原代码：
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse(xmlPath);\\直接将路径名给builder
改进后的代码：
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse("file:///" + xmlPath);//加上file://标识符表示本地的文件加上file://标识符表示本地的文件。