Web Application Archives

If you want to distribute a Web application, you package it in a Web application archive (WAR), which is a JAR similar to the package used for Java class libraries. In addition to Web components, a Web application archive can contain other files including the following:

Server-side utility classes (database beans, shopping carts, and so on). Often these classes conform to the JavaBeans component architecture.

Static Web presentation content (HTML, image, and sound files, and so on)

Client-side classes (applets and utility classes)

A Web application can run from a WAR file or from an unpacked directory laid out in the same format as a WAR.

WAR Directory Structure

The top-level directory of a WAR is the document root of the application. The document root is where JSP pages, client-side classes and archives, and static Web resources are stored.

The document root contains a subdirectory called WEB-INF, which contains the following files and directories:

web.xml - The Web application deployment descriptor

Tag library descriptor files (see Tag Library Descriptors)

classes - A directory that contains server-side classes: servlets, utility classes, and JavaBeans components

lib - A directory that contains JAR archives of libraries (tag libraries and any utility libraries called by server-side classes)

You can also create application-specific subdirectories (that is, package directories) in either the document root or the WEB-INF/classes directory.

Tutorial Example Directory Structure

To facilitate iterative development and keep Web application source separate from compiled files, the source code for the tutorial examples is stored in the following structure under each application directory mywebapp:

build.xml - Ant build file

context.xml - Optional application configuration file

src - Java source of servlets and JavaBeans components

web - JSP pages and HTML pages, images

The Ant build files (build.xml) distributed with the examples contain targets to create an unpacked WAR structure in the build subdirectory of mywebapp, copy and compile files into that directory, and invoke the manager (see Tomcat Web Application Manager) commands via special Ant tasks to install, reload, remove, deploy, and undeploy applications. The tutorial example Ant targets are:

prepare - Creates build directory and WAR subdirectories.

build - Compiles and copies the mywebapp Web application files into the build directory.

install - Notifies Tomcat to install an application (see Installing Web Applications) using the Ant install task.

reload - Notifies Tomcat to reload the application (see Updating Web Applications) using the Ant reload task.

deploy - Notifies Tomcat to deploy the application (see Deploying Web Applications) using the Ant deploy task.

undeploy - Notifies Tomcat to undeploy the application (see Undeploying Web Applications) using the Ant undeploy task.

remove - Notifies Tomcat to remove the application (see Removing Web Applications) using the Ant remove task.

Creating a WAR

With the JAR tool distributed with the J2SE SDK. You simply execute the following command in the build directory of a tutorial example:

  jar cvf mywebapp.war .

With the Ant war task

Both of these methods require you to have created a Web application deployment descriptor.