Hibernate学习6—Hibernate 映射类型

第一节：基本类型映射　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　

com.cy.model.Book.java:

package com.cy.model;

import java.sql.Blob;
import java.util.Date;

public class Book {
    private int id;
    private String bookName; // 图书名称
    private float price; //图书价格
    private boolean specialPrice; //是否是特价
    private Date publishDate; // 发布日期
    private String author; // 作者
    private String introduction; // 简介
    private Blob bookPic; // 图书图片
    
    
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getBookName() {
        return bookName;
    }
    public void setBookName(String bookName) {
        this.bookName = bookName;
    }
    public float getPrice() {
        return price;
    }
    public void setPrice(float price) {
        this.price = price;
    }
    public boolean isSpecialPrice() {
        return specialPrice;
    }
    public void setSpecialPrice(boolean specialPrice) {
        this.specialPrice = specialPrice;
    }
    public Date getPublishDate() {
        return publishDate;
    }
    public void setPublishDate(Date publishDate) {
        this.publishDate = publishDate;
    }
    public String getAuthor() {
        return author;
    }
    public void setAuthor(String author) {
        this.author = author;
    }
    public String getIntroduction() {
        return introduction;
    }
    public void setIntroduction(String introduction) {
        this.introduction = introduction;
    }
    public Blob getBookPic() {
        return bookPic;
    }
    public void setBookPic(Blob bookPic) {
        this.bookPic = bookPic;
    }
    
    
}

Book.hbm.xml:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.cy.model">
    <class name="Book" table="t_book">
        <id name="id" column="bookId">
            <generator class="native"></generator>
        </id>
        <!-- 
            type是对应的hibernate映射类型
            length=“40”表示字符串长度为40
         -->
        <property name="bookName" column="bookName" length="40"></property>
        <property name="price" column="price" type="float"></property>
        <property name="specialPrice" column="specialPrice" type="boolean"></property>
        <property name="publishDate" column="publishDate" type="date"></property>
        <property name="author" column="author" length="20"></property>
        <property name="introduction" column="introduction" type="text"></property>
        <property name="bookPic" column="bookPic" type="blob"></property>
    </class>
</hibernate-mapping>

BookTest.java测试代码：

public class BookTest {
    public static void main(String[] args) throws ParseException, IOException {
        SessionFactory sessionFactory = HibernateUtil.getSessionFactory();
        Session session = sessionFactory.openSession();    
        session.beginTransaction();    
        
        Book book = new Book();
        book.setBookName("java编程思想");
        book.setPrice(100);
        book.setSpecialPrice(true);
        book.setAuthor("埃克尔");
        book.setPublishDate(new SimpleDateFormat("yyyy-MM-dd").parse("2017-1-1"));
        book.setIntroduction("简介...");
        
        LobHelper lobHelper = session.getLobHelper();
        InputStream in = new FileInputStream("c://java编程思想.jpg");
        Blob bookPic = lobHelper.createBlob(in, in.available());
        book.setBookPic(bookPic);
        
        session.save(book);
        
        session.getTransaction().commit();    
        session.close();    
    }
    
}

结果：

t_book:

存数据后：

第二节：集合类型映射　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　

这里讲的集合和前面一对多多对一的集合不一样；

这里是一种组合；单纯的数据映射，不带session缓存的，也不包括OID

 

1.Set集合映射：

Student.java:

package com.cy.model;

import java.util.Set;

public class Student {
    private long id;
    private String name;
    private Set<String> images;
    
    public long getId() {
        return id;
    }
    public void setId(long id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Set<String> getImages() {
        return images;
    }
    public void setImages(Set<String> images) {
        this.images = images;
    }
    
}

Student.hbm.xml:

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

    <class name="Student" table="t_student">
        <id name="id" column="stuId">
            <generator class="native"></generator>
        </id>
        
        <property name="name" column="stuName"></property>
        
        <!-- t_image表的外键studentId关联Student表的主键
             element元素是集合的元素
         -->
        <set name="images" table="t_image">
            <key column="studentId"></key>
            <element column="imageName" type="string"></element>
        </set>
    </class>

</hibernate-mapping>

测试：

@Test
    public void testSetSave(){
        Set<String> imageSet=new HashSet<String>();
        imageSet.add("image1.png");
        imageSet.add("image2.png");
        imageSet.add("image3.png");
        imageSet.add("image3.png");
        
        Student s1=new Student();
        s1.setImages(imageSet);
        session.save(s1);
    }
    
    @Test
    public void testSetFetch(){
        Student student=(Student)session.get(Student.class, Long.valueOf(1));
        Iterator it = student.getImages().iterator();
        while(it.hasNext()){
            System.out.println(it.next());
        }
    }

