多對一的映射：
1： 在多的類中寫加入一的類作爲屬性
2：depart一的一方不寫其他屬性只寫自己的屬性 自己的映射文件也是隻寫自己的映射
3：emp多的一方映射文件加入<many-to-one name="depart" column="depart_id"/>
column="depart_id"不寫的話就默認字段爲depart
代碼如下：
Department類一的一方
package Entitys;
public class Department {
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;
}
}
映射文件：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="Entitys">
<class name="Department">
<id name="id">
<generator class="native"/>
</id>
<property name="name"/>
</class>
</hibernate-mapping>
Employee多的一方
package Entitys;
public class Employee {
private int id;
private String name;
private Department depart;
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 Department getDepart() {
return depart;
}
public void setDepart(Department depart) {
this.depart = depart;
}
}
映射文件：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="Entitys">
<class name="Employee">
<id name="id">
<generator class="native"/>
</id>
<property name="name"/>
<many-to-one name="depart" column="depart_id"/>
</class>
</hibernate-mapping>
/*
* 在對應的方法中，初始化代理就可以在查詢完返回對象後可以
* 在在取得關聯對象的信息，不必只在session中
*/
Hibernate.initialize(emp.getDepart());//是對應的屬性的類
如果有<many-to-one name="depart" column="depart_id" not-null="true"/>
那麼在必須有depart這個屬性，並且在session中保存數據時s.save(depart)必須在s.save(emp)中要確保在emp有depart字段