使用 JScience 解析 mathml 文档

Question

我试图使用 JScience 解析 mathml 文档，但没有成功。以下是我的一段代码。

import JSci.io.*;
import JSci.mathml.*;
  .
  .
public class ParsingMathML(){
 try {
        ....
        //inputFile is an xml file containing mathml code
 InputSource file = new InputSource(new FileReader(inputFile));  
 MathMLParser parser = new MathMLParser();
 parser.parse(file);

 Object[] parseList = parser.translateToJSciObjects();
}catch (Exception e) {
 e.printStackTrace();
}
}

我从这里得到了错误，所以我无法进一步做任何事情。以下是 StackTrace：

Exception in thread "AWT-EventQueue-0" java.lang.NoClassDefFoundError: JSci/maths/fields/Ring$Member
 at JSci.io.MathMLParser.translateToJSciObjects(Unknown Source)
 at JSci.io.MathMLParser.translateToJSciObjects(Unknown Source)
 at mathML.ProcessMathML.processFile(ParsingMathML.java:109)
 at mathML.ProcessMathML.actionPerformed(ParsingMathML.java:72)
 at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
 at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
 at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
 at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
 at javax.swing.AbstractButton.doClick(Unknown Source)
 at javax.swing.plaf.basic.BasicMenuItemUI.doClick(Unknown Source)
 at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(Unknown Source)
 at java.awt.Component.processMouseEvent(Unknown Source)
 at javax.swing.JComponent.processMouseEvent(Unknown Source)
 at java.awt.Component.processEvent(Unknown Source)
 at java.awt.Container.processEvent(Unknown Source)
 at java.awt.Component.dispatchEventImpl(Unknown Source)
 at java.awt.Container.dispatchEventImpl(Unknown Source)
 at java.awt.Component.dispatchEvent(Unknown Source)
 at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
 at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
 at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
 at java.awt.Container.dispatchEventImpl(Unknown Source)
 at java.awt.Window.dispatchEventImpl(Unknown Source)
 at java.awt.Component.dispatchEvent(Unknown Source)
 at java.awt.EventQueue.dispatchEvent(Unknown Source)
 at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
 at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
 at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
 at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
 at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
 at java.awt.EventDispatchThread.run(Unknown Source)
Caused by: java.lang.ClassNotFoundException: JSci.maths.fields.Ring$Member
 at java.net.URLClassLoader$1.run(Unknown Source)
 at java.security.AccessController.doPrivileged(Native Method)
 at java.net.URLClassLoader.findClass(Unknown Source)
 at java.lang.ClassLoader.loadClass(Unknown Source)
 at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
 at java.lang.ClassLoader.loadClass(Unknown Source)
 at java.lang.ClassLoader.loadClassInternal(Unknown Source)
 ... 31 more

另外，有人知道如何使用 MathMLApplyElementImpl、MathMLDocumentImpl 或 JSci.mathml 包中的任何其他类吗？

如果您能提供一些有关如何解析 mathml 文档的代码示例，那就太好了。

任何想法都将受到高度赞赏。 谢谢

Answer 1

关于您的精确错误，似乎类 JSci.maths.fields.Ring$Member 不存在，它在方法 JSci.io.MathMLParser.translateToJSciObjects 中抛出 ClassNotFoundException 。

我们来看看这个源代码。
在 MathMLParser 中，Ring.Member 最显着的用法是作为返回值。但它可以在很多地方找到。
而且，由于 Ring.Member 位于 JSci.maths.fields 中，它似乎与 MathMLParser 位于同一个 JAR 中，因此我猜您的问题比简单的 ClassNotFoundException 复杂得多。

首先，您可以打开 JScience jar 来确保 JSci.maths.fields.Ring$Member 确实存在吗？

如果不是这种情况，您是否在同一应用程序中使用多个类加载器？ （诸如 OSGi 之类的东西）