Getting user input from HTML to Java servlet using GlassFish

Question

This is my first attempt at HTML interaction with Java. I Understand that I need to use a Java servlet and an HTML index. I am doing this over a local GlassFish 4 server.

What I would like is a simple user input to my Java EE (Eclipse v4.5 (Mars)) project. I am not positive how to do this. I have watched tutorials and read multiple guides, but none explicitly explain the interaction. (This is why I know I need a servlet.)

So here is my setup thus far, and I have no clue where to go from here.

Java servelet

package servletPackage1;
import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class GetUserInputServlet extends HttpServlet {
    /**
     *
     */
    private static final long serialVersionUID = 1L;
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
        throws ServletException, IOException{
        String userInput = req.getParameter("UserInput");

    }
}

Again I am not positive that this is even set up correctly, but how do I get the input from my index file?

Here is my index.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "https://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>DSS</title>
</head>
<body>
<form action="DATASEARCH/GetUserInputServlet" method="get">
  Search for details:<br>
  <input type="text" name="text/plain" value="Enter search criteria">
  <br>

  <br><br>
  <input type="submit" class="btn-success btn-md" style="margin-right:5px" id="T1" value="Submit">
</form>

</html>

I have found out that I need to have my deployment descriptor (web.xml file). I have created one, but I am still receiving a 404 upon submission. The XML is below:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>DATASEARCH</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>Index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
</web-app>

This will be connected to a much larger project (which is finished and works perfectly) to search across a database. I only need to get the user input across a web application. NEW TO HTML also.

For an answer I am looking for:

What is wrong with what I have done? (I am getting a 404 error when I click my submit button)
How do I get the input into a Java variable casted as a string?

For now I will only be using ONE servlet as I only need access to a single user input from a single page. I do not understand this servlet mapping as well as I should, but I can not find information on how to map. Any help would be appreciated.

I also just noticed that my servlet is NOT being identified by eclipse as a servlet (Is this automatic? or do i need to tell the project that it is a servlet?) If there is any clarification needed... don't hesitate to ask — Jason V, May 22 '17 at 12:45
Please post you web.xml. 404 means mapping is incorrect. so on submit you are trying to send something to the `:[]DATASEARCH/GetUserInputServlet` url which cannot be found. — StanislavL, May 22 '17 at 12:47
I might sound stupid here, but i have no XML? i didn't write any? is this analagous to my .jsp? — Jason V, May 22 '17 at 12:51
The how your servlet is registered? How app server knows which URL should be processed by which servlet? — StanislavL, May 22 '17 at 12:55
Great question i suppose that is something i will have to research because i don't know. :) Also, i am noticing that my servlet is not identified as a servlet... is this done automatically or do i have to tell the project that it is intended ot be a servlet? — Jason V, May 22 '17 at 12:57
Start from https://docs.oracle.com/cd/E13222_01/wls/docs92/webapp/configureservlet.html — StanislavL, May 22 '17 at 12:58
well first add a [Deployment Descriptor](https://stackoverflow.com/questions/11658104/where-is-web-xml-in-eclipse-projects) to your project and then configure the [Servlet](https://stackoverflow.com/questions/18889681/mapping-servlet-in-web-xml) — Priyank Jain, May 22 '17 at 13:00

score 1 · Accepted Answer · answered May 22 '17 at 17:29

You need to add servlet mapping in your deployment descriptor (web.xml)

    <servlet-mapping>
        <servlet-name>GetUserInputServlet</servlet-name>
        <url-pattern>GetUserInputServlet</url-pattern>
   </servlet-mapping>

This means that whenever you go to URL GetUserInputServlet, the control will be transferred to servlet named GetUserInputServlet.

score 1 · Answer 2 · answered May 23 '17 at 02:46

In from action you need to add only servlet name and in input type name must be same in both place Example In html

In servlet

String abc=request.getparameter("abc");

And if do not won't to used web.xml than you can also used annotations in servlet before servlet class name like

@webservlet

Getting user input from HTML to Java servlet using GlassFish

2 Answers2