[FIXED] My IDE is not recognizing HTML commands for my servlet

Issue

I am learning how to create a servlet that takes HTML code and makes a program in my browser. This code was supposed to output a simple welcome message in my browser via HTML. However, My eclipse IDE does not recognize any of the HTML commands in this code. It says that the imports are not accessible and that the HTTP variables can't be resolved to a type. I'm using tomcat version 10.0.12 and Java 13 for the code (I also have java 16 but eclipse only gave me the option to use 13). I've tried uninstalling and reinstalling Tomcat several times and adding servlet-api.jar but none of those changed a thing. I know there's an extra step I'm missing but I can't figure out what it is?

import jakarta.servlet.*;
import jakarta.servlet.http.*;
import java.io.*;

public class WelcomeServlet extends HttpServlet {   
@Override
protected void doGet( HttpServletRequest request, 
                   HttpServletResponse response ) throws ServletException, IOException  {

   response.setContentType( "text/html" );
   PrintWriter out = response.getWriter(); 
   out.println( "<title>Welcome to Servlets!</title>" ); 
   {...}
   out.println( "</html>" );
   out.close();  // close stream to complete the page
   } 
}

Solution

You've messed up your imports. It sounds like you're following a tutorial that's 20+ years old, a lot of what you're doing is extremely outdated. The web is a fairly fast moving environment; I strenously advise against using such old tutorials.

The correct import is import javax.servlet.http.HttpServletRequest;.

Some notes on what you're doing that are bad ideas:

• Star imports aren't advised; it's a bit too easy to get confused about where things live or which type(s) you are fetching from where. Your IDE manages your imports for you; let it.

• You don't want to write HTML inside strings inside your code. Use a templating engine such as Freemarker, Velocity, Thymeleaf, or Google Closure Templates. Alternatively, write static HTML with a ton of javascript (probably with a client-side javascript-based framework) and write your server as an API that doesn't 'answer' in terms of HTML files; it answers in terms of some structured data format such as JSON. Your static (as in, unchanging; any file-serving HTTP service can provide them) HTML+CSS+Javascript does the job of calling your API to get this structured data, and then your HTML+CSS+JavaScript does the job of rendering it into HTML.

• Raw servlets is outdated; the API is extremely old and it shows, for example, you can't even use a simple for-each loop to iterate over all parameter names, because the API returns the obsolete Enumeration instead of the more modern Iterator or even Stream. You neither get the benefit of storing intermediate state in fields (because you aren't guaranteed one instance per invocation), but you also don't get to just dump it all in static fields either (as the spec doesn't guarantee that there'll only ever be one instance) - the worst of both worlds. Look into JAX-RS, Jersey, Dropwizard, sparkjava, or other such frameworks.

Answered By - rzwitserloot
Answer Checked By - Dawn Plyler (JavaFixing Volunteer)