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[SOLVED] Ajax Servlet : How to give path of .java file in req.open(GET,url,true)

Verve

By Verve
in Javascript Help

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Verve Newbie

Verve

Posted
Posted

Hi,

 

I am new to ajax. I am using a jsp from which a servelt is called which will do validation. I running application from tomcat. But in firebug following error is shown :

          req.responseXML has no properties

          var message = req.responseXML.getElementsByTagName("valid")[0].child

 

If in url(see jsp below) i am not giving .java then file not found error is shown. I tried by calling same code from a jsp and gave its path in url and it was working. I have no idea why it is not calling java file. please help !!!!!!!!!!!!!

 

Files are given below, both files are in same folder

 

Validate.jsp

 

<html>

<head>

<script type="text/javascript">

var req;

var target;

var isIE;

function initRequest(url) {

    if (window.XMLHttpRequest) {

        req = new XMLHttpRequest();

    } else if (window.ActiveXObject) {

        isIE = true;

        req = new ActiveXObject("Microsoft.XMLHTTP");

    }

}

 

function validateUserId() {

    if (!target){ target = document.getElementById("userid");}

var url  = "http://localhost:8080/XXAjax/ValidationServlet.java?id=" + escape(target.value);

alert(url);

  initRequest(url);

    req.onreadystatechange = processRequest;

    req.open("GET", url, true);

    req.send(null);

}

 

 

function processRequest() {

    if (req.readyState == 4) {

 

        if (req.status == 200) {

            var message = req.responseXML.getElementsByTagName("valid")[0].childNodes[0].nodeValue;

            setMessageUsingDOM(message);

            var submitBtn = document.getElementById("submit_btn");

            if (message == "false") {

              submitBtn.disabled = true;

            } else {

              submitBtn.disabled = false;

            }

        }

    }

}

 

// This function is not used for now. You will use this later.

function setMessageUsingInline(message) {

    mdiv = document.getElementById("userIdMessage");

    if (message == "false") {

      mdiv.innerHTML = "<div style=\"color:red\">Invalid User Id</div>";

    } else {

      mdiv.innerHTML = "<div style=\"color:green\">Valid User Id</div>";

    } 

}

 

 

// (5) Function in which message indicating the validity of the data gets displayed

// through the "userIdMessage" <div> element.

function setMessageUsingDOM(message) {

    var userMessageElement = document.getElementById("userIdMessage");

    var messageText;

    if (message == "false") {

        userMessageElement.style.color = "red";

        messageText = "Invalid User Id";

    } else {

        userMessageElement.style.color = "green";

        messageText = "Valid User Id";

    }

    var messageBody = document.createTextNode(messageText);

    // if the messageBody element has been created simple replace it otherwise

    // append the new element

    if (userMessageElement.childNodes[0]) {

        userMessageElement.replaceChild(messageBody, userMessageElement.childNodes[0]);

    } else {

        userMessageElement.appendChild(messageBody);

    }

}

 

function disableSubmitBtn() {

    var submitBtn = document.getElementById("submit_btn");

    submitBtn.disabled = true;

}

</script>

<title>Form Data Validation using AJAX</title>

</head>

 

<body onload="disableSubmitBtn()">

 

  <form name="ank"  method="GET">

  <input type="hidden" name="action" value="create"/>

  <table border="0" cellpadding="5" cellspacing="0">

    <tr>

    <td><b>User Id:</b></td>

    <td>

          <input    type="text"

                size="20" 

                  id="userid"

                name="id"

            onkeyup="validateUserId()">

    </td>

    <%-- The "userIdMessage" div element specifies the location where input validation

            message gets displayed. --%>

    <td>

      <div id="userIdMessage"></div>

    </td>

    </tr>

    <tr>

    <td align="right" colspan="2">

      <input id="submit_btn" type="Submit" value="Create Account">

    </td>

    <td></td>

    </tr>

  </table>

  </form>

</body>

</html>

 

ValidationServlet.java

 

import java.io.*;

import javax.servlet.*;

import javax.servlet.http.*;

import java.util.*;

 

public class ValidationServlet extends HttpServlet {

   

    private ServletContext context;

    private HashMap accounts = new HashMap();

 

    // Initialize the "accounts" hashmap.  For the sake of this exercise,

    // two accounts are created with names "greg" and "duke" during

    // initialization of the Servlet.

    public void init(ServletConfig config) throws ServletException {

        this.context = config.getServletContext();

        accounts.put("greg","account data");

        accounts.put("duke","account data");

    }

   

    public  void doGet(HttpServletRequest request, HttpServletResponse  response) throws IOException, ServletException {

       

        // Extract the data of the input form field whose name is "id"

        String targetId = request.getParameter("id");

 

     

        if ((targetId != null) && !accounts.containsKey(targetId.trim())) {

            response.setContentType("text/xml");

            response.setHeader("Cache-Control", "no-cache");

            response.getWriter().write("<valid>true</valid>");

        } else {

            response.setContentType("text/xml");

            response.setHeader("Cache-Control", "no-cache");

            response.getWriter().write("<valid>false</valid>");

        }

       

    }

 

    public  void doPost(HttpServletRequest request, HttpServletResponse  response)

        throws IOException, ServletException {

 

        String targetId = request.getParameter("id");

        if ((targetId != null) && !accounts.containsKey(targetId.trim())) {

            accounts.put(targetId.trim(), "account data");

            request.setAttribute("targetId", targetId);

            context.getRequestDispatcher("/Test.html").forward(request, response);

        } else {

            context.getRequestDispatcher("/error.jsp").forward(request, response);

        }

    }

   

}

 

Thanks in advance .....

Verve

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