java - Hibernate一对多映射配置

Question

我是 hibernate 新手，我正在尝试通过级联加载和更新来实现一对多关系。但是，我的代码总是生成 org.apache.jasper.JasperException: org.hibernate.MappingException: Could not get constructor for org.hibernate.persister.entity.SingleTableEntityPersister 异常。你能看看我的尝试并建议我做错了什么吗？

总体思路是有一个 Company 类，其中包含一组客户。创建新客户实例时，我将他添加到公司并保留所有内容。

实体(仅显示相关部分，或者至少我希望如此)

public class Company implements Serializable {

    private static final long serialVersionUID = 146243652;

    private String id;
    private String name;
    private String website;
    private Set<Customer> customers;
    ... getters, setters etc

public class Customer implements Serializable {
    private static final long serialVersionUID = 864235654;

    private String name;
    private String surname;
    private String adress;
    private String id;
    private Company company;

customer.hbm.xml:

<hibernate-mapping>
    <class name="wa2.entities.Customer" table="CUSTOMER">
        <id column="ID" name="id" type="java.lang.String" />
        <property column="NAME" name="name" type="java.lang.String" />
        <property column="SURNAME" name="surname" type="java.lang.String" />
        <property column="ADRESS" name="adress" type="java.lang.String" />

         <many-to-one name="COMPANY" class="wa2.entities.Company">
             <column name="COMPANY_ID" not-null="true"></column> 
         </many-to-one> 
    </class>
</hibernate-mapping>

company.hbm.xml:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
    <class name="wa2.entities.Company" table="COMPANY">
        <id column="ID" name="id" type="java.lang.String" />
        <property column="NAME" name="name" type="java.lang.String" />
        <property column="WEBSITE" name="website" type="java.lang.String" />

        <set name="CUSTOMERS" table="CUSTOMER" fetch="select">
            <key>
                <column name="CUSTOMER_ID" not-null="true"></column>
            </key>
            <one-to-many class="wa2.entities.Customer"/>
        </set>
    </class>
</hibernate-mapping>

保存客户(这在一对多关系实现之前有效，所以我怀疑这段代码有什么问题):

        Customer customer = new Customer();

        String name = req.getParameter("name");
        customer.setName(name);
        String surname = req.getParameter("surname");
        customer.setSurname(surname);
        String adress = req.getParameter("adress");
        customer.setAdress(adress);

        String companyID = req.getParameter("companyId");
        Company company = repository.loadCompany(companyID);
        customer.setCompany(company);

        String id = UUID.randomUUID().toString();
        customer.setId(id);

        repository.saveCustomer(customer);

我希望我没有忘记任何相关部分。如果是这样，请告诉我，我将发布相关代码。非常感谢您的帮助!

编辑:感谢您的回复。看来我把名字的大写写错了。我改变了这一点，现在我无法延迟初始化角色集合:wa2.entities.Company.customers，无法初始化代理 - 无 session

Answer 1

由于这是一个映射异常，我猜它是在 session 工厂创建期间出现的，而不是在保存时出现的？另外，查看整个堆栈跟踪也会有所帮助。您的异常可能是由于映射文件和 bean 之间的属性名称不匹配引起的。请参阅Could not get constructor for org.hibernate.persister.entity.SingleTableEntityPersister .

在您的代码中，您有 name 属性值

<many-to-one name="COMPANY" class="wa2.entities.Company">
    <column name="COMPANY_ID" not-null="true"></column> 
</many-to-one>

和

<set name="CUSTOMERS" table="CUSTOMER" fetch="select">
     <key>
        <column name="CUSTOMER_ID" not-null="true"></column>
     </key>
     <one-to-many class="wa2.entities.Customer"/>
 </set>

大写，而您的 pojo 中的属性被命名为公司和客户。