public class Person {private int personid;private String name;private int age;//在Person对象中有Address对象的关联信息private Address address;public class Address{//Address对象中没有Person对象的关联信息private int addressid;private String addressdetail;

<hibernate-mapping><class name="com.entity.Person" table="PERSON"><id name="personid" column="presonid"> <!--基于主键关联时，主键生成策略是foreign，表明根据关联类生成主键--><generator class="foreign"><!--关联持久化类的属性名--><param name="property">address</param></generator></id><property name="name"/><property name="age"/><!--constrained设定为true，表示的主键必须与Person中对应资料的主键相同。--><one-to-one name="address" constrained="true"/></class>
</hibernate-mapping>

public class Person implements java.io.Serializable { private Long id; private String name; //双向关联中Person对象中有Adderss对象的关联信息  private Address address;public class Address implements java.io.Serializable { private Long id; //Adderss对象中也有Person对象的关联信息  private Person person; private String detail;

<hibernate-mapping> <class name="entity.Person" table="person"> <id name="id" type="java.lang.Long"> <column name="id" /> <generator class="identity" /> </id> <property name="name" type="java.lang.String"> <column name="name" length="24" not-null="true"> <comment>姓名</comment> </column> </property> <one-to-one name="address"/> </class>
</hibernate-mapping>

<hibernate-mapping> <class name="entity.Address" table="address" catalog="mydb"> <id name="id" type="java.lang.Long"> <column name="id" />  <!-- class="foreign": 一对一主键映射中，使用另外一个相关联的对象的标识符 --> <generator class="foreign"> <param name="property">person</param> </generator> </id> <property name="detail" type="java.lang.String"> <column name="detail" length="120" not-null="true"> <comment>详细地址</comment> </column> </property>  <!-- 表示在address表存在一个外键约束，外键参考相关联的表person --> <one-to-one name="person" constrained="true" /> </class>
</hibernate-mapping>

<hibernate-configuration> <session-factory> <property name="connection.username">root</property> <property name="connection.url"> jdbc:mysql://localhost:3306/testdb </property> <property name="dialect"> org.hibernate.dialect.MySQLDialect </property> <property name="connection.password">xiaohui</property> <property name="connection.driver_class"> com.mysql.jdbc.Driver </property> <property name="show_sql">true</property> <property name="format_sql">true</property> 

　　 <!--在hibernate.cfg.xml中配置hbm.xml文件--><mapping resource="com/entity/Person.hbm.xml" /> <mapping resource="com/entity/Address.hbm.xml" /> </session-factory> </hibernate-configuration>

public class Person {private int personid;private String name;private int age;private Address address;public class Address{private int addressid;private String addressdetail;

Address.hbm.xml<!--address中不做任何配置所以我们省略-->

　　…………………………
<!--单向关联和双向关联的区别在于单向关联只在一方配置双向关联两方都要配置-->
Person.hbm.xml
<hibernate-mapping> <class name="com.entity.Person" table="PERSON"> <id name="personid"> <generator class="identity"/> </id> <property name="name"/> <property name="age"/>  <!--用来映射关联PO column是Address在该表中的外键列名,增加unique变成唯一的--> <many-to-one name="address" unique="true"/> </class>
</hibernate-mapping>

public class Person implements java.io.Serializable { private Long id; private String name; private Address address;public class Address implements java.io.Serializable { private Long id; private Person person; private String detail;

Person.hbm.xml
<hibernate-mapping> <class name="com.entity.Person" table="person"> <id name="personid" type="java.lang.Long"> <column name="personid" /> <generator class="identity" /> </id> <property name="name" type="java.lang.String"> <column name="name" length="24" not-null="true"> <comment>姓名</comment> </column> </property> 　　<!--双向关联配置--><one-to-one name="address" /> </class>
</hibernate-mapping>Address.hbm.xml
<hibernate-mapping> <class name="com.entity.Address" table="address" catalog="testdb"> <id name="addressid" type="java.lang.Long"> <column name="addressid" /> <generator class="identity" /> </id> <property name="detail" type="java.lang.String"> <column name="detail" length="120" not-null="true"> <comment>详细地址</comment> </column> </property> <many-to-one name="person" class="entity.Person" unique="true"> <column name="personid"> <comment>人的ID</comment> </column> </many-to-one> </class>
</hibernate-mapping>

<hibernate-configuration> <session-factory> <property name="connection.username">root</property> <property name="connection.url"> jdbc:mysql://localhost:3306/testdb </property> <property name="dialect"> org.hibernate.dialect.MySQLDialect </property> <property name="connection.password">xiaohui</property> <property name="connection.driver_class"> com.mysql.jdbc.Driver </property> <property name="show_sql">true</property> <property name="format_sql">true</property> <!--在hibernate.cfg.xml中配置hbm.xml文件--><mapping resource="com/entity/Person.hbm.xml" /> <mapping resource="com/entity/Address.hbm.xml" /> </session-factory> </hibernate-configuration>

public class Classes {  private int id;  private String name;     //Set支持延迟加载因为多个学生所以我们用Set集合关联  private Set students;
}  

public class Student {  private int id;  private String name;
}  

<hibernate-mapping>  <class name="com.hibernate.Classes" table="t_classes">  <id name="id">  <generator class="native"/>  </id>  <property name="name"/>  <set name="students">  <key column="classesid"></key>  <one-to-many class="com.hibernate.Student"></one-to-many>  </set>  </class>
</hibernate-mapping>  

public class Classes {  private int id;  private String name;     //Set支持延迟加载    private Set<Student> students;
}
public class Student {  private int id;  private String name; //添加class对象关联信息因为是一方所以我们用一个对象关联private Classes classes;
}  

<hibernate-mapping>  <class name="com.hibernate.Student" table="t_student">  <id name="id">  <generator class="native"/>  </id>  <property name="name"/>  <!-- 在多的一端Student中添加一行新的Classes列 ,并且列的名称要和Classes.hbm.xml的列明相同-->  <many-to-one name="classes" column="classesid"></many-to-one>  </class>
</hibernate-mapping>  

public class Teacher {private int id;private String name;private Set<Student> students = new HashSet<Student>();
｝public class Student {private int id;private String name;private String title;
｝

<hibernate-mapping>  <class name="com.hibernate.Teacher" table="t_teacher">  <id name="id">  <generator class="native"/>  </id>  <property name="name"/>  　　　　　<!--生成一张新表存放两个关联对象的ID--><set name="students" table="Teacher_Sutdent">  　　　　　　　<!--将Teacher表的外键关联 注意不是对象的属性是表中的字段--><key column="teacher_id"></key>  　　　　　　　<!--将Student表的外键关联 注意不是对象的属性是表中的字段--> 　　　　　　　<many-to-many class="com.hibernate.Student" column="student_id"></many-to-many> 　　　　  </set> 　　　</class> </hibernate-mapping>

public class Teacher {private int id;private String name;private Set<Student> students = new HashSet<Student>();
｝public class Student {private int id;private String name;private String title;private Set<Teacher> teachers = new HashSet<Teacher>();
｝

<hibernate-mapping>  <class name="com.hibernate.Student" table="t_student">  <id name="id">  <generator class="native"/>  </id>  <property name="name"/>  <!--生成一张新表存放两个表的Id--><set name="teachers" table="Teacher_Student">  <!--将Teacher表的外键关联 注意不是对象的属性是表中的字段--><key column="student_id"></key>  <!--将Student表的外键关联 注意不是对象的属性是表中的字段--> <many-to-many class="com.hibernate.Teacher" column="teacher_id"></many-to-many> </set> </class>
</hibernate-mapping>

public class Department {  private int id;  private String name;
}  public class Employee {  private int id;  private String name;  private Department depart;//注意这里是以部门的对象来作为员工的属性的，这个思想很关键，是建立起部门和员工关联的关键  

}  

<hibernate-mapping package="com.suo.domain">  <class name="Employee">  <id name="id">  <generator class="native"/>  </id>  <property name="name"/>  <many-to-one name="depart"></many-to-one>  <!-- many-to-one指明了外键 ，会根据反射机制，找到要和Employee建立多对一关系的类，该列默认的是可以为空的-->  </class>  </hibernate-mapping>  

public class Department {  private int id;  private String name;private Set<Employee> emps;//用集合来存储员工
}  public class Employee {  private int id;  private String name;  private Department depart;//注意这里是以部门的对象来作为员工的属性的，这个思想很关键，是建立起部门和员工关联的关键  

}  

<hibernate-mapping package="com.suo.domain">  <class name="Department">  <id name="id">  <generator class="native"/>  </id>  <property name="name"/>    <set name="emps">  <key column="depart_id"/><!-- key指明了员工表中的外键-->  <one-to-many class="Employee"/><!-- one-to-many指明了和哪个类进行一对多的映射 -->  </set>  <!--   用set标签表示Department中的员工集合的属性，这个属性并没有映射到数据库中的部门表中，  即部门表中，并没有emps这样的一个列。  -->  </class>  </hibernate-mapping>