JPA 注解 OneToMany和ManyToOne

本例涉及的表（ym_user)一的一方，表（ym_sub_user）多的一方，在写代码时，需要建立表，并建立ym_sub_user中设置外键关联ym_user。表的字段如下：
ym_user(id,name)
ym_sub_user(id,user_id,subname)

@Entity
@Table(name = "YM_USER")
public class User {

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private int id;

@Column(name = "name")
private String name;

@OneToMany(mappedBy="user",fetch=FetchType.EAGER)
private Set<SubName> subNameList = new HashSet<SubName>();

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<SubName> getSubNameList() {
return subNameList;
}

public void setSubNameList(Set<SubName> subNameList) {
this.subNameList = subNameList;
}

}

@Entity
@Table(name = "ym_sub_user")
public class SubName {
@Id
private int id;

@Column(name = "sub_name")
private String subName;

@ManyToOne(targetEntity = User.class)
@JoinColumn(name="user_id")
private User user;

public int getId() {
return id;
}

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

public String getSubName() {
return subName;
}

public void setSubName(String subName) {
this.subName = subName;
}

}