编写SAX解析器时有一个巧妙的窍门：允许
ContentHandler在解析时更改
XMLReader的。这允许将不同元素的解析逻辑分为多个类，从而使解析更具模块化和可重用性。当一个处理程序看到其结束元素时，它将切换回其父级。您将实现多少个处理程序。代码如下所示：
public class RootHandler extends DefaultHandler { private XMLReader reader; private List<Team> teams; public RootHandler(XMLReader reader) { this.reader = reader; this.teams = new linkedList<Team>(); } public void startElement(String uri, String localName, String name, Attributes attributes) throws SAXException { if (name.equals("team")) { // Switch handler to parse the team element reader.setContentHandler(new TeamHandler(reader, this)); } }}public class TeamHandler extends DefaultHandler { private XMLReader reader; private RootHandler parent; private Team team; private StringBuilder content; public TeamHandler(XMLReader reader, RootHandler parent) { this.reader = reader; this.parent = parent; this.content = new StringBuilder(); this.team = new Team(); } // characters can be called multiple times per element so aggregate the content in a StringBuilder public void characters(char[] ch, int start, int length) throws SAXException { content.append(ch, start, length); } public void startElement(String uri, String localName, String name, Attributes attributes) throws SAXException { content.setLength(0); } public void endElement(String uri, String localName, String name) throws SAXException { if (name.equals("name")) { team.setName(content.toString()); } else if (name.equals("team")) { parent.addTeam(team); // Switch handler back to our parent reader.setContentHandler(parent); } }}
