Trying to setup tomcat to use servlets

Question

I'm following instructions found in Java All in one for Dummies 3rd edition

I downloaded tomcat and followed all the steps for setting it up, step 6 says. "Modify the web.xml file to enable the invoker servlet" It says to find the lines of code for the invoker and then comment them. I am currently in the web.xml file and searched for invoke, but nothing came up... should I code the invoker in myself? or umcomment a different line?(this book is 4 years old and may be outdated) Or just not change anything at all?

as not everybody may have this book you should quote the web.xml file. Which version of Tomcat do you use ? What is there besides the web.xml ? Give us more details — Marged, Jun 15 '15 at 20:26
Looks like you're reading a very old book. Nowadays, you should use `@WebServlet` annotation rather than playing with the web.xml file. — Luiggi Mendoza, Jun 15 '15 at 20:32

score 2 · Accepted Answer · answered Jun 15 '15 at 21:02

I've just take a quick look up to the book and on page 407, there are the lines that you have to decomment or/else if not exist, add.

From the book;

<!--
     <servlet>
         <servlet-name>invoker</servlet-name>
         <servlet-class>
           org.apache.catalina.servlets.InvokerServlet
         </servlet-class>
         <init-param>
             <param-name>debug</param-name>
             <param-value>0</param-value>
         </init-param>
         <load-on-startup>2</load-on-startup>
     </servlet>
 -->

Anything located in between the "" will be interpreted as comments, which won't have any functional effect.

What you have to do is, to delete/remove the "" parts of this. Which is;

     <servlet>
         <servlet-name>invoker</servlet-name>
         <servlet-class>
           org.apache.catalina.servlets.InvokerServlet
         </servlet-class>
         <init-param>
             <param-name>debug</param-name>
             <param-value>0</param-value>
         </init-param>
         <load-on-startup>2</load-on-startup>
     </servlet>

As it is written on the book, on the same "web.xml" file, you also have to find the lines below;

<!--
    <servlet-mapping>
        <servlet-name>invoker</servlet-name>
        <url-pattern>/servlet/*</url-pattern>
    </servlet-mapping
 -->

And commenting out them to make them visible to the tomcat, as removing the same comment lines, like below;

<servlet-mapping>
    <servlet-name>invoker</servlet-name>
    <url-pattern>/servlet/*</url-pattern>
</servlet-mapping

Remember, you all have to execute these on the web.xml file.

And one more thing, If you cannot find these two parts, you can simply add these as below;

Just add them to the web.xml file as is;

     <servlet>
         <servlet-name>invoker</servlet-name>
         <servlet-class>
           org.apache.catalina.servlets.InvokerServlet
         </servlet-class>
         <init-param>
             <param-name>debug</param-name>
             <param-value>0</param-value>
         </init-param>
         <load-on-startup>2</load-on-startup>
     </servlet>


    <servlet-mapping>
        <servlet-name>invoker</servlet-name>
        <url-pattern>/servlet/*</url-pattern>
    </servlet-mapping

@user3527058 I'm glad for that if it helped a bit. – Levent Divilioglu Jun 15 '15 at 21:13 — Levent Divilioglu, Jun 15 '15 at 21:13

SSH · Answer 2 · 2015-06-15T20:35:03.163

Just for your reference, this is my web.xml

<?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" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" 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>IPNListener</display-name>
 <servlet>
        <servlet-name>PaypalListenerServlet</servlet-name> //your servlet name
        <servlet-class>com.paypal.ipn.PaypalListenerServlet</servlet-class>// your actual java class
    </servlet>
    <servlet-mapping>
        <servlet-name>PaypalListenerServlet</servlet-name>
        <url-pattern>/*</url-pattern>//pattern of your calling url
    </servlet-mapping>
</web-app>

Further you can give a look here for understanding of this web.xml file

Trying to setup tomcat to use servlets

2 Answers2