Ajax实现二级联动菜单

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 二级联动示例 
 
   请选择  北京  天津  山东   请选择 
 
 
 

 package com; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /*** * * @author zdw * */ public class SelectServlet extends HttpServlet { private static final long serialVersionUID = 1L; public SelectServlet() { super(); } public void destroy() { super.destroy(); } public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //  response.setCharacterEncoding("GBK"); response.setContentType("text/xml"); response.setHeader("Cache-Control", "no-cache"); request.setCharacterEncoding("GBK"); response.setCharacterEncoding("UTF-8"); String targetId = request.getParameter("id").toString(); System.out.println(targetId); // 获得请求中参数为id的值 String xml_start = ""; String xml_end = ""; String xml = ""; if (targetId.equalsIgnoreCase("0")) { xml = "0请选择"; } else if (targetId.equalsIgnoreCase("1")) { xml = "1昌平"; xml += "2丰台"; xml += "3海淀"; xml += "4朝阳"; } else if (targetId.equalsIgnoreCase("2")) { xml = "1塘沽区"; xml += "2汉沽区"; xml += "3大港区"; xml += "4东丽区"; } else {// 如果是3,则返回下面的字符 xml = "1济南"; xml += "2青岛"; xml += "3淄博"; xml += "4枣庄"; } String last_xml = xml_start + xml + xml_end; response.getWriter().write(last_xml); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } public void init() throws ServletException { } }

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菜单二级联动参考价值北京