传智播客Hibernate视频教程学习笔记23

组件关联关系的映射：

类似于一对一关系，但是两个对象的属性保存在一张表中，比如：

People.java

package domain;

public class People {
private int id;
private Name name;

public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public Name getName() {
return name;
}
public void setName(Name name) {
this.name = name;
}
}

Name.java

package domain;

public class Name {
private String firstName;
private String lastName;

public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
}

这个样子，表结构其实只有People一张表，firstName lastName无非是其中的两个字段罢了，pojo这样设计无非是让逻辑更清晰一些，分的更细致一些而已。下面来看这种组件关联关系的映射文件

People.hbm.xml

<?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="domain">
<class name="People">
<id name="id">
<generator class="native"/>
</id>
<component name="name">
<property name="firstName" column="first_name"></property>
<property name="lastName" column="last_name"></property>
</component>
</class>
</hibernate-mapping>

用到了component标签，也比较简单，这种情况也算少的，所以带过。