正文
【Hibernate】--一对一关联、联合主键
提示：扫一扫查出行【扫一扫了解最新限行尾号】
复制提示
一、数据模型
1.学生信息模型（编号、名称、身份信息）
public class Student implements java.io.Serializable{
private static final long serialVersionUID = 1L;
private Integer sid;
private String sname;
private IdClass pid;
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 IdClass getPid() {
return pid;
}
public void setPid(IdClass pid) {
this.pid = pid;
}
}
2.身份信息模型（身份ID、省份）
public class IdClass implements java.io.Serializable{
private static final long serialVersionUID = 1L;
private String pid;
private String provience;
private Student stu;
public String getPid() {
return pid;
}
public void setPid(String pid) {
this.pid = pid;
}
public String getProvience() {
return provience;
}
public void setProvience(String provience) {
this.provience = provience;
}
public Student getStu() {
return stu;
}
public void setStu(Student stu) {
this.stu = stu;
}
}
二、单向唯一关联
A.配置文件描述
<hibernate-mapping package="com.hibernate.orm">
<class name="Student" table="student">
<id name="sid" type="java.lang.Integer" length="50">
<generator class="identity"/>
</id>
<property name="sname" column="s_name" not-null="false" type="java.lang.String"/>
<!-- 主控方：这里虽然使用了many2one,但是设置了unique为true，这样就只能是单向一对一关联了 -->
<many-to-one name="pid" column="pid" cascade="all" unique="true"/>
</class>
</hibernate-mapping>
<hibernate-mapping package="com.hibernate.orm">
<class name="IdClass" table="id_class_info">
<id name="pid" type="java.lang.String" length="20">
<generator class="assigned"/>
</id>
<property name="provience" column="provience" not-null="false" type="java.lang.String"/>
<!-- 被控方：指定stu属性被IdClass中的pid属性控制 -->
<one-to-one name="stu" property-ref="pid"/>
</class>
</hibernate-mapping>
B.注解描述（在相关的属性上添加注解描述）
@Entity
@Table(name="student",catalog="study")
public class Student implements java.io.Serializable{
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
private Integer sid;
@Column(name="s_name",nullable=false, length=11)
private String sname;
@OneToOne(cascade=CascadeType.ALL)
@JoinColumn(name="pid", nullable=false, unique=true)
private IdClass pid;
//......getter和setter方法省略............
}
@Entity
@Table(name="id_class_info",catalog="study")
public class IdClass implements java.io.Serializable{
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(generator="pid")
@GenericGenerator(name="pid",strategy="assigned")
private String pid;
@Column(name="provience", length=40, nullable=false)
private String provience;
//只要是双向关联就一定要指定mappedBy,将控制权交给指定的一方
@OneToOne(mappedBy="pid")
private Student stu;
//......getter和setter方法省略............
}
public class Student implements java.io.Serializable{
private static final long serialVersionUID = 1L;
private Integer sid;
private String sname;
private IdClass pid;
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 IdClass getPid() {
return pid;
}
public void setPid(IdClass pid) {
this.pid = pid;
}
}
2.身份信息模型（身份ID、省份）
public class IdClass implements java.io.Serializable{
private static final long serialVersionUID = 1L;
private String pid;
private String provience;
private Student stu;
public String getPid() {
return pid;
}
public void setPid(String pid) {
this.pid = pid;
}
public String getProvience() {
return provience;
}
public void setProvience(String provience) {
this.provience = provience;
}
public Student getStu() {
return stu;
}
public void setStu(Student stu) {
this.stu = stu;
}
}
A.配置文件描述
<hibernate-mapping package="com.hibernate.orm">
<class name="Student" table="student">
<id name="sid" type="java.lang.Integer" length="50">
<generator class="identity"/>
</id>
<property name="sname" column="s_name" not-null="false" type="java.lang.String"/> <!-- 主控方：这里虽然使用了many2one,但是设置了unique为true，这样就只能是单向一对一关联了 -->
<many-to-one name="pid" column="pid" cascade="all" unique="true"/>
</class>
</hibernate-mapping>
<hibernate-mapping package="com.hibernate.orm">
<class name="IdClass" table="id_class_info">
<id name="pid" type="java.lang.String" length="20">
<generator class="assigned"/>
</id>
<property name="provience" column="provience" not-null="false" type="java.lang.String"/> <!-- 被控方：指定stu属性被IdClass中的pid属性控制 -->
<one-to-one name="stu" property-ref="pid"/> </class>
</hibernate-mapping>
B.注解描述（在相关的属性上添加注解描述）
@Entity
@Table(name="student",catalog="study")
public class Student implements java.io.Serializable{ private static final long serialVersionUID = 1L; @Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
private Integer sid; @Column(name="s_name",nullable=false, length=11)
private String sname; @OneToOne(cascade=CascadeType.ALL)
@JoinColumn(name="pid", nullable=false, unique=true)
private IdClass pid; //......getter和setter方法省略............
