个回答

• 君士坦丁11

  2017-06-03 16:42:04

  已采纳

  我感觉这个startElement方法应该是JAVA官方类的源代码中的方法，只有用法。当你主函数调用parse（uri，dh）时，parse方法就已经把xml文件进行解析，并且获取了你问题里的参数，这都是官方类的操作，我们看不到的。

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• 政政0213

  2018-10-26 16:31:17

  请注意看参数

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• 政政0213

  2018-10-26 16:30:37

  SAXParserFactory saxParserFactory = SAXParserFactory.newInstance();

  SAXParser saxParser = saxParserFactory.newSAXParser();
  

  SaxParserHandler saxParserHandler = new SaxParserHandler();

  saxParser.parse("books.xml", saxParserHandler);

  //parse（） 

  public void parse(String uri, DefaultHandler dh)

          throws SAXException, IOException {

          if (uri == null) {

              throw new IllegalArgumentException("uri cannot be null");

          }

  
  

          InputSource input = new InputSource(uri);

          this.parse(input, dh);//------------执行到此处

      }

  
  

  public void parse(InputSource is, DefaultHandler dh)

          throws SAXException, IOException {

          if (is == null) {

              throw new IllegalArgumentException("InputSource cannot be null");

          }

  
  

          XMLReader reader = this.getXMLReader();

          if (dh != null) {

              reader.setContentHandler(dh);

              reader.setEntityResolver(dh);

              reader.setErrorHandler(dh);

              reader.setDTDHandler(dh);

          }

          reader.parse(is);//----------

      }

  
  

   public void parse (InputSource input)

          throws IOException, SAXException;

  //----------

  void org.xml.sax.XMLReader

  
  

  
  

  
  

  
  

   /**

       * Receive notification of the start of an element.

       *

       * <p>By default, do nothing.  Application writers may override this

       * method in a subclass to take specific actions at the start of

       * each element (such as allocating a new tree node or writing

       * output to a file).</p>

       *

       * @param uri The Namespace URI, or the empty string if the

       *        element has no Namespace URI or if Namespace

       *        processing is not being performed.

       * @param localName The local name (without prefix), or the

       *        empty string if Namespace processing is not being

       *        performed.

       * @param qName The qualified name (with prefix), or the

       *        empty string if qualified names are not available.

       * @param attributes The attributes attached to the element.  If

       *        there are no attributes, it shall be an empty

       *        Attributes object.

       * @exception org.xml.sax.SAXException Any SAX exception, possibly

       *            wrapping another exception.

       * @see org.xml.sax.ContentHandler#startElement

       */

      public void startElement (String uri, String localName,

                                String qName, Attributes attributes)

          throws SAXException

      {

          // no op

      }

  
  

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