JavaPersistenceWithHibernate第二版笔记-第七章-004Mapping a map(@MapKeyEnumerated 、 @MapKeyTemporal、@MapKeyColumn)

一、结构

二、代码

1.

 1 package org.jpwh.model.collections.mapofstrings;
 2
 3 import org.jpwh.model.Constants;
 4
 5 import javax.persistence.CollectionTable;
 6 import javax.persistence.Column;
 7 import javax.persistence.ElementCollection;
 8 import javax.persistence.Entity;
 9 import javax.persistence.GeneratedValue;
10 import javax.persistence.Id;
11 import javax.persistence.MapKeyColumn;
12 import java.util.HashMap;
13 import java.util.Map;
14
15 @Entity
16 public class Item {
17
18     @Id
19     @GeneratedValue(generator = Constants.ID_GENERATOR)
20     protected Long id;
21
22     @ElementCollection
23     @CollectionTable(name = "IMAGE")
24     @MapKeyColumn(name = "FILENAME")
25     @Column(name = "IMAGENAME")
26     protected Map<String, String> images = new HashMap<String, String>();
27
28     public Long getId() {
29         return id;
30     }
31
32     public Map<String, String> getImages() {
33         return images;
34     }
35
36     public void setImages(Map<String, String> images) {
37         this.images = images;
38     }
39
40     // ...
41 }

2.

 1 package org.jpwh.test.collections;
 2
 3 import org.jpwh.env.JPATest;
 4 import org.jpwh.model.collections.mapofstrings.Item;
 5 import org.testng.annotations.BeforeClass;
 6 import org.testng.annotations.Test;
 7
 8 import javax.persistence.EntityManager;
 9 import javax.transaction.UserTransaction;
10
11 import static org.testng.Assert.assertEquals;
12
13 public class MapOfStrings extends JPATest {
14
15     @Override
16     public void configurePersistenceUnit() throws Exception {
17         configurePersistenceUnit("MapOfStringsPU");
18     }
19
20     @Test
21     public void storeLoadCollection() throws Exception {
22         UserTransaction tx = TM.getUserTransaction();
23         try {
24             tx.begin();
25             EntityManager em = JPA.createEntityManager();
26             Item someItem = new Item();
27
28             someItem.getImages().put("foo.jpg", "Foo");
29             someItem.getImages().put("bar.jpg", "Bar");
30             someItem.getImages().put("baz.jpg", "WRONG!");
31             someItem.getImages().put("baz.jpg", "Baz");
32
33             em.persist(someItem);
34             tx.commit();
35             em.close();
36             Long ITEM_ID = someItem.getId();
37
38             tx.begin();
39             em = JPA.createEntityManager();
40             Item item = em.find(Item.class, ITEM_ID);
41             assertEquals(item.getImages().size(), 3);
42             assertEquals(item.getImages().get("foo.jpg"), "Foo");
43             assertEquals(item.getImages().get("bar.jpg"), "Bar");
44             assertEquals(item.getImages().get("baz.jpg"), "Baz");
45             tx.commit();
46             em.close();
47         } finally {
48             TM.rollback();
49         }
50     }
51
52 }

3.

1     <persistence-unit name="MapOfStringsPU">
2         <jta-data-source>myDS</jta-data-source>
3         <class>org.jpwh.model</class>
4         <class>org.jpwh.model.collections.mapofstrings.Item</class>
5         <exclude-unlisted-classes>true</exclude-unlisted-classes>
6     </persistence-unit>