我在使用 Hibernate 和oneToMany映射时遇到了一些问题。
这是我的功能：
Location location = new Location();
location.setDateTime(new Date());
location.setLatitude(lat);
location.setLongitude(lon);
location = this.locationDao.save(location);
merchant = new Merchant();
merchant.setAddress(address);
merchant.setCity(city);
merchant.setCountry(country);
merchant.setLocation(location);
merchant.setName(name);
merchant.setOrganization(organization);
merchant.setPublicId(publicId);
merchant.setZipCode(zipCode);
merchant.setApplication(this.applicationDAO.findByPublicId(applicationPublicId));
merchant = this.merchantDao.save(merchant);
return merchant;
这是我的两个实体：
地点
import java.io.Serializable;
import java.util.Date;
import java.util.List;
import javax.persistence.*;
import javax.validation.constraints.NotNull;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlTransient;
@Entity
@Table(name = "location")
@XmlRootElement
public class Location implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "id", nullable = false)
private Long id;
@Basic(optional = false)
@NotNull
@Column(name = "latitude", nullable = false)
private double latitude;
@Basic(optional = false)
@NotNull
@Column(name = "longitude", nullable = false)
private double longitude;
@Basic(optional = false)
@NotNull
@Column(name = "date_time", nullable = false)
@Temporal(TemporalType.TIMESTAMP)
private Date dateTime;
@OneToMany(cascade = CascadeType.ALL, mappedBy = "location")
private List<Merchant> retailerList;
@OneToMany(cascade = CascadeType.ALL, mappedBy = "location")
private List<MobileUser> userList;
public Location() {
}
public Location(Long id) {
this.id = id;
}
public Location(Long id, double latitude, double longitude, Date dateTime) {
this.id = id;
this.latitude = latitude;
this.longitude = longitude;
this.dateTime = dateTime;
}
public Long getId() {
return id;
}
//getters and setters
@XmlTransient
public List<Merchant> getRetailerList() {
return retailerList;
}
public void setRetailerList(List<Merchant> retailerList) {
this.retailerList = retailerList;
}
@XmlTransient
public List<MobileUser> getUserList() {
return userList;
}
public void setUserList(List<MobileUser> userList) {
this.userList = userList;
}
@Override
public int hashCode() {
int hash = 0;
hash += (id != null ? id.hashCode() : 0);
return hash;
}
@Override
public boolean equals(Object object) {
// TODO: Warning - this method won't work in the case the id fields are not set
if (!(object instanceof Location)) {
return false;
}
Location other = (Location) object;
if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
return false;
}
return true;
}
@Override
public String toString() {
return "com.fgsecure.geoloc.entities.Location[ id=" + id + " ]";
}
商人
import java.io.Serializable;
import javax.persistence.*;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import javax.xml.bind.annotation.XmlRootElement;
import org.codehaus.jackson.annotate.JsonAutoDetect;
import org.codehaus.jackson.annotate.JsonIgnore;
@JsonAutoDetect
@Entity
@Table(name = "retailer")
@XmlRootElement
public class Merchant implements Serializable {
private static final long serialVersionUID = 1L;
@JsonIgnore
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "id", nullable = false)
private Long id;
@Basic(optional = false)
@NotNull
@Size(min = 1, max = 50)
@Column(name = "public_id", nullable = false, length = 50)
private String publicId;
@Basic(optional = false)
@NotNull
@Size(min = 1, max = 50)
@Column(name = "name", nullable = false, length = 50)
private String name;
@Size(max = 50)
@Column(name = "organization", length = 50)
private String organization;
@Size(max = 128)
@Column(name = "address", length = 128)
private String address;
@Size(max = 10)
@Column(name = "zip_code", length = 10)
private String zipCode;
@Size(max = 50)
@Column(name = "city", length = 50)
private String city;
@Size(max = 50)
@Column(name = "country", length = 50)
private String country;
@JoinColumn(name = "location_id", referencedColumnName = "id", nullable = false)
@ManyToOne(optional = false)
private Location location;
@JoinColumn(name = "application_id", referencedColumnName = "id", nullable = false)
@ManyToOne(optional = false)
private Application application;
public Merchant() {
}
public Merchant(Long id) {
this.id = id;
}
public Merchant(Long id, String publicId, String name) {
this.id = id;
this.publicId = publicId;
this.name = name;
}
//getters and setters
@Override
public int hashCode() {
int hash = 0;
hash += (id != null ? id.hashCode() : 0);
return hash;
}
@Override
public boolean equals(Object object) {
// TODO: Warning - this method won't work in the case the id fields are not set
if (!(object instanceof Merchant)) {
return false;
}
Merchant other = (Merchant) object;
if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
return false;
}
return true;
}
@Override
public String toString() {
return "com.fgsecure.geoloc.entities.Retailer[ id=" + id + " ]";
}
}
每次我调用我的函数时，我都会得到：
org.hibernate.id.IdentifierGenerationException: ids for this class must be manually assigned before calling save():
对于这一行：
location = this.locationDao.save(location);
我不明白为什么。因为在这种情况下，无需手动分配位置 id，因为它是自动生成的。我一定是做错了什么，但 3 天后我没有找到。
我正在使用 PostGreSQL，并且 id 是具有以下序列的自动生成的 ID：
nextval('location_id_seq'::regclass)`
编辑解决：
好的，谢谢您的回答。
如果将来可以帮助其他人，只需通过以下方式修改 id 的参数：
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "id",unique=true, nullable = false)