执行testSetSave后：

t_student

t_image：外键studentId 参考t_student的主键列

2.List集合映射：

List：正是因为有了索引列imageIndex，所以他才是有序的；

Student2.java：

package com.cy.model;

import java.util.List;

public class Student2 {
    private long id;
    private String name;
    private List<String> images;
    
    public long getId() {
        return id;
    }
    public void setId(long id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public List<String> getImages() {
        return images;
    }
    public void setImages(List<String> images) {
        this.images = images;
    }
    
}

Student2.hbm.xml:

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

    <class name="Student2" table="t_student">
        <id name="id" column="stuId">
            <generator class="native"></generator>
        </id>
        <property name="name" column="stuName"></property>
        
        <list name="images" table="t_image2">
            <key column="studentId"></key>
            <list-index column="imageIndex"></list-index>
            <element column="imageName" type="string"></element>
        </list>
    </class>

</hibernate-mapping>

测试代码：

@Test
    public void testListSave(){
        List<String> imageList=new ArrayList<String>();
        imageList.add("image1.png");
        imageList.add("image2.png");
        imageList.add("image3.png");
        imageList.add("image3.png");
        
        Student2 s2=new Student2();
        s2.setImages(imageList);
        session.save(s2);
    }
    
    @Test
    public void testListFetch(){
        Student2 student2=(Student2)session.get(Student2.class, Long.valueOf(2));
        Iterator it = student2.getImages().iterator();
        while(it.hasNext()){
            System.out.println(it.next());
        }
    }

t_student：

t_image2：

3.Bag集合映射：

用List来模拟的；大多数情况下是有序的；但是数据量很大时，确实是无序。

student3.java:

package com.cy.model;

import java.util.List;

public class Student3 {
    private long id;
    private String name;
    private List<String> images;
    
    public long getId() {
        return id;
    }
    public void setId(long id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public List<String> getImages() {
        return images;
    }
    public void setImages(List<String> images) {
        this.images = images;
    }
    
}

Student3.hbm.xml:

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

    <class name="Student3" table="t_student">
        <id name="id" column="stuId">
            <generator class="native"></generator>
        </id>
        <property name="name" column="stuName"></property>
        
        <idbag name="images" table="t_image3">
            <collection-id type="long" column="imageId">
                <generator class="increment"></generator>
            </collection-id>
            <key column="studentId"></key>
            <element column="imageName" type="string"></element>
        </idbag>
    </class>

</hibernate-mapping>

测试代码：

@Test
    public void testBagSave(){
        List<String> imageList=new ArrayList<String>();
        imageList.add("image1.png");
        imageList.add("image2.png");
        imageList.add("image3.png");
        imageList.add("image3.png");
        
        Student3 s3=new Student3();
        s3.setImages(imageList);
        session.save(s3);
    }
    
    @Test
    public void testBagFetch(){
        Student3 student3 =(Student3)session.get(Student3.class, Long.valueOf(3));
        Iterator it = student3.getImages().iterator();
        while(it.hasNext()){
            System.out.println(it.next());
        }
    }

4.Map集合映射   

Student4.java:

package com.cy.model;

import java.util.Map;


public class Student4 {
    private long id;
    private String name;
    private Map<String, String> images;
    
    public long getId() {
        return id;
    }
    public void setId(long id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Map<String, String> getImages() {
        return images;
    }
    public void setImages(Map<String, String> images) {
        this.images = images;
    }
    
    
}

Student4.hbm.xml:

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

    <class name="Student4" table="t_student">
        <id name="id" column="stuId">
            <generator class="native"></generator>
        </id>
        <property name="name" column="stuName"></property>
        
        <map name="images" table="t_image4">
            <key column="studentId"></key>
            <map-key column="imageKey" type="string"></map-key>
            <element column="imageName" type="string"></element>
        </map>
    </class>

</hibernate-mapping>

测试代码：

@Test
    public void testMapSave(){
        Map<String, String> imageMap = new HashMap<String, String>();
        imageMap.put("i1", "image1.png");
        imageMap.put("i2", "image2.png");
        imageMap.put("i3", "image3.png");
        imageMap.put("i4", "image4.png");
        
        Student4 s4=new Student4();
        s4.setImages(imageMap);
        session.save(s4);
    }
    
    @Test
    public void testMapFetch(){
        Student4 student4 =(Student4)session.get(Student4.class, Long.valueOf(4));
        /**
         * 遍历map，方法一
         */
        Iterator<Entry<String, String>>  it = student4.getImages().entrySet().iterator();
        while(it.hasNext()){
            Entry<String, String> entry = it.next();
            System.out.println(entry.getKey() + "----" + entry.getValue());
        }
        
        System.out.println("------------------------------------------------");
        
        /**
         * 方法二
         */
        Map<String, String> imageMap = student4.getImages();
        Set<String> imageKey = imageMap.keySet();
        Iterator<String> its = imageKey.iterator();
        while(its.hasNext()){
            String key = its.next();
            System.out.println(key + ":" + imageMap.get(key));
        }
    }

执行testMapSave：

t_image4表结构：

执行testMapFetch：