2.2 使用 JAXP 对XML文档进行SAX解析

使用JAXP 对 XML文档进行 SAX解析：

 public class Demo1 {

     /**
      *  使用JAXP对XML文档进行SAX解析
      * @throws Exception
      * @throws ParserConfigurationException
      */
     public static void main(String[] args) throws ParserConfigurationException, Exception {

         //1.创建解析工厂
          SAXParserFactory factory = SAXParserFactory.newInstance();

         //2.得到解析器
          SAXParser sp = factory.newSAXParser();

         //3.得到读取器
          XMLReader reader = sp.getXMLReader();

         //4.设置内容处理器
          ListHandler handler = new ListHandler();
         reader.setContentHandler(handler);

         //5.读取XML文档内容
         reader.parse("src/book.xml");
     }

 }

 //得到XML文档所有内容
 class ListHandler implements ContentHandler {

     @Override
     public void startElement(String uri, String localName, String qName,
             Attributes atts) throws SAXException {
         System.out.println("<" + qName + ">");

         //打印标签的属性
         for(int i = 0;atts != null && i<atts.getLength();i++) {  //防止某些时候属性值为空时，抛异常  所以再加个条件atts != null
             String attName = atts.getQName(i);
             String attValue = atts.getValue(i);
             System.out.println(attName + "=" + attValue);
         }

     }

     @Override
     public void characters(char[] ch, int start, int length)
             throws SAXException {
         System.out.println(new String(ch,start,length));

     }

     @Override
     public void endElement(String uri, String localName, String qName)
             throws SAXException {
         System.out.println("</" + qName + ">");

     }

     @Override
     public void setDocumentLocator(Locator locator) {

     }

     @Override
     public void startDocument() throws SAXException {
         // TODO Auto-generated method stub

     }

     @Override
     public void endDocument() throws SAXException {
         // TODO Auto-generated method stub

     }

     @Override
     public void startPrefixMapping(String prefix, String uri)
             throws SAXException {
         // TODO Auto-generated method stub

     }

     @Override
     public void endPrefixMapping(String prefix) throws SAXException {
         // TODO Auto-generated method stub

     }

     @Override
     public void ignorableWhitespace(char[] ch, int start, int length)
             throws SAXException {
         // TODO Auto-generated method stub

     }

     @Override
     public void processingInstruction(String target, String data)
             throws SAXException {
         // TODO Auto-generated method stub

     }

     @Override
     public void skippedEntity(String name) throws SAXException {
         // TODO Auto-generated method stub

     }

 }