Today, I saw an article on IBM's website that mentioned the functions of each role in J2EE development, I feel very interesting to knowing J2EE, so I record it.
The J2EE specification delegates responsibilities to multiple development roles: Component Provider, Application Assembler, Deployer (Deployer), and System Administrator. (In many companies, the role of the component provider and component assembly is integrated, the role of deployers and system administrators is integrated together.) Master the J2EE role before you really understand the JDI role in J2EE. It is very important.
Component provider
This role is responsible for creating J2EE components, the J2EE component can be a web application, an enterprise-level JavaBean (EJB) component, or an application client (such as Swing GUI client applications). Component providers include: HTML designers, document programmers, and other developers. Most J2EE developers spend considerable time on the role of component providers.
Application assembly
This role is bundled with a plurality of J2EE modules into one other, and can be deployed as a whole: Enterprise Archive (EAR) file. Application assembly is to select components to distinguish between interacts between them, configure their security and transaction properties, and package applications into the EAR file. Many IDEs, such as WebSphere® Studio, IDEA, JBUILDER, WebLogic Workshop, and other IDEs, can help the application assemblers configure an EAR file in interactive.
Deployer (Deployer)
This role is responsible for deploying, which means installing the EAR into the J2EE container (application server), then configures resources (eg, database connection pool), binding the resources required by the application to specific resources in the application server, and start the application program.
System administrator
This role is responsible for ensuring that resources needed by the container can be used for containers.
Role Batters have an enterprise application that contains a web application, as well as EJB components responsible for business logic and persistence. There are many components vendors developing this app, but in many cases, you can assume all your duties. Components can include data transfer objects (a JAR file), EJB interface (another JAR file), EJB implement itself (another JAR file), and user interface components - servlet, JSP, HTML pages, and other static web content. The user interface component is further packaged into a web application, which contains the servlet class, JSP files, static content, and JAR (including EJB interfaces) of other required components.
This sounds like it is too much to use, almost exceeded the scope of people, especially when considering how many JAR files that need to build a typical web application. However, it is important to recognize that it must manage dependencies here. Interfaces and transfer objects are web applications and EJB implementations that can rely on, but the direction of dependence should be the same; also avoiding loop dependence. J2EE components (such as WAR files and EJB JAR files) must declare their dependence on their deployment units. Application assemblers are responsible for inclusion of dependencies in the web application and package them as a whole into a single enterprise application. The tool is here helpful. IDE can help create project structures that reflect modules and JAR dependencies, allowing you to specify or exclude modules.
The deployment personnel are responsible for ensuring the resources required to exist in the deployment environment and bind components to the available resources of the platform. For example, an external EJB reference in a web application (EJB-REF in the deployment descriptor) is the EJB component that is bound to actual deployment at this time - and is immediately bound.
