Hibernate的组件(Component)映射
在学习Hibernate框架时碰到了许多实际的问题,比如一个Name是由FirstName和LastName组成,或者说一个Address是有Province,City,County和The detailed address组成,那么这么复杂的属性作为实际设计中是不应该出现在一个类里,那么组件映射就出现了
下面展示组件映射的实例,User对象中的Name属性
<?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <hibernate-mapping package="com.dao"> <class name="User" table="User"> <id name="id"> <generator class="native" /> </id> <component name="name"> <property name="firstname" column="first_name"/> <property name="lastname" column="last_name" /> </component> <property name="birthday" /> </class> </hibernate-mapping>
User.java代码
1 package com.dao; 2 3 import java.util.Date; 4 5 public class User { 6 private int id; 7 private Name name; 8 private Date birthday; 9 10 public void setName(Name name) { 11 this.name = name; 12 } 13 14 public int getId() { 15 return id; 16 } 17 18 public void setId(int id) { 19 this.id = id; 20 } 21 22 public Name getName() { 23 return name; 24 } 25 26 public Date getBirthday() { 27 return birthday; 28 } 29 30 public void setBirthday(Date birthday) { 31 this.birthday = birthday; 32 } 33 }
Name的代码
package com.dao; 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; } }
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