Question

I just starting learning about servlets yersterday so I’m a newbie. I read a tutorial and made the following program to track the use of a link:

package red;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/Redirection")
public class Redirection extends HttpServlet {
    private static final long serialVersionUID = 1L;
    private String referrer;
    private String target;

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

        try {
            getURLs(request);
        }
        catch(Exception e)
        {
            response.sendError(500, "Target parameter not specified");
            return;
        }
        response.sendRedirect(target);
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        this.doGet(request, response);
    }

    public void getURLs(HttpServletRequest request)
    {
        referrer = request.getParameter("referrer");
        if(referrer == null || 0 == referrer.length())
        {
            referrer = new String("");
        }

        target = request.getParameter("target");
        if(target == null || target.equals(""))
        {
            throw new IllegalArgumentException();
        }
    }
}

But when I teste it(Eclipse with Tomcat) i get this:

HTTP Status 500 - Target parameter not specified

How do I specify a target parameter in eclipse so I can run this program ?

Sorry for the beginner question.

Answer 1

Well you don’t really know what’s going on here. Maybe you’re getting a different exception – you’re giving that error message whatever goes wrong. You should log exactly what’s being thrown. You also shouldn’t generally catch Exception yourself – catch more specific exceptions.

Anyway, normally to include that sort of parameter, you’d just put it in the URL:

/Redirect?target=x&referrer=y