Hibernate4自學入門（九）——映射繼承

一、每個具體類對應一個表

model

public class Student {
	
	private int id;
	
	private String name;
	
	private Set<Image> images;

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Set<Image> getImages() {
		return images;
	}

	public void setImages(Set<Image> images) {
		this.images = images;
	}
	

}

一個抽象的父類

public abstract class Image {
	private int id;
	private String imageName;
	private Student student;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getImageName() {
		return imageName;
	}
	public void setImageName(String imageName) {
		this.imageName = imageName;
	}
	public Student getStudent() {
		return student;
	}
	public void setStudent(Student student) {
		this.student = student;
	}
	
	
	
	
	
}

多個繼承上述抽象父類的子類：

public class LifeImage extends Image {

	
	
}

每個實體類對應一個表 即：student、workImage、LifeImage各生成一張表

<hibernate-mapping package="com.gw.model">

	<class name="WorkImage" table="t_workImage">
		<id name="id" column="workImageId">
			<generator class="native"></generator>
		</id>
		
		<property name="imageName" column="imageName"></property>
		
		<many-to-one name="student" column="stuId" class="com.gw.model.Student"></many-to-one>
		
	</class>

</hibernate-mapping>

LifeImage同上、Student即標準寫法。

test:

	@Test
	public void test() throws IOException, ParseException {
		List<Image> imageList = new ArrayList<Image>();
		int stuId=1;
		List<Image> lifeImageList =(List<Image>)session.createQuery("from LifeImage l where l.student.id="+stuId).list();
		imageList.addAll(lifeImageList);
		List<Image> workImageList =(List<Image>)session.createQuery("from WorkImage w where w.student.id="+stuId).list();
		imageList.addAll(workImageList);
		Iterator it=imageList.iterator();
		
		while(it.hasNext()){
			
			Image image =(Image)it.next();
			System.out.println(image.getImageName())	;
			
			
		}
		
		
	}

二、根類對應一個表

student 不變。

根類Image:

public  class Image2 {
	private int id;
	private String imageName;
	private Student2 student;
	private String imageType;
	
	public String getImageType() {
		return imageType;
	}
	public void setImageType(String imageType) {
		this.imageType = imageType;
	}
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getImageName() {
		return imageName;
	}
	public void setImageName(String imageName) {
		this.imageName = imageName;
	}
	public Student2 getStudent() {
		return student;
	}
	public void setStudent(Student2 student) {
		this.student = student;
	}

	
	
	
	
	
}

概念：imageType 用來給表裏的信息進行分類提取——對應下述的discriminator。

根類對應的表：

<hibernate-mapping package="com.gw.model">

	<class name="Image2" table="t_image2">
		<id name="id" column="imageId">
			<generator class="native"></generator>
		</id>
		<discriminator column="imageType" type="string"></discriminator>
		<property name="imageName" column="imageName"></property>
		
		<many-to-one name="student" column="stuId" class="com.gw.model.Student2"></many-to-one>
		
		<subclass name="com.gw.model.LifeImage2" discriminator-value="li"></subclass>
		<subclass name="com.gw.model.WorkImage2" discriminator-value="wo"></subclass>
	</class>

</hibernate-mapping>

Student對應的表

<hibernate-mapping package="com.gw.model">

	<class name="Student2" table="t_student2">
		<id name="id" column="stuId">
			<generator class="native"></generator>
		</id>
		
		<property name="name" column="stuName"></property>
		<set name="images">
			<key column="stuId"></key>
			<one-to-many class="com.gw.model.Image2"/> 
		</set>
	</class>

</hibernate-mapping>

test:

	@Test
	public void test2() throws IOException, ParseException {
		Student2  student2 = (Student2) session.get(Student2.class, 1);		
		
		Set<Image2> images=student2.getImages();
		
		
	Iterator it=images.iterator();
		
		while(it.hasNext()){
			
			Image2 image =(Image2)it.next();
			System.out.println(image.getImageName())	;
			
			
		}
		
		
	} 

三、每個類對應一個表

image根類和Student model類不變 兩個子類不變

Student對應的表：

<hibernate-mapping package="com.gw.model">

	<class name="Student3" table="t_student3">
		<id name="id" column="stuId">
			<generator class="native"></generator>
		</id>
		
		<property name="name" column="stuName"></property>
		<set name="images">
			<key column="stuId"></key>
			<one-to-many class="com.gw.model.Image3"/> 
		</set>
	</class>

</hibernate-mapping>

Image對應的表：

<hibernate-mapping package="com.gw.model">

	<class name="Image3" table="t_image3">
		<id name="id" column="imageId">
			<generator class="native"></generator>
		</id>
		<property name="imageName" column="imageName"></property>
		
		<many-to-one name="student" column="stuId" class="com.gw.model.Student3"></many-to-one>
		
		<joined-subclass name="com.gw.model.LifeImage3" table="t_lifeImage3">
			<key column="lifeImageId"></key>
		</joined-subclass>
		
		<joined-subclass name="com.gw.model.WorkImage3" table="t_workImage3">
			<key column="workImageId"></key>
		</joined-subclass>
	</class>

</hibernate-mapping>