一对多单向关联

表结构

t_group表

'CREATE TABLE `t_group` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8'

 

t_user表

'CREATE TABLE `t_user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL,
  `groupID` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `FK_taq8kc1am04kmcpiroa7htlmm` (`groupID`),
  CONSTRAINT `FK_taq8kc1am04kmcpiroa7htlmm` FOREIGN KEY (`groupID`) REFERENCES `t_group` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8'

 

XML方法

Group类

package hibernate.entities;

import java.util.HashSet;
import java.util.Set;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;

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;
	}
	
	
}

 

User类

package hibernate.entities;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;

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://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="hibernate.entities">
    <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="groupID"></key>
       	<one-to-many class="hibernate.entities.User"/>
       </set>
       
    </class>
</hibernate-mapping>

 

User.hbm.xml

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

<hibernate-mapping package="hibernate.entities">
    <class name="User" table="t_user">
       <id name="id" column="id">
       	<generator class="native"></generator>
       </id>
       
       <property name="name" column="name"/>
       
    </class>
</hibernate-mapping>

 

Annotation方法

package hibernate.entities;

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

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
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>();
	
	@Id
	@GeneratedValue(strategy=GenerationType.AUTO)
	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;
	}
	
	@OneToMany
	@JoinColumn(name="groupId")
	public Set<User> getUsers() {
		return users;
	}
	public void setUsers(Set<User> users) {
		this.users = users;
	}
	
	
}

 

package hibernate.entities;

import javax.persistence.Column;
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;
	
	@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;
	}
	
}