一対多と多対一の双方向関連付け
1つのグループに複数のユーザーがいる1つのユーザーは1つのグループにしか属しません.ユーザーテーブルにグループがある外部キー
Annotation構成:
Xml構成:
Annotation構成:
package com.zchen.hibernate.mtootm;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;
import javax.persistence.Table;
@Entity
@Table(name="T_GROUP")
public class Group {
private int id;
private String name;
private Set<User> users = new HashSet<User>();
@OneToMany(mappedBy="group")
public Set<User> getUsers() {
return users;
}
public void setUsers(Set<User> users) {
this.users = users;
}
@Id
@GeneratedValue
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;
}
}
package com.zchen.hibernate.mtootm;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
@Entity
@Table(name="T_USER")
public class User {
private int id;
private String name;
private Group group;
@ManyToOne
@JoinColumn(name="GROUP_ID")
public Group getGroup() {
return group;
}
public void setGroup(Group group) {
this.group = group;
}
@Id
@GeneratedValue
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;
}
}
Xml構成:
<?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 package="com.zchen.hibernate.mtootm">
<class name="Group" table="T_GROUP">
<id name="id" column="ID">
<generator class="native">
</generator>
</id>
<property name="name" column="NAME"/>
<set name="users">
<key column="GROUP_ID"></key>
<one-to-many class="com.zchen.hibernate.mtootm.User"/>
</set>
</class>
</hibernate-mapping>
<?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 package="com.zchen.hibernate.mtootm">
<class name="User" table="T_USER">
<id name="id" column="ID">
<generator class="native">
</generator>
</id>
<property name="name" column="NAME"/>
<many-to-one name="group" column="GROUP_ID"></many-to-one>
</class>
</hibernate-mapping>
<?xml version="1.0"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory name="">
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql:///db_czbk_hibernate</property>
<property name="connection.username">root</property>
<property name="connection.password">1234</property>
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hbm2ddl.auto">create</property>
<property name="current_session_context_class">thread</property>
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<property name="show_sql">true</property>
<mapping class="com.zchen.hibernate.mtootm.Group" />
<mapping class="com.zchen.hibernate.mtootm.User" />
<!-- <mapping resource="com/zchen/hibernate/mtootm/Group.hbm.xml" />
<mapping resource="com/zchen/hibernate/mtootm/User.hbm.xml" /> -->
</session-factory>
</hibernate-configuration>
package com.zchen.hibernate;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.junit.Test;
public class Snippet {
@Test
public void testSchemaExport(){
new SchemaExport(new AnnotationConfiguration().configure()).create(true, true);
}
}