hibernate annotation 之 多对一单向外键关联
假设，一个农场产出多种植物，具体的某一植物产于某一农场。
1 package net.yeah.fancydeepin.po;
2
3 import java.io.Serializable;
4 import javax.persistence.Column;
5 import javax.persistence.Entity;
6 import javax.persistence.GeneratedValue;
7 import javax.persistence.Id;
8 /**
9 * -----------------------------------------
10 * @描述 农场
11 * @作者 fancy
12 * @邮箱 fancydeepin@yeah.net
13 * @日期 2012-10-21 <p>
14 * -----------------------------------------
15 */
16 @Entity
17 public class Farm implements Serializable{
18
19 private static final long serialVersionUID = 1L;
20
21 private Integer id;
22 private String name;
23
24 @Id
25 @GeneratedValue
26 public Integer getId() {
27 return id;
28 }
29 @Column(length = 18, nullable = false)
30 public String getName() {
31 return name;
32 }
33 public void setId(Integer id) {
34 this.id = id;
35 }
36 public void setName(String name) {
37 this.name = name;
38 }
39 }
1 package net.yeah.fancydeepin.po;
2
3 import java.io.Serializable;
4 import javax.persistence.CascadeType;
5 import javax.persistence.Column;
6 import javax.persistence.Entity;
7 import javax.persistence.FetchType;
8 import javax.persistence.GeneratedValue;
9 import javax.persistence.Id;
10 import javax.persistence.ManyToOne;
11 /**
12 * -----------------------------------------
13 * @描述 植物
14 * @作者 fancy
15 * @邮箱 fancydeepin@yeah.net
16 * @日期 2012-10-21 <p>
17 * -----------------------------------------
18 */
19 @Entity
20 public class Plant implements Serializable{
21
22 private static final long serialVersionUID = 1L;
23
24 private Integer id;
25 private String name;
26 private Farm farm;
27
28 @Id
29 @GeneratedValue
30 public Integer getId() {
31 return id;
32 }
33 @Column(length = 18, nullable = false)
34 public String getName() {
35 return name;
36 }
37 @ManyToOne(cascade = CascadeType.PERSIST, optional = false, fetch = FetchType.LAZY)
38 public Farm getFarm() {
39 return farm;
40 }
41 public void setId(Integer id) {
42 this.id = id;
43 }
44 public void setName(String name) {
45 this.name = name;
46 }
47 public void setFarm(Farm farm) {
48 this.farm = farm;
49 }
50
51 }
Junit 测试 :
1 @Test
2 public void createTable(){
3
4 new SchemaExport(new AnnotationConfiguration().configure()).create(true, true);
5 }
执行上面的单元测试，数据库中生成的表的结构图 :
级联保存 :
1 private static Session session;
2
3 @BeforeClass
4 public static void beforeClass(){
5
6 session = new AnnotationConfiguration().configure().buildSessionFactory().getCurrentSession();
7 }
8
9 @Test
10 public void insert(){
11 try {
12 Farm farm = new Farm();
13 farm.setName("fancy-farm");
14 Plant tomato = new Plant();
15 tomato.setName("番茄");
16 tomato.setFarm(farm);
17 Plant cabbage = new Plant();
18 cabbage.setName("卷心菜");
19 cabbage.setFarm(farm);
20 session.beginTransaction();
21 session.persist(tomato);
22 session.persist(cabbage);
23 session.getTransaction().commit();
24 } catch (Exception e) {
25 e.printStackTrace();
26 }
27 }
补充：软件开发 , Java ,
