Question

我试图用hibnate使用java List制作多对多的例子。我的代码如下，我得到了一些错误。如果有人可以帮我解决这个问题，那就太棒了

学生可以参加很多课程许多学生可以参加一门课程

                     Student ---->STUDENT_COURSE<-----Course

学生班：

public class Student implements java.io.Serializable 
{
    private long studentId;
    private String studentName;
    private List<Course> courses = new LinkedList<Course>();
        //other getters and setters

}

课程班级：

public class Course implements java.io.Serializable {

    private long courseId;
    private String courseName;
    private List <Student> Stu = new LinkedList <Student>();
        //other getters and setters
}

课程映射文件：

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated Dec 14, 2010 7:14:32 AM by Hibernate Tools 3.4.0.Beta1 -->
<hibernate-mapping>
    <class name="com.BiddingSystem.domain.Course" table="COURSE">
        <id name="courseId" type="long">
            <column name="COURSEID" />
            <generator class="native" />
        </id>
        <property name="courseName" type="java.lang.String">
            <column name="COURSENAME" />
        </property>
        <list name="Stu"  table="STUDENT_COURSE">
            <key>
                <column name="COURSEID" />
            </key>
            <many-to-many column="STUDENTID"  class="com.BiddingSystem.domain.Student" />
        </list>
    </class>
</hibernate-mapping>

学生制图文件：

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated Dec 14, 2010 7:14:32 AM by Hibernate Tools 3.4.0.Beta1 -->
<hibernate-mapping>
    <class name="com.BiddingSystem.domain.Student" table="STUDENT">
        <id name="studentId" type="long">
            <column name="STUDENTID" />
            <generator class="native" />
        </id>
        <property name="studentName" type="java.lang.String">
            <column name="STUDENTNAME" />
        </property>
        <list name="courses"  table="STUDENT_COURSE">
            <key>
                <column name="STUDENTID" />
            </key>
            <many-to-many column="COURSEID" class="com.BiddingSystem.domain.Course" />
        </list>
    </class>
</hibernate-mapping>

错误：

Initial SessionFactory creation failed.org.hibernate.InvalidMappingException: Could not parse mapping document from resource com/BiddingSystem/domain/Student.hbm.xml
[WARN] /biddingsystem/greet
java.lang.ExceptionInInitializerError
    at com.BiddingSystem.server.HibernateUtil.<clinit>(HibernateUtil.java:16)
    at com.BiddingSystem.server.GreetingServiceImpl.<init>(GreetingServiceImpl.java:33)
    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 resource com/BiddingSystem/domain/Student.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.HibernateUtil.<clinit>(HibernateUtil.java:12)
    ... 26 more
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)
    ... 33 more
Caused by: org.xml.sax.SAXParseException: The content of element type "list" must match "(meta*,subselect?,cache?,synchronize*,comment?,key,(index|list-index),(element|one-to-many|many-to-many|composite-element|many-to-any),loader?,sql-insert?,sql-update?,sql-delete?,sql-delete-all?,filter*)".
    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.handleEndElement(XMLDTDValidator.java:2017)
    at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.endElement(XMLDTDValidator.java:901)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEndElement(XMLDocumentFragmentScannerImpl.java:1782)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2938)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:648)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:140)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:511)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:808)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:737)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:119)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1205)
    at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:522)
    at org.dom4j.io.SAXReader.read(SAXReader.java:465)
    at org.hibernate.cfg.Configuration.addInputStream(Configuration.java:601)
    ... 34 more
[WARN] Nested in java.lang.ExceptionInInitializerError:
org.hibernate.InvalidMappingException: Could not parse mapping document from resource com/BiddingSystem/domain/Student.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.HibernateUtil.<clinit>(HibernateUtil.java:12)
    at com.BiddingSystem.server.GreetingServiceImpl.<init>(GreetingServiceImpl.java:33)
    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)
    ... 33 more
Caused by: org.xml.sax.SAXParseException: The content of element type "list" must match "(meta*,subselect?,cache?,synchronize*,comment?,key,(index|list-index),(element|one-to-many|many-to-many|composite-element|many-to-any),loader?,sql-insert?,sql-update?,sql-delete?,sql-delete-all?,filter*)".
    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.handleEndElement(XMLDTDValidator.java:2017)
    at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.endElement(XMLDTDValidator.java:901)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEndElement(XMLDocumentFragmentScannerImpl.java:1782)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2938)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:648)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:140)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:511)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:808)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:737)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:119)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1205)
    at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:522)
    at org.dom4j.io.SAXReader.read(SAXReader.java:465)
    at org.hibernate.cfg.Configuration.addInputStream(Configuration.java:601)

Answer 1

您需要使用Set而不是List。要映射List，您需要一个额外的列，该列指定列表中每个成员出现在（an或元素）的索引。

根据我的经验，最好避免使用Hibernate的List-mapping支持。

Answer 2

请看here。它可能会解决你的问题。

使用Java List进行多对多的双向映射

2 个答案: