hibernate 一对多双向

最新推荐文章于 2019-11-15 16:49:37 发布

原创最新推荐文章于 2019-11-15 16:49:37 发布 · 242 阅读

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本文详细解析了Hibernate框架中一对多双向映射的实现方式，通过具体代码示例展示了Group类与User类之间的关联关系，深入探讨了实体类的定义及注解使用。

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一对多双向的话，就不用区分一对多还是多对一了。这个好理解。

package com.bjsxt.hibernate;

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>();
	@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;
	}
	@OneToMany(mappedBy="group")
	
	public Set<User> getUsers() {
		return users;
	}
	public void setUsers(Set<User> users) {
		this.users = users;
	}
}

package com.bjsxt.hibernate;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
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
	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;
	}
}