配置聚合映射

接下来我们为新实体创建映射：

package com.lugew.springbootddd;
import lombok.Getter;
import lombok.Setter;
import javax.persistence.Entity;
import javax.persistence.Id;
@Entity
@Setter
@Getter
public class SnackDto {
    @Id
    private long id;
    private String name;
    public Snack convertToSnack() {
        if (id == 0) return Snack.None;
        else if (id == 1) return Snack.Chocolate;
        else if (id == 2) return Snack.Soda;
        else return Snack.Gum;
    }
}

SnackDto类很简单，只包含id和name，SlotDto则复杂一些：

package com.lugew.springbootddd;
import lombok.Getter;
import lombok.Setter;
import javax.persistence.Entity;
import javax.persistence.*;
@Entity
@Getter
@Setter
public class SlotDto {
    @Id
    @GeneratedValue
    private long id;
    private int quantity;
    private float price;
    @OneToOne(cascade = CascadeType.ALL)
    private SnackDto snackDto;
    private int position;
    public Slot convertToSlot() {
        Slot slot = new Slot();
        slot.setId(id);
        slot.setPosition(position);
        slot.setSnackPile(new SnackPile(snackDto.convertToSnack(), quantity, price));
        return slot;
    }
}

package com.lugew.springbootddd;
import com.lugew.springbootddd.snackmachine.Money;
import com.lugew.springbootddd.snackmachine.SnackMachine;
import lombok.Getter;
import lombok.Setter;
import javax.persistence.Entity;
import javax.persistence.*;
import java.util.ArrayList;
import java.util.List;
/**
 * @author 夏露桂
 * @since 2021/6/10 12:00
 */
@Getter
@Setter
@Entity
public class SnackMachineDto {
    @Id
    @GeneratedValue
    private long id;
    private int oneCentCount;
    private int tenCentCount;
    private int quarterCount;
    private int oneDollarCount;
    private int fiveDollarCount;
    private int twentyDollarCount;
    private float moneyInTransaction;
    @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
    @JoinColumn(name = "snackMachineId")
    private List<SlotDto> slotDtoList;
    public SnackMachine convertToSnackMachine() {
        SnackMachine snackMachine = new SnackMachine();
        snackMachine.setId(id);
        snackMachine.setMoneyInTransaction(moneyInTransaction);
        snackMachine.setMoneyInside(new
                Money(oneCentCount, tenCentCount, quarterCount,
                oneDollarCount, fiveDollarCount, twentyDollarCount));
        List<Slot> slotList = new ArrayList<>();
        for (SlotDto slotDto : slotDtoList) {
            slotList.add(slotDto.convertToSlot());
        }
        snackMachine.setSlots(slotList);
        return snackMachine;
    }
}

重启系统后，Springboot会自动创建数据库表。