休眠中的復合主鍵問題

Question

我正在創建一個休眠應用程序，在其中我想創建一個復合主鍵 。 以下是我編寫的映射文件：

<?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="Fold.ChildrenPark" table="ChildrenPark">
    <composite-id>
    <key-property name="date" not-null="true"/>
    <key-property name="valveOffTime" not-null="true"/>
    <key-property name="valveOnTime" not-null="true"/>
    </composite-id>
    <property name="overHeadTankLevelAfterFilling"/>
    <property name="overHeadTankLevelBeforeFilling"/>
    <property name="rank"/>
  </class>
</hibernate-mapping>

但是我得到如下異常：

 - 1689 [http-listener-1(4)] ERROR org.hibernate.util.xml.ErrorLogger -
   Error parsing XML (11) : Attribute "not-null" must be declared for
   element type "key-property". Severe:   1717 [http-listener-1(4)] WARN
   org.hibernate.util.DTDEntityResolver - recognized obsolete hibernate
   namespace http://hibernate.sourceforge.net/. Use namespace
   http://www.hibernate.org/dtd/ instead. Refer to Hibernate 3.6
   Migration Guide! Severe:   1719 [http-listener-1(4)] ERROR
   org.hibernate.util.xml.ErrorLogger - Error parsing XML (2) :
   Attribute "not-null" must be declared for element type
   "key-property". Info:   Exception in insertion of data:
   org.hibernate.InvalidMappingException: Unable to read XML

所以我想知道這段代碼中缺少什么內容。我在網上搜索但沒有發現有用的東西，這意味着什么？

Answer 1

有很多事情 ：

1 /從更改您的dtd：

<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

至：

<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

這將刪除有關過時的休眠名稱空間的警告

2 /刪除密鑰屬性的not-null屬性，因為PK屬性不能為null，所以該屬性對於密鑰屬性不存在。