创建XPath对象:
XPathFactory factory = XPathFactory.newInstance();
this.xpath = factory.newXPath();
创建Document对象:(DOM解析)
//JDK提供的文档解析工厂对象
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
//创建一个DocumentBuilder对象
DocumentBuilder builder = factory.newDocumentBuilder();
//解析输入源的xml数据为一个Document文件
return builder.parse(inputSource);
创建Configuration对象
new Configuration()
注册类型别名
初始化Configuration对象的一些成员变量的默认值