hibernate一对多关系配置

一、     表信息

　　公司表

cId	cName	cAdress
Null	Null	Null

　　　　　　　　　　　　表t_company

　　员工表　

sId	sName	sAge	cId
Null	Null	Null	Nulls

　　　　　　　　　　　　表t_staff

　　公司-员工：一对多关系，一个公司对应多个员工。外键设在多的一方。

 

二、       实体类

 

Company类

package dao;

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

public class Company {
    private Integer cId;
    private String cName;
    private String cAdress;
    private Set<Staff> setStaff = new HashSet<Staff>();
    public Integer getcId() {
        return cId;
    }
    public Set<Staff> getSetStaff() {
        return setStaff;
    }
    public void setSetStaff(Set<Staff> setStaff) {
        this.setStaff = setStaff;
    }
    public void setcId(Integer cId) {
        this.cId = cId;
    }
    public String getcName() {
        return cName;
    }
    public void setcName(String cName) {
        this.cName = cName;
    }
    public String getcAdress() {
        return cAdress;
    }
    public void setcAdress(String cAdress) {
        this.cAdress = cAdress;
    }
}

Staff类

package dao;

public class Staff {
    private Integer sId;
    private String sName;
    private Integer sAge;
    private Company company;
    public Company getCompany() {
        return company;
    }
    public void setCompany(Company company) {
        this.company = company;
    }
    public Integer getsId() {
        return sId;
    }
    public void setsId(Integer sId) {
        this.sId = sId;
    }
    public String getsName() {
        return sName;
    }
    public void setsName(String sName) {
        this.sName = sName;
    }
    public Integer getsAge() {
        return sAge;
    }
    public void setsAge(Integer sAge) {
        this.sAge = sAge;
    }
}

Hibernate要求使用集合表示多的数据，用Set集合表示

 

三、       配置文件

映射配置文件：

Company.hbm.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC 
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
 <hibernate-mapping>
     <class name="dao.Company" table="t_company">
     <id name="cId" column="cId"><generator class="native"></generator></id>
     <property name="cName" column="cName"></property>
     <property name="cAdress" column="cAdress"></property>
     <set name="setStaff">
     <key column="cId"></key>
     <one-to-many class="dao.Staff"/>
     </set>
     </class>
 </hibernate-mapping>

Staff.hbml.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC 
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
    <class name="dao.Staff" table="t_staff">
    <id name="sId" column="sId"><generator class="native"></generator></id>
    <property name="sName" column="sName"></property>
    <property name="sAge" column="sAge"></property>
    <many-to-one name="company" class="dao.Company" column="cId"></many-to-one>
    </class>
</hibernate-mapping>

核心配置文件：

Hibernate.cfg.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/hibernate?useUnicode=true&amp;characterEncoding=utf-8</property>
        <property name="hibernate.connection.username">root</property>
        <property name="hibernate.connection.password">123</property>
        <property name="hibernate.show_sql">true</property>
        <property name="hibernate.format_sql">true</property>
        <property name="hibernate.hbm2ddl.auto">update</property>
        <mapping resource="dao/Company.hbm.xml"/>
        <mapping resource="dao/Staff.hbm.xml"/>
    </session-factory>
</hibernate-configuration>

在一对多的一方配置<set>

在多对一的乙方配置<many-to-one>