[java] Deploying my application at the root in Tomcat

I have the war file of my application. I need to deploy this at the root level. The current URL is http://localhost:8080/war_name/application_name.

on tomcat v.7 (vanilla installation)

in your conf/server.xml add the following bit towards the end of the file, just before the </Host> closing tag:

<Context path="" docBase="app_name">
    <!-- Default set of monitored resources -->
    <WatchedResource>WEB-INF/web.xml</WatchedResource>
</Context>

Note that docBase attribute. It's the important bit. You either make sure you've deployed app_name before you change your root web app, or just copy your unpacked webapp (app_name) into your tomcat's webapps folder. Startup, visit root, see your app_name there!

In tomcat 7 with these changes, i'm able to access myAPP at / and ROOT at /ROOT

<Context path="" docBase="myAPP">
     <!-- Default set of monitored resources -->
     <WatchedResource>WEB-INF/web.xml</WatchedResource>
</Context>
<Context path="ROOT" docBase="ROOT">
     <!-- Default set of monitored resources -->
     <WatchedResource>WEB-INF/web.xml</WatchedResource>
</Context>

Add above to the <Host> section in server.xml

Adding on to @Rob Hruska's sol, this setting in server.xml inside section works:

<Context path="" docBase="gateway" reloadable="true" override="true"> </Context>

Note: override="true" might be required in some cases.

Remove $CATALINA_HOME/webapps/ROOT. Update $CATALINA_HOME/conf/server.xml, make sure that Host element look like the following text:

<Host name="localhost"  appBase="webapps"
      unpackWARs="true" autoDeploy="false" deployOnStartup="false">
  <Context path="" docBase="myApp"></Context>

It works with Tomcat 8. autoDeploy and deployOnStartup need to set to false to prevent tomcat from deploying myApp twice.

Adding to @Dima's answer, if you're using maven to build your package, you can tell it to set your WAR file name to ROOT in pom.xml:

<build>
    <finalName>ROOT</finalName>
</build>

By default, tomcat will deploy ROOT.war webapp into root context (/).

In my server I am using this and root autodeploy works just fine:

   <Host name="mysite" autoDeploy="true" appBase="webapps" unpackWARs="true" deployOnStartup="true">
        <Alias>www.mysite.com</Alias>
        <Valve className="org.apache.catalina.valves.RemoteIpValve" protocolHeader="X-Forwarded-Proto"/>
        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
           prefix="mysite_access_log." suffix=".txt"
           pattern="%h %l %u %t &quot;%r&quot; %s %b"/>
        <Context path="/mysite" docBase="mysite" reloadable="true"/>
    </Host>

I know that my answer is kind of overlapping with some of the other answer, but this is a complete solution that has some advantages. This works on Tomcat 8:

1. The main application is served from the root
2. The deployment of war files through the web interface is maintained.
3. The main application will run on port 80 while only the admins have access to the managment folders (I realize that *nix systems require superuser for binding to 80, but on windows this is not an issue).

This means that you only have to restart the tomcat once, and after updated war files can be deployed without a problem.

Step 1: In the server.xml file, find the connector entry and replace it with:

<Connector 
    port="8080"
    protocol="HTTP/1.1"
    connectionTimeout="20000"
    redirectPort="8443" />

<Connector
    port="80"
    protocol="HTTP/1.1"
    connectionTimeout="20000"
    redirectPort="8443" />

Step 2: Define contexts within the <Host ...> tag:

<Context path="/" docBase="CAS">
    <WatchedResource>WEB-INF/web.xml</WatchedResource>
</Context>
<Context path="/ROOT" docBase="ROOT">
    <WatchedResource>WEB-INF/web.xml</WatchedResource>
</Context>
<Context path="/manager" docBase="manager" privileged="true">
    <WatchedResource>WEB-INF/web.xml</WatchedResource>
</Context>
<Context path="/host-manager" docBase="host-manager" privileged="true">
    <WatchedResource>WEB-INF/web.xml</WatchedResource>
</Context>

Note that I addressed all apps in the webapp folder. The first effectively switch the root and the main app from position. ROOT is now on http://example.com/ROOT and the the main application is on http://example.com/. The webapps that are password protected require the privileged="true" attribute.

When you deploy a CAS.war file that matches with the root (<Context path="/" docBase="CAS"> you have to reload that one in the admin panel as it does not refresh with the deployment.

Do not include the <Context path="/CAS" docBase="CAS"> in your contexts as it disables the manager option to deploy war files. This means that you can access the app in two ways: http://example.com/ and http://example.com/APP/

Step 3: In order to prevent unwanted access to the root and manager folder, add a valve to those context tags like this:

<Context path="/manager" docBase="manager" privileged="true">
    <WatchedResource>WEB-INF/web.xml</WatchedResource>
    <Valve className="org.apache.catalina.valves.RemoteAddrValve"
        addConnectorPort="true"
        allow="143\.21\.2\.\d+;8080|127\.0\.0\.1;8080|::1;8080|0:0:0:0:0:0:0:1;8080"/>
</Context>

This essentially limits access to the admin web app folder to people from my own domain (fake IP address) and localhost when they use the default port 8080 and maintains the ability to dynamically deploy the war files through the web interface.

If you want to use this for multiple apps that are using different IP addresses, you can add the IP address to the connector (address="143.21.2.1").

If you want to run multiple web apps from the root, you can duplicate the Service tag (use a different name for the second) and change the docbase of the <Context path="/" docBase="CAS"> to for example <Context path="/" docBase="ICR">.

The fastest way.

1. Make sure you don't have ROOT app deployed, undeploy if you have one

2. Rename your war to ROOT.war, deploy, thats all, no configuration changes needed

open tomact manager url :- http://localhost:8080/manager/html/
then in applications you see a application having path as "/" is deployed
simply Undeploy this.
Rename your application's war file as ROOT.war and just place at path :-
C:\Program Files\Apache Software Foundation\Tomcat 8.5\webapps
start your Tomcat No extra configuration needed.
Now we can see our application home page or configured url at http://localhost:8080