Java EE Overview (2)

Java EE an application client runs on the client machine, enabling the user to handle tasks that require a richer user interface than the markup language can provide. A graphical user interface (GUI) that is typically built with swing or the Abstract Window Toolkit (AWT) API, but a command-line interface is certainly possible.
The application client directly accesses the enterprise bean running in the business layer. However, if an application requires authorization, a Java EE application client can open an HTTP connection to establish communication with a servlet running in the Web tier.

4, JavaBeans component Architecture Server layer and customer layer can also be included in JavaBean Component Architecture (JavaBeans component) The underlying component manages the flow of data between an application client or applet and the components running on the Java EE server, and between the server-side components and the database. The JavaBeans component is not considered a Java EE component in the Java EE specification.

The JavaBeans component has instance variables and the get and set methods used to access the data in the instance variable. The JavaBeans component for this purpose is fairly simple to design and execute, but it must comply with the commands and design conventions of the JavaBeans component architecture.

5, Java-EE server communication Figure 1-2 shows the customer layer composed of a variety of ways. The client can communicate directly with the business layer running in the Java EE server. If you are a client running in a browser, you can also do this by running a JSP page in the Web layer and a servlet.
Your Java EE application is a thin client or a fat client. To make such a decision, you should understand that the fat client is going to leave the feature on the client so that it is closer to the user, while the thin client is to deliver the functionality to the server as much as possible. It is easier to distribute, deploy, and manage applications when more functionality is handled by the server, while leaving more functionality on the client may be a wise choice for experienced users.

Figure 1-2 The Web component of server communications Java can be either a servlet or a JSP page. Servlets is a Java programming language class that can dynamically process requests and respond. A JSP page is a text-based document that executes as a servlet, but it makes it easier to create static content.
static HTML pages and applets are bound to Web components when the application is assembled, but they are not considered Web components by the Java EE specification. Server-side functional classes can also be bound to Web components, and, like HTML pages, they are not considered Web components by the Java EE specification.
As shown in Figure 1-3, as with the customer layer, the Web layer can also contain a JavaBeans component to manage user input and send input to the enterprise bean running in the business layer for processing.

Figure 1-3 The Web layer and the Java EE Application Commercial Code, which represents the appropriate logic for specific business areas such as banking, retailing, and finance. It is handled by the enterprise bean running in the business layer. Figure 1-4 shows how a enterprise bean accepts data from the client, processes it (if needed), and sends it to the enterprise Information System layer for storage. A enterprise bean can also fetch data from the memory, process it (if needed), and send it to the client application.

Figure 1-4 Business layer and EIS layer