(Author: 群 科技 松))
⊙ anastomosis J2EE is a key point
One advantage of J2EE technology is to have portability through the application he developed. To create a cross-platform application with J2EE technology as a background, program developers need to write components of applications in accordance with J2EE specifications, while also need to test them carefully. Through such a process, you can confirm that the written application will be available in a variety of Application Server certified by J2EE technology without concern.
Establishing J2EE applications to make program developers have several advantages, such as one but you are proficient in several simple APIs and application-related settings, then you can easily apply these techniques to build a bigger and more functions. Bar J2EE application. You can pack your original program-based Application Model, which can save a huge fees than the existing applications. In addition, through J2EE technology, many applications can also be managed, just like resources, transactions, system security, certification, information, sustainable storage, name and directory service, etc., which can make you More focused on the issue of Business Process, and some low-order program details are left to the J2EE system architecture.
If you are an IT manager, or a technical appler, you want to bring your organization to the J2EE platform, then you should know what J2EE technology contains what is included, his architecture, and use him to build a component. The basic role of the program developer, so you can know which aspects you can apply. Some related topics in SEMINARs in SEM-345 (Java 2 Platform, Ent Erprise Edition: Technology Overview Seminar). Through two days of seminar, you can have a wide range of J2EE technology overview. The person who participates in the J2EE architecture and his meaning in the industry, and it is also possible to know that the J2EE architecture technology and how J2EE technology is applied to solve some problems in real life.
⊙ A short J2EE architecture and technology J2EE is not just a Java technology platform, he is also a complete business development philosophy, the J2EE system contains four important parts
1. J2EE Platform Specifications J2EE Platform Specifications list many of the J2EE platforms that the APIS and platform developers must support, at least some of the included parts needed.
2. The actual part of the reference example is a free and useful component, which can be used to manipulate the J2EE server platform to test whether J2EE components have an J2EE requirement, he can be used to show the J2EE platform It can also be treated as a prototype of development.
3. Test of a set of compatible suits This set of suits allows the platform to provide vendors to test whether the J2EE platform they live completely matches J2EE specifications.
4. Design Blueprint Design Blueprint is the best practice assistant, he can simplify some of the works of J2EE technology solutions to do, such as expansion, and availability, etc. J2EE Blueprint requires Pattern, Examples, and Files when disclosed, so that you can help designers and developers build their applications on the J2EE technology background.
If you want to match the J2EE standard, you must establish a component-based application, while the J2EE architecture contains three main parts:
a. Components contains presentations and corporate process logic. b. Containers provides the content management required for components. C. Connectors provides pipelines with the database interior of the company. Therefore, the J2EE application seizes a variety of components according to the functional surface, and you can install different application components on the same or different servers to form a J2EE application. The application is installed in accordance with the position where the J2EE multi-layer architecture environment is located. The location of the class may be a client tier, which may be web tier, or Business Tier, or may be an Enterprise Information System, as shown below.
----------- -------------------------------- ---------- | Client Tier | | Web Tier Business Tier | | Eis Tier | ------------- | ------- ---- ------------- | ---------- | || (Presentation (Business || Data || (Web Browser) | | Logic Logic) | | Sourcees | ------------- -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ------ ---------- Middle Application Tier J2EE Architecture
Each layer has a well-defined interface, and it may also contain one or a variety of technical application components.
1. Client Tier Client Tier is responsible for displaying information while collecting the input of the end user (end user). J2EE technology supports several forms of client display methods, like HypertextMarkup Language (HTML) Client, Applet, Extensible Markup Language (XML) file, of course, also contains independent clients with Java as technical background.
2. Web Tier's class is responsible for generating a representation logic, also receives information entered by HTML, Applet, XML Client, while generating an appropriate response to the user. You can do this on the Web Server through Java Servlets technology, or JavaServer Page (JSP) technology. JSP Page allows you to connect your web to other components inside the enterprise. Of course, this layer can also simply generate dynamic web pages, as the XML file is generated. XML makes this layer with cross-platform capabilities, through standard data formats, allow this layer to exchange information between different platforms in different platforms in Java as a technical background.
3. Business Tier This layer is implemented through Enterprise JavaBean (EJB) technology, and the architecture design of EJB can focus on establishing a business process to simplify the entire development process, rather than let developers waste time. On other trivial things. The ejb structure also allows you to call other applications. While the session bean supports the logical flow of the Server, the Entity Bean supports the regular saving of the information. Therefore, the session bean is like the Client as the same relationship with Server. The logic of the application can be executed on an Application Server so that Client can be very streamlined, and this program logic can also be reused. 4. EIS Tier's layer handles the internal information system within the company, and he also includes basic systems within the enterprise, such as Enterprise Resource Planning (ERP), host transaction processing, database system, and other private information systems, etc. . This is actually the so-called "Wrap and Embrace", just like J2EE technology to make existing Enterprise Application to capture the contents of the associated database.
⊙ architecture consideration
It is to know that there are many important factors that consider the architecture of the J2EE application and development, there is a need for consideration. What do you need to do if the application needs to do? Therefore, when we start architectural applications or avoid excessive design, then use the correct technology to become extremely important. For example, an application that uses EJB-based applications is likely to use Java technology because we need to use JSP and JDBC technology. It is important to understand the advantages of each technology, and we also have to weigh different technologies to create a J2EE application, just like thinking about using a web base solution or non-web base solution. Do more analysis and decisions about transaction management, safety management, and deployment components, will help an application design. Don't forget that the J2EE blueprint also shows the best J2EE application examples, which can help you generate your own application architecture. Designers and senior developers need to reference J2EE technology, and weigh these decisions, in addition, there are also shortcuts to learn how to make J2EE applications to expand. So they also need to learn how to make an application with flexible, efficiency, security, and easy management, or learning-related knowledge.
⊙ Basic development role using J2EE technology
J2EE's standard requires a very clear zone, which is intervals the lack of landscape and commercial logic in Application Server. Such a module produces two basic J2EE applications development roles, one is the development of the web component, and the other is the development of business components. The following figure forms the location of these roles in the multi-layer architecture in J2EE.
--------------- --------------- | Web | Business | | Component | | | Developer | Developer | --------------- | ----------- | ----------- | ------------------ | Client Host | || Web Server | | | || || | Data Server || 1.javabeans | || 1 .Servlets | | | Server || | 1.enterprise data || 2.html / xml / wml | http || 2.jsp Pages | RMI | 1.ejb session || jdbc | 2.legacy apps || 3.applets ||| || Beans ||| 3.Backend Interface || 4.GUI | HTML || | | | 2. EJB Entity || | 4.Multiple Data || || | | | | || | Sourcees | ------------- | ------------- | ----------- | ----------------------------------- -------- D Eveloper Roles ⊙Web Component Developers
The developer of the web component on the J2EE platform needs to write an application that can perform on the web. He can be a JSP, or a web-based Applets and servlet, these technologies are to show HTML in the Client side. Web page. Therefore, the developers of the web component need to understand the related technologies of JSP, Servlet, Web-Based, and Web, such as HTML or CGI scripts, and more.
⊙Business Component Developers
