基于Ajax的二级联动下拉列表.rar

package fox.math.kmust; import java.io.File; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import org.w3c.dom.Document; import org.xml.sax.SAXException; public class DoubleSelect extends HttpServlet { @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String xmlRealPath = getServletContext().getRealPath("/Data.xml"); File xmlFile = new File(xmlRealPath); Document document = null; try { document = DocumentBuilderFactory.newInstance() .newDocumentBuilder().parse(xmlFile); } catch (SAXException e) { System.err.println("SAX错误：" + e.getMessage()); } catch (ParserConfigurationException e) { System.err.println("配置错误：" + e.getMessage()); } String id = request.getParameter("id"); String value = document.getElementsByTagName("class").item( Integer.parseInt(id)).getFirstChild().getNodeValue().trim(); response.setContentType("text/xml"); response.setCharacterEncoding("gbk"); PrintWriter out = response.getWriter(); out.print(value); out.close(); } }