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Ajax+servlet instance

Source: Internet
Author: User
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Ajax|servlet

Ajax asynchronous request, the servlet produces random data, HTML page no refresh display.
Operating Environment: Jdk1.5+tomcat 5.5

First, Ajaxservlet.java

Package Com;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 Java.util.random;public class Ajaxservlet extends HttpServlet{private Static final String content_type= "Text/xml; charset=gb2312 ";p ublic void Init () throws Servletexception{}public void Doget (HttpServletRequest request, HttpServletResponse response) throws servletexception,ioexception{Response.setcontenttype (Content_Type); Response.setheader ("Cache-control", "No-cache"); Response.setheader ("Pragma", "No-cache"); Response.setdateheader ("Expires", 0);  PrintWriter out=response.getwriter (); String action=request.getparameter ("action"); if (("Send"). Equals (action) {    Random Random = new Random ();  string aa=integer.tostring (Math.Abs (Random.nextint ()));  string bb=integer.tostring (Math.Abs ( Random.nextint ());  String Cc=inteGer.tostring (Math.Abs (Random.nextint ()));  String dd=integer.tostring (Math.Abs (Random.nextint ()));  StringBuffer sb=new stringbuffer ();  sb.append (AA);  sb.append ("@@@");  sb.append (BB);  Sb.append ("@@@");  sb.append (CC);  sb.append ("@@@");  sb.append (DD);  Out.write (sb.toString ()) ;  out.close (); }}}

Second, testajax.html
<title>AJAX.html</title>
<script type= "Text/javascript" >

function GetResult () {  var url = "/tajax/aajaxservlet?action=send";  if window. XMLHttpRequest) {     req = new XMLHttpRequest ();  }else if (window. ActiveXObject) {     req = new ActiveXObject ("Microsoft.XMLHTTP");  }   if ( Req) {      Req.open ("Get", url, True);      Req.onreadystatechange = complete;      req.send (null);  }}/* Parse-returned text document * * function complete () {  if (req.readystate = 4) {     if (Req.status =) {   & nbsp;  //Alert (Req.responsetext);       var strresult = unescape ( Req.responsetext);      var arrresult = strresult.split ("@@@");       Removerow (); //Delete previous data .      NUM1 = arrresult[0]; Value of field num1       num2 = arrresult[1]; WordValue of segment num2       num3 = arrresult[2];      num4 = arrresult[3];       row1= tb.insertrow ();      cell1 = Row1.insertcell ();       Cell1.innertext = num1;      cell2 = Row1.insertcell ();       cell2.innertext = num2;      row2= tb.insertrow ();       Cell3 = Row2.insertcell ();      cell3.innertext = num3;       CELL4 = Row2.insertcell ();      cell4.innertext = num4;   } else {       alert (' There is a problem with the request. ');     }  }}  function Removerow () {//Left first row header, all remaining data deleted .    var irows = tb.rows.length;    for (var i=0;i< irows-1;i++) {       Tb.deleteRoW (1);   }} function Myshow () {//2 seconds automatically refresh once, 2 seconds to get data .  timer = Window.setinterval ("GetResult ()", ); }

</script>

<body >
<table width= "47%" height= "border=" 0 "cellpadding=" 1 "cellspacing=" 0 "id=" TB ">
<tr><td> Code </td>
<td> Price </td>
</tr>
</table>

<form>
<p> Enter Stock code:
<input type= "text" size= "name=" "Phone" id= "Phone"/>
</p>
<p> Number of transactions you:</p>
<p><textarea name= "Order" rows= "6" cols= "M" id= "order" ></textarea></p>
<p><input type= "Submit" value= "submitted" id= "Submission"/></p>
</form>

</body>

Third, Web.xml

<?xml version= "1.0" encoding= "Iso-8859-1"?>

<web-app xmlns= "HTTP://JAVA.SUN.COM/XML/NS/J2EE"
Xmlns:xsi= "Http://www.w3.org/2001/XMLSchema-instance"
xsi:schemalocation= "Http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
version= "2.4" >

<display-name>welcome to Tomcat</display-name>
<description>
Welcome to Tomcat
</description>

<servlet>
<servlet-name>AajaxServlet</servlet-name>
<servlet-class>com.ajaxServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>AajaxServlet</servlet-name>
<url-pattern>/AajaxServlet</url-pattern>
</servlet-mapping>


</web-app>


Run diagram:



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