Apache – How to create “Aliases” in Apache Tomcat

In order to use mod_rewrite you can type the following command in the terminal:

sudo a2enmod rewrite

Restart apache2 after

sudo /etc/init.d/apache2 restart

or

sudo service apache2 restart

or as per new unified System Control Way

sudo systemctl restart apache2

Then, if you'd like, you can use the following .htaccess file.

<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteBase /
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule . /index.php [L]
</IfModule>

The above .htaccess file (if placed in your DocumentRoot) will redirect all traffic to an index.php file in the DocumentRoot unless the file exists.

So, let's say you have the following directory structure and httpdocs is the DocumentRoot

httpdocs/
    .htaccess
    index.php
    images/
        hello.png
    js/
        jquery.js
    css/
        style.css
includes/
    app/
        app.php

Any file that exists in httpdocs will be served to the requester using the .htaccess shown above, however, everything else will be redirected to httpdocs/index.php. Your application files in includes/app will not be accessible.

You're actually confusing the notions of "debugging" and hot deploy. You can configure Tomcat for debug mode, and then remotely debug your application running inside tomcat such that when you add a break point in your code, the debugger will jump to that breakpoint and halt execution.

What you actually need there is having the possibility to hotdeploy an application. With tomcat, if you modify the .java files and then copy them to the working directory of tomcat, you'll get exactly what you want, namely the ability to change something in a class and have the running tomcat-deployed application take it into account without redeploying the whole application. You can automatize this by configuring your tomcat application context (either in the tomcat server.xml file or in a project specific context.xml file) for your application to have as working directory the directory where your project code gets compiled.

here's an actual example:

Let's say you have a maven project in the directory c:\myProject. You'd have source files in the c:\myProject\src, and then when compiling it you'd get the war file and an exploded directory of the war file content in the c:\myProject\target\myProject.war and respectively c:\myProject\target\myProject. Now, if you configure your tomcat such that for the myProject tomcat context, youd have the working directory configured as c:\myProject\target\myProject, then each time you modify a .java file, the .class corresponding file will be updated in the target (and now also working) dir, and tomcat will take it into account.

I've actually used such a setup to develop with tomcat, but it's not the best. First off tomcat will hotdeploy only certain modifications, such as when you modify something in the body of an existing method. Other modifications will not be taken into account, such as adding a new method - for this you have to do a full redeploy to have it taken into account.

A far better solution is to use maven with the maven jetty plugin. This thing really works as you want: any modification you do to a class of jsp file will me immediately taken into account, and visible in the running app inside jetty.