Question

我得到以下代码：

Car.java：

    package org.tjatte;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;
import javax.persistence.Table;

@Entity
@Table(name = "Car")
public class Car {

    @Id
    @Column(name = "Car_ID", nullable = false)
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int carId;

    @Column(name = "Car_DESIGNATION", nullable = false)
    private String designation;

    @ManyToOne
    @JoinColumn(name = "GARAGE_ID")
    public Garage carGarage;


    public Car(String bez) {
        this.designation = bez;
    }

    public int getCarId() {
        return carId;
    }

    public void setCarId(int carId) {
        this.carId = carId;
    }

    public String getDesignation() {
        return designation;
    }

    public void setDesignation(String designation) {
        this.designation = designation;
    }

    public Garage getCarGarage() {
        return carGarage;
    }

    public void setCarGarage(Garage carGarage) {
        this.carGarage = carGarage;
    }

    public void print() {
        System.out.println("Designation: " + getDesignation());
    }
}

Garage.java

    package org.tjatte;
import java.util.ArrayList;
import java.util.List;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;

@Entity
@Table(name = "Garage")
public class Garage {

    @Id
    @Column(name = "Garage_ID", nullable = false)
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int garageId;

    @Column(name = "Garage_DESIGNATION", nullable = false)
    private String designation;

    @OneToMany(mappedBy = "carGarage", cascade = CascadeType.ALL)
    @Column(name = "GARAGE_ID")
    public List<Car> carsInGarage = new ArrayList<Car>();

    public Garage(String bez) {
        this.designation = bez;
    }

    public int getGarageId() {
        return garageId;
    }

    public void setGarageId(int garageId) {
        this.garageId = garageId;
    }

    public String getDesignation() {
        return designation;
    }

    public void setDesignation(String designation) {
        this.designation = designation;
    }

    public List<Car> getCarsInGarage() {
        return carsInGarage;
    }

    public void setCarsInGarage(List<Car> carsInGarage) {
        this.carsInGarage = carsInGarage;
    }

    public void print() {
        for(Car c : carsInGarage) {
            c.print();
        }
    }

}

MainTest.java

    package org.tjatte;
import java.util.Arrays;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;

public class MainTest {

    public static void main(String[] args) {
        SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
        Session session = sessionFactory.openSession();
        Transaction tx = session.beginTransaction();

        Garage garage = new Garage("Big");
        Car oneCar = new Car("Opel");
        Car anotherCar = new Car("Mercedes");
        garage.setCarsInGarage(Arrays.asList(oneCar, anotherCar));
        session.save(garage);
        tx.commit();

    }

}

我正在尝试实现Car和Garage之间的OneToMany映射，并且通常不会出现任何错误。但是最终结果不是我所期望的。

结果如下：

但是我希望这样：

（图片中的数字1是已插入表Garage中的车库的ID。这就是确切的车库，我已在MainTest中添加了汽车）

我非常感谢您的帮助！花一些时间在上面，但是我看不到为什么我在那一栏上没有输入空值。

谢谢。

Hibernate OneToMany映射失败

0 个答案: