Lets say that you have a following simple application:
<form action="helloServlet" method="post">
Give name:<input type="text" name="name" />
<input type="submit" value="Send"/>
</form>
And a servlet handling that form:
package org.servlets.hello;
import java.io.IOException;
import java.io.PrintWriter;
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(name="helloServlet", urlPatterns={"/helloServlet"})
public class helloServlet extends HttpServlet {
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
String name = request.getParameter("name");
PrintWriter out = response.getWriter();
try {
out.println("<html>");
out.println("<head>");
out.println("<title>Servlet helloServlet</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>Hello " + name + "</h1>");
out.println("</body>");
out.println("</html>");
} finally {
out.close();
}
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
}
Now this works perfectly when it is ran from a web page located at the "Web Pages" folder but when I try to do the same in a subfolder in Web Pages I am given 404 error (The requested resource () is not available.). Am I supposed to change something to make the subfolder a valid location to call for a servlet?
If the POST action url starts with "/" it is absolute. Or else, it is relative to the current page
Because the post url <form action="helloServlet" , helloServlet is relative to the current path.
This is how the helloservlet url will be accessed:
Current Page Servlet URL
Usage 1 /form.html /helloservlet
Usage 2 /subfolder/form.html /subfolder/helloservlet
And in your case, the Usage 1 works because Servlet is mapped to /helloservlet.
Solution:
Modify line
<form action="helloServlet" method="post">
to
<form action="/{contextPath}/}helloServlet" method="post">
I think your context path is not default "/" context path. In that case, you should be having url relative to the domain. Replace {contextpath} with the actual context path.