Tomcat - Context path

The context path is a key element of a web application. It's also used for a virtual host. Virtual hosting can be defi ned as a method through which you can host multiple domain names on the same web server or a single IP.

The context path is also used to defi ne the URL mapping for the .war fi les.

Many people ask why we need the context path. Instead, can we deploy the application on one root directory? The answer is, by defi ning the context path, we minimize the load on the server. When the server gets the request with the URL, it will check the server.xml or context path for the defi ned URL. If it's found, then the URL will be served from here, otherwise the server has to search all the deployed WAR fi les. Hence, the context path reduces the CPU cycle.

The second important advantage is, it gives us freedom to customize the application based on our requirement, such as logging, appBase, DB connection, and so on.

Let's consider a scenario for a large enterprise where a single application needs to be deployed on 100 Tomcat servers. Now it's impossible to deploy the application on every server, and so, in that case Common NAS share is used for the application deployment.

Enabling the context path

The context path in Tomcat can be enabled in two ways:

• GUI using the Tomcat Web Application Manager
• Command-line confi guration in server.xml

GUI using the Tomcat Web Application Manager

For enabling the context path in the Tomcat Manager, you have to fi rst log in to the Tomcat Manager app using the URL http://localhost:8080. Then click on Manager App, as shown in the following screenshot:

You can create the context path using the Deploy tab. Click on Browse and select the required WAR fi le. Then click on Deploy. It will take 10 to 15 seconds to deploy the application and you will see a page .


Command-line confi guration in server.xml

Another way of adding the context path in Tomcat 7 is by editing server.xml. But, you need to have a good understanding of XML. Let's quickly discuss the changes that need to be done on the Tomcat server.


Now, it's time to discuss the parameters defi ned in the context path. The previous screenshot shows the details for the context path.

• path="/sample": It defi nes the path URL for the server request, for example, http://localhost:8080/sample.
• docBase="/opt/": It defi nes the document root for the context path. In simple language, this parameter defi nes the place from where the deployment .war fi le gets picked up.
• reloadable="true": If this parameter is true, then every change done on the WAR fi le will be in effect automatically without a Tomcat recycle.
• swallowOutput="true": If this parameter is set to true, then the output for System.out and System.err will be redirected to the application log.

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