Introduction to Java EE prerequisites

1 , Java is what

TheJava 2 platform Enterprise Edition is a software platform that is ideal for creating server-side large application software and service systems. Java suitable for the development of large-scale business systems, this level of system distribution and running on multiple computers, the interaction between each other unusually frequent. the Java EE platform provides interfaces and standard services to achieve this capability.

2, what's the effect?

used to implement distributed computing. API , and a collection of services and protocols. The goal is to provide support tools for developers to reduce development complexity, shorten development cycles, and improve system performance.

3, basic understanding 1) Architecture
 2) Three componentsWeb Components: including JSP, Servlet, JSF, etc., run on the server. EJB Component: The Java class used to complete the business logic, running on the server. client components: including Java applications, applets, etc., running on the client.
Three kinds of components is the function module that facilitates the Java EE application, which is usually composed of function code class and related files, and communicates with other components to complete the corresponding level function.
3) Four levels
Customer Tier

Client: The portion of the presentation layer that interacts with the user.

server-side: Java Application Server, responsible for deployment Web Components and EJB components that provide basic services for these components, while allowing clients to access these components

Presentation Layer

JSP: is a "view" component in the Java EE, and a text file for dynamic Web pages based on client requests.

Include, HTML tags, jsp tags, java code

Servlet: Is a Java class that interacts with a Web customer using the HTTP protocol-based request/corresponding pattern type

Business Logic Layer

EJB: Is a Java component that implements distributed business logic.

Role: To provide customers with a distributed and deployable business logic service, with well-defined interfaces that can be reused between application servers, and executed within the container that provides management and control services.

Data layer

The above is the basic understanding of the Java EE, the later content there are many ...

Introduction to Java EE prerequisites