第七章Hibernate 组件（component）映射
第七章 Hibernate组件（component）映射
- 组件（Component）映射的单向关联
- 组件映射的双向关联
- 组件集合映射
* 组件（Component）
- 除了粗粒度的对象模型设计（一个表映射成一个持久化类）之外，还可以采用细粒度的 对象模型，把一个表映射成两个或者多个类。
- 被细化出来的类，可以成为组件（Component）
User类：
public class User implements java.io.Serializable {
private Integer id;
private String username;
private String password;
private Profile profile;
public User(){}
public Profile getProfile() {
return profile;
}
public void setProfile(Profile profile) {
this.profile = profile;
}
public Integer getId() {
return this.id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUsername() {
return this.username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return this.password;
}
public void setPassword(String password) {
this.password = password;
}
}Profile类：
public class Profile {
private String email;
private String address;
private String postcode;
private String mobile;
private String phone;
//加上该属性，修改配置文件，即双向关联
private User user;
public Profile(){}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getPostcode() {
return postcode;
}
public void setPostcode(String postcode) {
this.postcode = postcode;
}
public String getMobile() {
return mobile;
}
public void setMobile(String mobile) {
this.mobile = mobile;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
}Hibernate配置文件：
<hibernate-mapping>
<class name="com.crazy.User" table="USERS2" schema="SCOTT">
<id name="id" type="java.lang.Integer">
<column name="ID" precision="8" scale="0" />
<generator class="increment" />
</id>
<property name="username" type="java.lang.String">
<column name="USERNAME" length="20" />
</property>
<property name="password" type="java.lang.String">
<column name="PASSWORD" length="20" />
</property>
<component name="profile" class="com.crazy.Profile">
<parent name="user"/>
<property name="email" type="java.lang.String">
<column name="EMAIL" length="200" />
</property>
<property name="address" type="java.lang.String">
<column name="ADDRESS" length="200" />
</property>
<property name="postcode" type="java.lang.String">
<column name="POSTCODE" length="10" />
</property>
<property name="mobile" type="java.lang.String">
<column name="MOBILE" length="11" />
</property>
<property name="phone" type="java.lang.String">
<column name="PHONE" length="20" />
</property>
</component>
</class>
</hibernate-mapping>双向关联配置：
<parent name="user"/>
- 组件集合映射
使用组件集合映射，可以让组件对象的集合依附于一个持久化对象。
Product 类：
public class Product implements java.io.Serializable {
private Integer id;
private String name;
private Double price;
private String description;
private Date createTime;
private Set images = new HashSet();
public Product() {
}
public Product(String name, Double price, String description,
Date createTime, Set images) {
this.name = name;
this.price = price;
this.description = description;
this.createTime = createTime;
this.images = images;
}
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 Double getPrice() {
return this.price;
}
public void setPrice(Double price) {
this.price = price;
}
public String getDescription() {
return this.description;
}
public void setDescription(String description) {
this.description = description;
}
public Date getCreateTime() {
return this.createTime;
}
public void setCreateTime(Date createTime) {
this.createTime = createTime;
}
public Set getImages() {
return this.images;
}
public void setImages(Set images) {
this.images = images;
}
}Image 类：
public class Image {
private String fileName;
private String path;
private Integer imageSize;
public Image(){}
public Image(String fileName,String path, Integer imageSize){
this.fileName = fileName;
this.path = path;
this.imageSize = imageSize;
}
public String getFileName() {
return fileName;
}
public void setFileName(String fileName) {
this.fileName = fileName;
}
public String getPath() {
return path;
}
public void setPath(String path) {
this.path = path;
}
public Integer getImageSize() {
return imageSize;
}
public void setImageSize(Integer imageSize) {
this.imageSize = imageSize;
}
}映射配置文件：
<?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">
<!--
Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
<class name="com.crazy.Product" table="PRODUCT" schema="SCOTT">
<id name="id" type="java.lang.Integer">
<column name="ID" precision="8" scale="0" />
<generator class="increment" />
</id>
<property name="name" type="java.lang.String">
<column name="NAME" length="200" />
</property>
<property name="price" type="java.lang.Double">
<column name="PRICE" precision="6" />
</property>
<property name="description" type="java.lang.String">
<column name="DESCRIPTION" length="2000" />
</property>
<property name="createTime" type="java.util.Date">
<column name="CREATE_TIME" length="7" />
</property>
<set name="images" table="image">
<key column="PRODUCT_ID" foreign-key="id" />
<composite-element class="com.crazy.Image">
<property name="fileName" column="filename"></property>
<property name="path" column="path"></property>
<property name="imageSize" column="image_Size"></property>
</composite-element>
</set>
</class>
</hibernate-mapping>与Set映射比较相似，在第六章仅仅映射了一个字段，这里映射了一个组件。
<set name="images" table="image">
<key column="PRODUCT_ID" foreign-key="id" />
<composite-element class="com.crazy.Image">
<property name="fileName" column="filename"></property>
<property name="path" column="path"></property>
<property name="imageSize" column="image_Size"></property>
</composite-element>
</set>测试类：
public class HibernateTest {
public static void main(String[] args) {
HibernateTest test = new HibernateTest();
Product p = new Product();
p.setName("洗面奶");
p.setCreateTime(new Date());
p.setDescription("洗脸很干净！");
p.setPrice(999.99);
Set<Image> images = new HashSet();
images.add(new Image("filename1","filePath1",1000));
images.add(new Image("filename2","filePath2",2000));
images.add(new Image("filename3","filePath3",3000));
p.setImages(images);
test.addProduct(p);
}
public void addProduct(Product p){
Session session = new Configuration().configure().buildSessionFactory().openSession();
session.beginTransaction();
session.save(p);
session.getTransaction().commit();
}
public void printProduct(Product p){
System.out.println("商品编号：" + p.getId());
System.out.println("商品价格：" + p.getPrice());
System.out.println("商品名称：" + p.getName());
Set<Image> images = p.getImages();
for(Image image:images){
System.out.println("image名称：" + image.getFileName());
System.out.println("image路径：" + image.getPath());
System.out.println("image大小：" + image.getImageSize());
}
}
}