職位id',
  role_name VARCHAR(32) DEFAULT NULL COMMENT '職位名稱',
  role_memo VARCHAR(32) DEFAULT NULL COMMENT '職位成員'
);

CREATE TABLE IF NOT EXISTS sys_user_role(
  user_id BIGINT NOT NULL ,
  FOREIGN KEY(user_id) REFERENCES sys_user(user_id) ON DELETE  NO ACTION ON UPDATE NO ACTION ,
  role_id BIGINT NOT NULL ,
  FOREIGN KEY (role_id) REFERENCES sys_role(role_id) ON DELETE NO ACTION ON UPDATE NO ACTION
);
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2.建立實體

建立Sys_user實體

package com.classes;

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

public class Sys_user {
	private Long user_id;
	private String user_code;
	private String user_name;
	private String user_password;
	private String user_state;
	
	private Set<Sys_role> roles  = new HashSet<Sys_role>();
	
	
	public Set<Sys_role> getRoles() {
		return roles;
	}
	public void setRoles(Set<Sys_role> roles) {
		this.roles = roles;
	}
	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 String getUser_state() {
		return user_state;
	}
	public void setUser_state(String user_state) {
		this.user_state = user_state;
	}
}
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建立Sys_role實體

package com.classes;

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

public class Sys_role {
	private Long role_id;
	private String role_name;
	private String role_memo;
	
	private Set<Sys_user>users = new HashSet<Sys_user>();
	
	public Set<Sys_user> getUsers() {
		return users;
	}
	public void setUsers(Set<Sys_user> users) {
		this.users = users;
	}
	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;
	}
}
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3.建立對映檔案

用工具建立Sys_user的對映表,建立完畢需要對原有多對多的地方進行修改

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated Mar 6, 2018 4:29:51 PM by Hibernate Tools 3.5.0.Final -->
<hibernate-mapping>
    <class name="com.classes.Sys_user" table="SYS_USER">
        <id name="user_id" type="java.lang.Long">
            <column name="USER_ID" />
            <generator class="native" />
        </id>
        <property name="user_code" type="java.lang.String">
            <column name="USER_CODE" />
        </property>
        <property name="user_name" type="java.lang.String">
            <column name="USER_NAME" />
        </property>
        <property name="user_password" type="java.lang.String">
            <column name="USER_PASSWORD" />
        </property>
        <property name="user_state" type="java.lang.String">
            <column name="USER_STATE" />
        </property>
        <set name="roles" table="sys_user_role" inverse="false" lazy="true">
            <key>
                <column name="USER_ID" />
            </key>
            <!-- <one-to-many class="com.classes.Sys_role" /> -->
            <many-to-many class="com.classes.Sys_role" column="role_id"/>
        </set>
    </class>
</hibernate-mapping>
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用工具建立Sys_role對映表，需要對多對多的地方進行修改成如下的程式碼

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated Mar 6, 2018 4:29:51 PM by Hibernate Tools 3.5.0.Final -->
<hibernate-mapping>
    <class name="com.classes.Sys_role" table="SYS_ROLE">
        <id name="role_id" type="java.lang.Long">
            <column name="ROLE_ID" />
            <generator class="native" />
        </id>
        <property name="role_name" type="java.lang.String">
            <column name="ROLE_NAME" />
        </property>
        <property name="role_memo" type="java.lang.String">
            <column name="ROLE_MEMO" />
        </property>
        <set name="users" table="sys_user_role" inverse="false" lazy="true">
            <key>
                <column name="ROLE_ID" />
            </key>
           <!--  <one-to-many class="com.classes.Sys_user" /> -->
           <many-to-many class="com.classes.Sys_user" column="user_id"/>
        </set>
    </class>
</hibernate-mapping>
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4.在核心配置檔案中新增入對映檔案

<?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>
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.password">lwhong1017</property>
        <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/myblog?useSSL=true</property>
        <property name="hibernate.connection.username">root</property>
        <mapping resource="com/classes/Sys_role.hbm.xml"/>
        <mapping resource="com/classes/Sys_user.hbm.xml"/>
    </session-factory>
</hibernate-configuration>
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5.引入封裝的資料工具以及編寫測試程式碼

5.1資料工具

package com.HibernateUtils;

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

import com.classes.Sys_role;
import com.classes.Sys_user;

public class DButils {
	private static SessionFactory sessionFactory;
	private static Session session;
	public static Session getSession() {
		return session;
	}

	public static void setSession(Session session) {
		DButils.session = session;
	}

	static {
		Configuration configuration = new Configuration().configure();
		sessionFactory = configuration.buildSessionFactory();
	}
	static {
		session = sessionFactory.openSession();
	}
	
	public void SaveData() {
		System.out.println("aaaaa----");
		Session session = this.getSession();
		Transaction transaction = session.beginTransaction();
		
		// 1.建立使用者
		Sys_user user1 = new Sys_user();
		user1.setUser_name("趙雲");
		
		Sys_user user2 = new Sys_user();
		user2.setUser_name("馬克");
		
		Sys_user user3 = new Sys_user();
		user3.setUser_name("干將莫邪");
		
		// 2.建立角色職位
		Sys_role role1 = new Sys_role();
		role1.setRole_name("ADC射手");
		
		Sys_role role2 = new Sys_role();
		role2.setRole_name("打野");
		
		Sys_role role3 = new Sys_role();
		role3.setRole_name("中單");
		
		Sys_role role4 = new Sys_role();
		role4.setRole_name("戰士");
		
		user1.getRoles().add(role2);
		user1.getRoles().add(role4);
		
		user2.getRoles().add(role3);
		user2.getRoles().add(role2);
		
		user3.getRoles().add(role3);
		
		session.save(user1);
		session.save(user2);
		session.save(user3);
		session.save(role1);
		session.save(role2);
		session.save(role3);
		session.save(role4);
		
		transaction.commit();
		System.out.println("bbbbb----");
	}
}
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5.2測試類

package com.testHibernate;

import com.HibernateUtils.DButils;

public class testHib {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		DButils dButils = new DButils();
		dButils.SaveData();
	}

}
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因為有前面出現的一些坑本篇也出線了一些坑但是按照先前的一些思路還是比較順利的解決了，多對多的主要是在hbm配置時候需要column對應各個屬性 WiHongNoteBook