not-null 属性引用空值或瞬态值 [英] not-null property references a null or transient value

问题描述

在使用休眠保存父/子对象时遇到问题.任何想法将不胜感激.

Facing trouble in saving parent/child object with hibernate. Any idea would be highly appreciated.

org.hibernate.PropertyValueException: not-null property references a null or transient value: example.forms.InvoiceItem.invoice
    at org.hibernate.engine.Nullability.checkNullability(Nullability.java:100)
        .... (truncated)

休眠映射:

<hibernate-mapping package="example.forms">
    <class name="Invoice" table="Invoices">
        <id name="id" type="long">
            <generator class="native" />
        </id>
        <property name="invDate" type="timestamp" />
        <property name="customerId" type="int" />
        <set cascade="all" inverse="true" lazy="true" name="items" order-by="id">
            <key column="invoiceId" />
            <one-to-many class="InvoiceItem" />
        </set>
    </class>
    <class name="InvoiceItem" table="InvoiceItems">
        <id column="id" name="itemId" type="long">
            <generator class="native" />
        </id>
        <property name="productId" type="long" />
        <property name="packname" type="string" />
        <property name="quantity" type="int" />
        <property name="price" type="double" />
        <many-to-one class="example.forms.Invoice" column="invoiceId" name="invoice" not-null="true" />
    </class>
</hibernate-mapping>

发票管理器.java

class InvoiceManager {

    public Long save(Invoice theInvoice) throws RemoteException {
        Session session = HbmUtils.getSessionFactory().getCurrentSession();
        Transaction tx = null;
        Long id = null;
        try {
            tx = session.beginTransaction();
            session.persist(theInvoice);
            tx.commit();
            id = theInvoice.getId();
        } catch (RuntimeException e) {
            if (tx != null)
                tx.rollback();
            e.printStackTrace();
            throw new RemoteException("Invoice could not be saved");
        } finally {
            if (session.isOpen())
                session.close();
        }
        return id;
    }
}

发票.java

public class Invoice implements java.io.Serializable {
    private Long id;
    private Date invDate;
    private int customerId;
    private Set<InvoiceItem> items;

    public Long getId() {
        return id;
    }
    public Date getInvDate() {
        return invDate;
    }
    public int getCustomerId() {
        return customerId;
    }
    public Set<InvoiceItem> getItems() {
        return items;
    }
    void setId(Long id) {
        this.id = id;
    }
    void setInvDate(Date invDate) {
        this.invDate = invDate;
    }
    void setCustomerId(int customerId) {
        this.customerId = customerId;
    }
    void setItems(Set<InvoiceItem> items) {
        this.items = items;
    }
}

InvoiceItem.java

InvoiceItem.java

public class InvoiceItem implements java.io.Serializable {
    private Long itemId;
    private long productId;
    private String packname;
    private int quantity;
    private double price;
    private Invoice invoice;

    public Long getItemId() {
        return itemId;
    }
    public long getProductId() {
        return productId;
    }
    public String getPackname() {
        return packname;
    }
    public int getQuantity() {
        return quantity;
    }
    public double getPrice() {
        return price;
    }
    public Invoice getInvoice() {
        return invoice;
    }
    void setItemId(Long itemId) {
        this.itemId = itemId;
    }
    void setProductId(long productId) {
        this.productId = productId;
    }
    void setPackname(String packname) {
        this.packname = packname;
    }
    void setQuantity(int quantity) {
        this.quantity = quantity;
    }
    void setPrice(double price) {
        this.price = price;
    }
    void setInvoice(Invoice invoice) {
        this.invoice = invoice;
    }
}

推荐答案

每个 InvoiceItem 都必须附加一个 Invoice 因为 not-null=多对一映射中的true".

Every InvoiceItem must have an Invoice attached to it because of the not-null="true" in the many-to-one mapping.

所以基本的想法是你需要在代码中建立明确的关系.有很多方法可以做到这一点.在你的课上，我看到了一个 setItems 方法.我没有看到 addInvoiceItem 方法.当您设置项目时，您需要遍历集合并对所有项目调用 item.setInvoice(this).如果你实现一个 addItem 方法，你需要做同样的事情.或者您需要另外设置集合中每个 InvoiceItem 的 Invoice.

So the basic idea is you need to set up that explicit relationship in code. There are many ways to do that. On your class I see a setItems method. I do NOT see an addInvoiceItem method. When you set items, you need to loop through the set and call item.setInvoice(this) on all of the items. If you implement an addItem method, you need to do the same thing. Or you need to otherwise set the Invoice of every InvoiceItem in the collection.

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