.war vs .ear file
The .war file is utilized for web applications (capabilities like servlets, JSPs, HTML, CSS, JS), and is executed in a servlet container like Tomcat. On the other hand, the .ear file is designed for enterprise applications, which combines .war files and EJBs, along with other Java EE models to be deployed on a full-scale application server like WildFly or WebSphere.
Decide on:
- .war for simpler, web-centric applications.
- .ear for complex systems with several modules (Web, EJB, etc.)
Illustration:
- A non-complex web app:
myapp.war - An all-encompassing enterprise application with web and EJB modules:
myenterpriseapp.ear |-- myweb.war |-- myejb.jar //# Enterprise architect's joy ride.
The Role of .war and .ear in Deployment
.war files allow developers to pack and install web applications directly. This holds significant value when the application is purely web-oriented without dealing with intense business logic or transactions.
On the other hand, .ear files cater to a broader concept in the Java Enterprise Edition (Java EE) world. They are devised to handle large-scale, multi-modular applications. Combining .war modules (with the web layer) and .jar modules (including EJBs and other business logic), you establish an integrated structure. This balanced approach is crucial to ensure uniform configuration, resource-sharing, and module management.
Understanding Container Roles
Whether you use .war or .ear files impacts deployment significantly. The .war is positioned within a Web container, tasked with managing HTTP requests and delivering web content. .ear files are deployed to both Web and EJB containers, with the latter controlling transactions, security, and RPCs.
When dealing with complicated enterprise scenarios encompassing security roles, transaction management, and numerous entry points, an .ear file emerges as the robust solution providing the necessary infrastructure via deployment descriptors.
Dive into Directory Structures
A key feature of the .war file structure is the WEB-INF folder. This works as the core for web application configuration, accommodating the web.xml file and various other configuration files and libraries needed for smooth application execution.
Contrastingly, .ear files include an APP-INF directory for accommodating application-wide libraries and configuration files. This enables centralized control for enterprises juggling multiple modules.
Security Measures and Code Integrity
Security is an utmost priority for enterprise applications. EAR files outline security roles and URL mapping configurations for comprehensive application access control. Furthermore, WAR files can be digitally signed to guarantee code authenticity and integrity, ensuring the code originates from a trusted source and remains untampered.
Handling Archive Files
Developers can leverage tools like JAR utility or various ZIP utilities to streamline .jar, .war and .ear file creation and extraction. Efficiently managing these Java archive files is critical to software lifecycle management.
Scalability: From Simplicity to Complexity
For straightforward situations, a single .war file might suffice. But as applications grow more complex and begin to incorporate various components like EJBs, JMS, etc., the .ear file becomes a necessity. This encapsulation of web and business components allows enterprises to scale up and manage their applications' growth effectively.
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