Java 无法使用Spring数据JPA创建联接
我是Spring数据新手，尝试通过以下教程和其他一些教程来解决这个问题，但没有太大成功 我试图在两个表之间使用Spring数据JPA进行简单的连接。 数据库中的表称为： *用户\车辆->包含每个用户所有车辆的信息，因为一个用户可以有许多车辆 *vehicle_model，包含有关车型id、名称等的数据 用户车辆表中数据库中的当前数据： ID |车辆ID |用户ID 1 | 1 | 1 2 | 2 | 1 下面是我尝试过但无法使用的代码，从帖子中删除getter和setter以缩短它：Java 无法使用Spring数据JPA创建联接,java,jpa,spring-data,Java,Jpa,Spring Data,我是Spring数据新手，尝试通过以下教程和其他一些教程来解决这个问题，但没有太大成功 我试图在两个表之间使用Spring数据JPA进行简单的连接。 数据库中的表称为： *用户\车辆->包含每个用户所有车辆的信息，因为一个用户可以有许多车辆 *vehicle_model，包含有关车型id、名称等的数据 用户车辆表中数据库中的当前数据： ID |车辆ID |用户ID 1 | 1 | 1 2 | 2 | 1 下面是我尝试过但无法使用的代码，从帖子中删除getter和setter以
@Entity(name = "vehicle_model")
public class VehicleModel {
@Id
@Min(1)
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private Long manufacturerId;
private String title;
private int ccm;
private int kw;
private int yearOfManufacture;
private int engineTypeId;
private boolean isActive;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "vehicle_id", insertable = false, updatable = false)
@Fetch(FetchMode.JOIN)
private UserVehicle userVehicle;
}
@Entity(name = "user_vehicle")
public class UserVehicle {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
@Column(nullable = false)
private long vehicleId;
@Column(nullable = false)
private long userId;
@OneToMany(targetEntity = VehicleModel.class, mappedBy = "userVehicle", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
List<VehicleModel> vehicleModels;
}
@Repository
public interface UserVehicleRepository extends CrudRepository<UserVehicle, Long>
{
Iterable<UserVehicle> findVehicleModelsByUserId(Long userId);
}
@Entity(name = "user")
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String username;
private String password;
private String firstName;
private String lastName;
private boolean isActive;
@OneToMany(mappedBy = "user")
private Set<UserVehicle> userVehicles;
@Entity(name = "user_vehicle")
public class UserVehicle {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
private boolean isActive;
@ManyToOne
@JoinColumn(name = "vehicle_id")
private Vehicle vehicle;
@ManyToOne
@JoinColumn(name = "user_id")
private User user;
@Entity(name = "vehicle_model")
public class Vehicle {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private Long manufacturerId;
private String title;
private int ccm;
private int kw;
private int yearOfManufacture;
private int engineTypeId;
private boolean isActive;
@OneToMany(mappedBy = "vehicle")
private Set<UserVehicle> userVehicles;
@Entity(name = "user")
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String username;
private String password;
private String firstName;
private String lastName;
private boolean isActive;
@OneToMany(mappedBy = "user")
private Set<UserVehicle> userVehicles;
@Entity(name = "user_vehicle")
public class UserVehicle {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
private boolean isActive;
@ManyToOne
@JoinColumn(name = "vehicle_id")
private Vehicle vehicle;
@ManyToOne
@JoinColumn(name = "user_id")
private User user;
@Entity(name = "vehicle_model")
public class Vehicle {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private Long manufacturerId;
private String title;
private int ccm;
private int kw;
private int yearOfManufacture;
private int engineTypeId;
private boolean isActive;
@OneToMany(mappedBy = "vehicle")
private Set<UserVehicle> userVehicles;
问题不是我真的不希望结果中包含用户对象，所以现在我需要弄清楚这一点。然后，我将尝试映射VehicleManufacturer类，以在相同的响应中获得这些结果。以下是我有意想要的解决方案-根据user\u vehicle表中的用户id搜索车辆：
@Entity(name = "user_vehicle")
public class UserVehicle {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
private boolean isActive;
private long userId;
@ManyToOne
@JoinColumn(name = "vehicle_id")
private Vehicle vehicle;
@Entity(name = "vehicle_model")
public class Vehicle {
@Id
@Min(1)
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private Long manufacturerId;
private String title;
private int ccm;
private int kw;
private int yearOfManufacture;
private int engineTypeId;
private boolean isActive;
@OneToMany(mappedBy = "vehicle")
private Set<UserVehicle> userVehicles;
@Repository
public interface UserVehicleRepository extends CrudRepository<UserVehicle, Long> {
Iterable<UserVehicle> findVehicleModelsByUserId(Long userId);
希望它能帮助某人以下是我有意想要的解决方案-根据用户车辆表中的用户id搜索车辆：
@Entity(name = "user_vehicle")
public class UserVehicle {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
private boolean isActive;
private long userId;
@ManyToOne
@JoinColumn(name = "vehicle_id")
private Vehicle vehicle;
@Entity(name = "vehicle_model")
public class Vehicle {
@Id
@Min(1)
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private Long manufacturerId;
private String title;
private int ccm;
private int kw;
private int yearOfManufacture;
private int engineTypeId;
private boolean isActive;
@OneToMany(mappedBy = "vehicle")
private Set<UserVehicle> userVehicles;
@Repository
public interface UserVehicleRepository extends CrudRepository<UserVehicle, Long> {
Iterable<UserVehicle> findVehicleModelsByUserId(Long userId);
希望它能帮助别人你确定你的onetomany映射是正确的吗？因为外键在用户\车辆表上。您确定您的onetomany映射正确吗？因为外键在用户\车辆表上。
@Entity(name = "user")
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String username;
private String password;
private String firstName;
private String lastName;
private boolean isActive;