hibernate------one-to-one（通過外鍵方式實現）

以學生和電腦爲例(Student-Computer)
建表sql語句：

DROP TABLE IF EXISTS `student`; CREATE TABLE `student` ( `id` int(11) NOT NULL auto_increment, `name` varchar(255) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; DROP TABLE IF EXISTS `computer`; CREATE TABLE `computer` ( `id` int(11) NOT NULL auto_increment, `name` varchar(255) NOT NULL, `student_id` int(11) , foreign key (`student_id`) references student(`id`), PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;

 

Student.java:

public class Student implements java.io.Serializable { private Integer id; private String name; private Computer computer; public Student() { } public Student(String name) { this.name = name; } public Integer getId() { return this.id; } public void setId(Integer id) { this.id = id; } public String getName() { return this.name; } public void setName(String name) { this.name = name; } public Computer getComputer() { return computer; } public void setComputer(Computer computer) { this.computer = computer; } }

 

Computer.java:

public class Computer implements java.io.Serializable { private Integer id; private Student student; private String name; public Computer() { } public Computer(String name) { this.name = name; } public Computer(Student student, String name) { this.student = student; this.name = name; } public Integer getId() { return this.id; } public void setId(Integer id) { this.id = id; } public Student getStudent() { return this.student; } public void setStudent(Student student) { this.student = student; } public String getName() { return this.name; } public void setName(String name) { this.name = name; } }

Student.hbm.xml:

<class name="com.domain.Student" table="student" catalog="onetoone"> <id name="id" type="java.lang.Integer"> <column name="id" /> <generator class="native" /> </id> <property name="name" type="java.lang.String"> <column name="name" not-null="true" /> </property> <!-- class可以不寫，因爲根據name的值computer(屬性)，會通過反射自動找到屬於哪個類的 --> <one-to-one cascade="delete,save-update" name="computer" class="com.domain.Computer" property-ref="student"></one-to-one> </class>

Computer.hbm.xml:

<class name="com.domain.Computer" table="computer" catalog="onetoone"> <id name="id" type="java.lang.Integer"> <column name="id" /> <generator class="native" /> </id> <property name="name" type="java.lang.String"> <column name="name" not-null="true" /> </property> <!-- many開頭的是代表該表持有外鍵 --> <many-to-one name="student" class="com.domain.Student" unique="true"> <column name="student_id" /> </many-to-one> </class>