}
@Entity
@Table(name="id_class_info",catalog="study")
public class IdClass implements java.io.Serializable{ private static final long serialVersionUID = 1L; @Id
@GeneratedValue(generator="pid")
@GenericGenerator(name="pid",strategy="assigned")
private String pid; @Column(name="provience", length=40, nullable=false)
private String provience; //只要是双向关联就一定要指定mappedBy,将控制权交给指定的一方
@OneToOne(mappedBy="pid")
private Student stu; //......getter和setter方法省略............
}
注：一对一关联配置参见网友博客：http://blog.csdn.net/dreamcatchergo/article/details/13627709
三、双向一对一外键关联
单向的基础上，添加另一方为被控方，通过one-to-one实现被控方描述
A.配置文件描述
<!-- 被控方：指定stu属性被IdClass中的pid属性控制 -->
<one-to-one name="stu" property-ref="pid"/>
B.注解描述
//只要是双向关联就一定要指定mappedBy,将控制权交给指定的一方
@OneToOne(mappedBy="pid")
private Student stu;
四、联合主键
添加主键类，在身份信息模型中添加血型，将身份ID和血型作为联合主键，代码如下
public class IdCardPK implements Serializable{
private static final long serialVersionUID = 1L;
private String pid;
private String bloodType; //血型
//*******************
}
A.配置文件描述
<hibernate-mapping package="com.hibernate.orm.ufk">
<class name="IdClass" table="id_class_info">
<!-- 联合主键 -->
<composite-id name="idCardPK" class="com.hibernate.orm.ufk.IdCardPK">
<key-property name="pid" column="p_id" length="20" type="string"/>
<key-property name="bloodType" column="blood_type" length="10" type="string"/>
<!-- 不能再指定 generator
<generator class="assigned"/>
-->
</composite-id>
<property name="provience" column="provience" not-null="false" type="string"/>
</class>
</hibernate-mapping>
student方修改关联配置，将原有的pid做如下修改：
<many-to-one name="pid" cascade="all">
<column name="p_id" unique="true"/>
<column name="blood_type"/>
</many-to-one>
B.注解描述
主键类配置如下，注意添加getter和setter方法：
@Embeddable
public class IdCardPK implements Serializable{
private static final long serialVersionUID = 1L;
@Column(name="p_id",nullable=false, length=20)
private String pid;
@Column(name="blood_type",nullable=false)
private String bloodType; //血型
}
身份信息修改如下
@EmbeddedId
private IdCardPK idCardPK;
学生信息模型关联身份信息配置：
@OneToOne(cascade=CascadeType.ALL)
@JoinColumns({
@JoinColumn(name="p_id",referencedColumnName="p_id"),
@JoinColumn(name="blood_type",referencedColumnName="blood_type")
})
private IdClass pid;
五、组件关联（将POJO类中的属性作为添加到某实体类）
定义一个组件类POJO，代码如下：
public class IdClass{
private String provience;
private String bloodType;
public String getProvience() {
return provience;
}
public void setProvience(String provience) {
this.provience = provience;
}
public String getBloodType() {
return bloodType;
}
public void setBloodType(String bloodType) {
this.bloodType = bloodType;
}
}
A.配置文件描述
将POJO中的属性作为student的属性，配置如下：
<hibernate-mapping package="com.hibernate.orm.component">
<class name="Student" table="student">
<id name="sid" type="integer" length="50">
<generator class="identity"/>
</id>
<property name="sname" column="s_name" not-null="false" type="string"/>
<!-- 组件关联配置 -->
<component name="pid" class="IdClass">
<property name="provience" column="provience" length="20"/>
<property name="bloodType" column="blood_type" length="10"></property>
</component>
</class>
</hibernate-mapping>
B.注解描述，通过Embedded关联组件
//和组件关联
@Embedded
private IdClass pid;
<!-- 被控方：指定stu属性被IdClass中的pid属性控制 -->
<one-to-one name="stu" property-ref="pid"/>
B.注解描述
//只要是双向关联就一定要指定mappedBy,将控制权交给指定的一方
@OneToOne(mappedBy="pid")
private Student stu;
四、联合主键
public class IdCardPK implements Serializable{
private static final long serialVersionUID = 1L;
private String pid;
private String bloodType; //血型
//*******************
}
A.配置文件描述
<hibernate-mapping package="com.hibernate.orm.ufk">
<class name="IdClass" table="id_class_info">
<!-- 联合主键 -->
<composite-id name="idCardPK" class="com.hibernate.orm.ufk.IdCardPK">
<key-property name="pid" column="p_id" length="20" type="string"/>
<key-property name="bloodType" column="blood_type" length="10" type="string"/> <!-- 不能再指定 generator
<generator class="assigned"/>
-->
</composite-id> <property name="provience" column="provience" not-null="false" type="string"/>
</class>
</hibernate-mapping>
student方修改关联配置，将原有的pid做如下修改：
<many-to-one name="pid" cascade="all">
<column name="p_id" unique="true"/>
<column name="blood_type"/>
</many-to-one>
B.注解描述
主键类配置如下，注意添加getter和setter方法：
@Embeddable
public class IdCardPK implements Serializable{ private static final long serialVersionUID = 1L; @Column(name="p_id",nullable=false, length=20)
private String pid; @Column(name="blood_type",nullable=false)
private String bloodType; //血型 }
身份信息修改如下
@EmbeddedId
private IdCardPK idCardPK;
学生信息模型关联身份信息配置：
@OneToOne(cascade=CascadeType.ALL)
@JoinColumns({
@JoinColumn(name="p_id",referencedColumnName="p_id"),
@JoinColumn(name="blood_type",referencedColumnName="blood_type")
})
private IdClass pid;
五、组件关联（将POJO类中的属性作为添加到某实体类）
public class IdClass{
private String provience;
private String bloodType;
public String getProvience() {
return provience;
}
public void setProvience(String provience) {
this.provience = provience;
}
public String getBloodType() {
return bloodType;
}
public void setBloodType(String bloodType) {
this.bloodType = bloodType;
}
}
A.配置文件描述
<hibernate-mapping package="com.hibernate.orm.component">
<class name="Student" table="student">
<id name="sid" type="integer" length="50">
<generator class="identity"/>
</id>
<property name="sname" column="s_name" not-null="false" type="string"/> <!-- 组件关联配置 -->
<component name="pid" class="IdClass">
<property name="provience" column="provience" length="20"/>
<property name="bloodType" column="blood_type" length="10"></property>
</component>
</class>
</hibernate-mapping>
B.注解描述，通过Embedded关联组件
//和组件关联
@Embedded
private IdClass pid;
