Hibernate基于主键来进行映射的例子

最新推荐文章于 2020-06-08 11:01:47 发布

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本文介绍了一对一关联映射的实现方式，通过两个Java类People和IdCard及对应的Hibernate映射文件，展示了如何在数据库中实现身份证与个人的一对一关系。包括配置主键、外键以及级联操作。

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人和身份证的问题

t_people

pId pName

t_idcard

pId(primary key fk) cardNum

People.java

public class People {
	private int pId;
	private String name;
	private IdCard idCard;
	public int getpId() {
		return pId;
	}
	public void setpId(int pId) {
		this.pId = pId;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public IdCard getIdCard() {
		return idCard;
	}
	public void setIdCard(IdCard idCard) {
		this.idCard = idCard;
	}
}

IdCard.java

public class IdCard {
	private String cardNum;
	private People people;
	private int pId;
	public int getpId() {
		return pId;
	}
	public void setpId(int pId) {
		this.pId = pId;
	}
	public String getCardNum() {
		return cardNum;
	}
	public void setCardNum(String cardNum) {
		this.cardNum = cardNum;
	}
	public People getPeople() {
		return people;
	}
	public void setPeople(People people) {
		this.people = people;
	}
	@Override
	public String toString() {
		return "IdCard [cardNum=" + cardNum + ", people=" + people + ", pId=" + pId + "]";
	}
	
}

IdCard.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="cn.pzhu.one2one" >
    <class name="IdCard" table="t_card_1">
    <!-- 配置主键 -->
        <id name="pId" >
        	<!-- 表示使用别的对象的主键来作为主键 -->
            <generator class="foreign">
            	<param name="property">people</param>
            </generator>
        </id>
        <!-- 普通列 -->
        <property name="cardNum"/>
		<!-- constrained表示要作为外键 -->
		<one-to-one name="people" class="People" constrained="true" cascade="all"></one-to-one>
    </class>
</hibernate-mapping>

People.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="cn.pzhu.one2one" >
    <class name="People" table="t_people_1">
    <!-- 配置主键 -->
        <id name="pId">
        	<!-- 自增长 -->
            <generator class="native"/>
        </id>
        <!-- 普通列 -->
		<property name="name"></property>			
    </class>
</hibernate-mapping>