通过xml解析创建对象

Question

I am a new programmer and I am having trouble with a project I am working on. I am trying to parse a xml file using a Saxparser instead of getting user input. My xml file has multiple types of "citations" such as books, journal articles ext. I am having trouble filling an object hierarchy by parsing an xml, I have the appropriate classes with their respective constructers and getter and setter methods to create the objects. My only question is how to create these objects while parsing by overriding these methods below in my main class.

      public class main extends DefaultHandler{

          @Override
           public void startElement(String s, String s1, String tagname, Attributes attr ) throws SAXException{
           if(tagname.equals("Book")){
            }

           }

          @Override
          public void characters(char [] ac, int i, int s)throws SAXException{

          }

          @Override 
          public void endElement(String s, String s1, String tag)throws SAXException{

          }


           public static void main(String[] args) throws IOException,      ParserConfigurationException, SAXException {
           // Create scanner
           Scanner OswegoNote = new Scanner(System.in);
          //Create a parser factory
           SAXParserFactory factory = SAXParserFactory.newInstance();
           //make the parser
           SAXParser saxParser = factory.newSAXParser();
           XMLReader parser = saxParser.getXMLReader();
           //create a handler
           main handler = new main();
           //tell the parser to use the handler
          parser.setContentHandler(handler);
          //Read and parse the document
          parser.parse("xmlFile.xml");

Below is part of the xml file I am attempting to parse and retrieve the shown values for each citation type.

        <Citation>
              <Book>
                <Name>A Wavelet Tour of Signal Processing</Name>
                <Publisher>Academic Press</Publisher>
                <PublicationDate>01/01/2009</PublicationDate>
                <PublicationPlace>Burlington,MA</PublicationPlace>
              <Authors>
                <author>Stephanie M Mallot</author>
                </Authors>
              <Keywords>
                <Keyword>DSP</Keyword>
                <Keyword>Wavelets</Keyword>
              <Keyword>Sparse Data</Keyword>
              </Keywords>
            </Book>
        </Citation>


        <Citation>
           <JournalArticle>
              <Name>The attractions of stupidity</Name>
              <TitleOfJournal>The St. Croix Review</TitleOfJournal>
              <PublicationDate>October, 2002</PublicationDate>
              <volNumber>30</volNumber>
              <IssueNumber>2</IssueNumber>
            <Authors>
               <author>Harry Hank Hirsh</author>
               <author>Mark Harold Coen</author>
               <author>Michael Charles Mozer</author>
           </Authors>
               <Pages StartPage="6" EndPage="10"/>
           <Keywords>
               <Keyword>Psychology</Keyword>
            <Keyword>Sociology</Keyword>
            <Keyword>Intelligence</Keyword>
            <Keyword>Sexuality</Keyword>
           </Keywords>
         </JournalArticle>
       </Citation>

Answer 1

Start an internal data model for the object at the startElement event which represents the object. Accumulate data for the object in variables/data-structures in your program. When you reach the endElement for that object, use the data you've stored to construct/configure the object.

If the objects can be nested, you may need to maintain a context stack. If they're related in other ways, you may have to map IDs and IDREFs to references to those objects.

Many examples can be found on the web. Several competing semi-standard representations exist, plus a whole bunch of custom approaches.