java - Hibernate 级联继承

Question

我有 3 节课

用户<------个人用户<------管理员

示例用户映射文件:

<class name="com.BiddingSystem.Models.Users" table="USERS">

</class>

示例个人用户映射文件

<joined-subclass name="com.BiddingSystem.Models.PersonalUser" extends="com.BiddingSystem.Models.Users" table="PERSONALUSER" lazy="false"   cascade="all">

</joined-subclass>

示例管理员用户映射文件:

<joined-subclass cascade="all" name="com.BiddingSystem.Models.Administrator" extends="com.BiddingSystem.Models.PersonalUser" table="ADMINISTRATOR" lazy="false">

 </joined-subclass>

但是当我尝试删除管理员时，出现以下错误:

堆栈跟踪:

org.hibernate.InvalidMappingException: Could not parse mapping document from resource com/BiddingSystem/Models/Administrator.hbm.xml
    at org.hibernate.cfg.Configuration.addResource(Configuration.java:671)
    at org.hibernate.cfg.Configuration.parseMappingElement(Configuration.java:1679)
    at org.hibernate.cfg.Configuration.parseSessionFactory(Configuration.java:1647)
    at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1626)
    at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1600)
    at org.hibernate.cfg.Configuration.configure(Configuration.java:1520)
    at org.hibernate.cfg.Configuration.configure(Configuration.java:1506)
    at com.BiddingSystem.server.ServiceImpl.<init>(ServiceImpl.java:63)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at java.lang.Class.newInstance0(Class.java:355)
    at java.lang.Class.newInstance(Class.java:308)
    at org.mortbay.jetty.servlet.Holder.newInstance(Holder.java:153)
    at org.mortbay.jetty.servlet.ServletHolder.getServlet(ServletHolder.java:339)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:463)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:362)
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:729)
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.handler.RequestLogHandler.handle(RequestLogHandler.java:49)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:324)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:505)
    at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:843)
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:647)
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211)
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:395)
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:488)
Caused by: org.hibernate.InvalidMappingException: Could not parse mapping document from invalid mapping
    at org.hibernate.cfg.Configuration.addInputStream(Configuration.java:604)
    at org.hibernate.cfg.Configuration.addResource(Configuration.java:668)
    ... 32 more
Caused by: org.xml.sax.SAXParseException: Attribute "cascade" must be declared for element type "joined-subclass".
    at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:195)
    at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:131)
    at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:384)
    at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:318)
    at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.addDTDDefaultAttrsAndValidate(XMLDTDValidator.java:1275)
    at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.handleStartElement(XMLDTDValidator.java:1940)
    at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.startElement(XMLDTDValidator.java:764)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:400)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2755)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:648)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:140)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:511)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:808)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:737)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:119)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1205)
    at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:522)
    at org.dom4j.io.SAXReader.read(SAXReader.java:465)
    at org.hibernate.cfg.Configuration.addInputStream(Configuration.java:601)
    ... 33 more

Answer 1

根据:http://docs.jboss.org/hibernate/core/3.6/reference/en-US/html_single/#d0e6847 (特别是 5.1.6.2)，“cascade”似乎不是 .hbm.xml 文件中 join-subclass 子句的允许属性。

我很确定，当您以这种方式进行继承时，删除子类将自动删除其父类的表数据。