JSP implements the method of putting information into XML _jsp programming

This article illustrates how JSP implementations put information into XML. Share to everyone for your reference, specific as follows:

One, JSP code:

Province: <select id= "province" Name= "province" onchange= "Jssubmit" () "> <option value=" Beijing "selected=" 
    > Beijing </option> 
    <option value= "Guangdong" > Guangdong </option> 
    <option value= "Hainan" > Hainan </option > 
  </select> 
: <select id= "City" name= "Cities" > 
    <option value= "Beijing" > Beijing </option > 
 </select>

Second, the AJAX code to create the server request code do not write, write onchange when the event Jssubmit bar:

function Jssubmit () { 
  createxmlhttprequest (); 
     var province = document.getElementById ("province"); 
  Resolves the client to the server to transmit Chinese garbled 
     var uri = "ajaxaction?value=" + encodeURI (encodeURI (Province.value)); 
  Xmlhttp.open ("POST", Uri, true); 
  Xmlhttp.setrequestheader ("Content-type", "application/x-www-form-urlencoded;") 
  Xmlhttp.onreadystatechange = processresponse;//callback function Ah! 
  xmlhttp.send (null); 
}

Third, the servlet

 public class Ajaxaction extends HttpServlet {private static final long Serialversionu 
 ID = 1L; 
 private static map<string, string[]> Map = new hashmap<string, string[]> (); 
  static {string[] Cities1 = {"Haikou", "Qionghai", "Sanya"}; 
  String[] Cities2 = {"Guangzhou", "Zhuhai", "Foshan", "Shenzhen"}; 
  String[] Cities3 = {"Beijing"}; 
  Map.put ("Beijing", Cities3); 
  Map.put ("Guangdong", Cities2); 
 Map.put ("Hainan", cities1); } St Method {string province = Request.getparameter ("value");//Resolve client transmits Chinese garbled String PROVICECN = Urldecoder.decode to Server (pr 
  Ovince, "UTF-8"); string[] Cities = map.get (PROVICECN); According to the province, find the corresponding city Response.setcontenttype ("Text/xml") which has been deposited into the map; 
  Charset=utf-8 "); StringBuffer buff=new stringbuffer ("<citylist>");///prepare the spelling string ... for (string city:cities) {Buff.ap 
    Pend ("<city>"). Append (city). Append ("</city>"); 
  } buff.append ("</citylist>");

Response.getwriter (). println (Buff.tostring ()); 

Four, the Ajax callback function

function ProcessResponse () { 
  if (xmlhttp.readystate = 4) { 
   if (Xmlhttp.status =) { 
    var cities = XMLHTTP.R Esponsexml.getelementsbytagname ("City"); 
    var displayselect = document.getElementById ("city"); 
    displayselect.innerhtml = null; 
    for (var i= 0; i < cities.length; i++) {    
     if (i = = 0) {       
     var a= xmlHttp.responseXML.getElementsByTagName ("City") [ i].firstchild.data;//use FirstChild method, other methods I use the text method no matter ~ I don't know what's going on 
      var op = new Option (A, A, true, true); 
     } else { 
      var a= xmlHttp.responseXML.getElementsByTagName ("City") [I].firstchild.data; 
      var op = new Option (A, a); 
      alert (a); 
     } 
     Displayselect.options[i] = op; 
    }     
   else { 
    Window.alert ("The requested page has an exception");}} 

I hope this article will help you with JSP program design.