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。
3 import java.io.Serializable;
4 import java.util.Set;
5 import javax.persistence.CascadeType;
6 import javax.persistence.Column;
7 import javax.persistence.Entity;
8 import javax.persistence.FetchType;
9 import javax.persistence.GeneratedValue;
10 import javax.persistence.Id;
11 import javax.persistence.OneToMany;
12 /**
13 * -----------------------------------------
14 * @描述 农场
17 * @日期 2012-10-21 <p>
18 * -----------------------------------------
19 */
20 @Entity
21 public class Farm implements Serializable{
22
23 private static final long serialVersionUID = 1L;
24
25 private Integer id;
26 private String name;
27 private Set<Plant> plantSet;
28
29 @Id
30 @GeneratedValue
31 public Integer getId() {
32 return id;
33 }
34 @Column(length = 18, nullable = false)
35 public String getName() {
36 return name;
37 }
38 @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "farm")
39 public Set<Plant> getPlantSet() {
40 return plantSet;
41 }
42 public void setId(Integer id) {
43 this.id = id;
44 }
45 public void setName(String name) {
46 this.name = name;
47 }
48 public void setPlantSet(Set<Plant> plantSet) {
49 this.plantSet = plantSet;
50 }
51 }
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
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 }