Using getAtttributesNames in servlet

Question

Am trying to retrieve the data submitted from the HTML from in a servlet.Am using netbeans and am trying to get the enumeration returned by getAttributes(). The html is

   <html>
    <body>
        <center>
        <form name="Form1" action="http://localhost:8080/DemoWeb/TwoParServlet">
                <B>Color:</B>
                <select name="color" size="1">
                    <option value="Red">Red</option>
                    <option value="Green">Green</option>
                    <option value="Blue">Blue</option>
                </select>
                <br>
                <br>
                <B>Country:</B>
                <select name="country" size="1">
                    <option value="India">India</option>
                    <option value="Srilanka">Srilanka</option>
                    <option value="Chinae">China</option>
                </select>
                <br>
                <br>
                <input type=submit value="Submit">
        </form>
        </center>
    </body>
    </html>

The servlet is

public class TwoParServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {

        String color = request.getParameter("color");
        String country = request.getParameter("country");

        response.setContentType("text/html");
        PrintWriter pw = response.getWriter();
        pw.println("<p>The selected color is:  ");
        pw.println(color);
        pw.println("<p>The selected country is:  ");
        pw.println(country);

        Enumeration names;
        names = request.getAttributeNames();

        pw.println("<p> First value received = " + names.nextElement());
        //pw.println("<p> First value received = " + names.nextElement());


        pw.close();
}
}

When I run the project am getting this error

Exception report message description The server encountered an internal error that prevented it from fulfilling this request.

exception

java.util.NoSuchElementException
java.util.HashMap$HashIterator.nextEntry(HashMap.java:929)
java.util.HashMap$KeyIterator.next(HashMap.java:960)
java.util.Collections$2.nextElement(Collections.java:3665)
p1.TwoParServlet.doGet(TwoParServlet.java:36)
javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)

What might have gone wrong?

You must be looking for [`ServletRequest#getParameterMap()`](http://docs.oracle.com/javaee/7/api/javax/servlet/ServletRequest.html#getParameterMap()). — sp00m, Dec 23 '14 at 09:46
There is big difference between parameter and attribute. Read [here](http://stackoverflow.com/questions/5243754/difference-between-getattribute-and-getparameter) and [here](http://www.xyzws.com/servletfaq/what-is-the-difference-between-the-request-attribute-and-request-parameter/1) — Braj, Dec 23 '14 at 09:57

score 1 · Answer 1 · edited May 23 '17 at 11:57

1

You should use getParameterNames() instead of getAttributeNames.

Enumeration parameterNames = request.getParameterNames();

For more information to know difference between Attributes and Parameters see this question.

edited May 23 '17 at 11:57

Community

1
1

answered Dec 23 '14 at 10:03

Ali Sepehri.Kh

2,468
2
18
27

score 1 · Accepted Answer · answered Dec 23 '14 at 10:03

1

You Just check the size of names, it will be zero. so it means there is nothing returned from request.getAttributeNames().

use request.getParameterNames() instead of request.getAttributeNames().

answered Dec 23 '14 at 10:03

sumit kumar

602
3
11
26

Using getAtttributesNames in servlet

2 Answers2