hibernate_1300_one2many_uni

最新推荐文章于 2019-06-27 15:27:26 发布

diao21

最新推荐文章于 2019-06-27 15:27:26 发布

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分类专栏： hibernate 文章标签： hibernate

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本文介绍了一个使用Hibernate框架实现的多对多关系映射示例，包括Group和User两个类之间的关联关系及其对应的XML配置文件。文章展示了如何通过Hibernate进行数据库表的创建，并详细解释了各部分代码的作用。


package com.bjsxt.hibernate;

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

public class Group {
	private int id;
	private String name;
	private Set<User> users = new HashSet<User>();

	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}

	public Set<User> getUsers() {
		return users;
	}
	public void setUsers(Set<User> users) {
		this.users = users;
	}
}


package com.bjsxt.hibernate;

public class User {
	private int id;
	private String name;

	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
}


Group.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
	<class name="com.bjsxt.hibernate.Group" table="t_group">
		<id name="id">
			<generator class="native"></generator>
		</id>

		<property name="name"></property>
		<set name="users">
			<key column="groupId"></key>
			<one-to-many class="com.bjsxt.hibernate.User"/>
		</set>
    </class>

</hibernate-mapping>


User.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
	<class name="com.bjsxt.hibernate.User" table="t_user">
		<id name="id">
			<generator class="native"></generator>
		</id>

		<property name="name"></property>

    </class>

</hibernate-mapping>


14:56:07,464  INFO org.hibernate.tool.hbm2ddl.SchemaExport:154 - Running hbm2ddl schema export
14:56:07,466 DEBUG org.hibernate.tool.hbm2ddl.SchemaExport:170 - import file not found: /import.sql
14:56:07,466  INFO org.hibernate.tool.hbm2ddl.SchemaExport:179 - exporting generated schema to database
14:56:07,612 DEBUG org.hibernate.tool.hbm2ddl.SchemaExport:303 - 
    alter table t_user 
        drop 
        foreign key FKCB63CCB6C3D18669
14:56:07,620 DEBUG org.hibernate.tool.hbm2ddl.SchemaExport:288 - Unsuccessful: alter table t_user drop foreign key FKCB63CCB6C3D18669
14:56:07,620 DEBUG org.hibernate.tool.hbm2ddl.SchemaExport:289 - Table 'hibernate.t_user' doesn't exist
14:56:07,620 DEBUG org.hibernate.tool.hbm2ddl.SchemaExport:303 - 
    drop table if exists t_group
14:56:07,624 DEBUG org.hibernate.tool.hbm2ddl.SchemaExport:303 - 
    drop table if exists t_user
14:56:07,626 DEBUG org.hibernate.tool.hbm2ddl.SchemaExport:303 - 
    create table t_group (
        id integer not null auto_increment,
        name varchar(255),
        primary key (id)
    )
14:56:07,731 DEBUG org.hibernate.tool.hbm2ddl.SchemaExport:303 - 
    create table t_user (
        id integer not null auto_increment,
        name varchar(255),
        groupId integer,
        primary key (id)
    )
14:56:07,806 DEBUG org.hibernate.tool.hbm2ddl.SchemaExport:303 - 
    alter table t_user 
        add index FKCB63CCB6C3D18669 (groupId), 
        add constraint FKCB63CCB6C3D18669 
        foreign key (groupId) 
        references t_group (id)
14:56:07,983  INFO org.hibernate.tool.hbm2ddl.SchemaExport:196 - schema export complete