Summary The Java 2 Enterprise Version (J2EE) platform consists of four main parts: specification, reference implementation, compatibility test packets, and BluePrints programs. Blueprints describes the best practice and design guidelines for a distributed component system. This article describes a J2EE development methodology composed of eight steps, which is based on the Rational Unified Process and BluePrints application examples. Through this article, you will be able to better understand many of the important topics of the J2EE system, and you can apply these knowledge to expand and modify this simple methodology to address a variety of specific business issues. In the business, we use Java 2 Enterprise Version (J2EE) to solve business problems, develop business software, or provide services to other commercial projects. If a company should use multi-level system to create an e-commerce website, in its entire development cycle, it usually needs managers, system builders, designers, programmers, testers and database experts to participate. In order to make different parts work effectively, we usually need a software development process. A classic development process includes a waterfall model, fast application development (RAD) and final programming. In this article, we will focus on a popular software design process - tarional unified process (RUP). RUP provides a special way to assign tasks for different roles. Its goal is to ensure high quality software in a predictable progress and budget to consist of high quality software to comply with users. I use RUP for J2EE development. There are three reasons. First, the RUP is based on the system; before submitting resources for all-round development, it first develops an executable system prototype. Second, RUP is iterative and is based on components. The basics of this system generally include an architecture that can easily increase the components by iteration, thereby customizing and expanding a system on the basis of other parts of the system. third. RUP uses an industrial standard language -uml that can display the system's system and components to visualize. RUP has 4 different development phases: Inception, ElaBoral, Construction, and Transition. This article will introduce eight basic steps developed by J2EE from a technology point of view, which is maintained by the system. 1. Demand Analysis Demand Analysis is used to describe the system and should not do anything, so that developers and users can create an initialized business relationship. You can use the business concept, the terms, block diagrams, or other methods of this field write functional needs, rather than functionality, such as performance and transactions, can be written in additional demand documents. You can create a high-level UI model with text or html, which way you have to see you in the project. A typical e-commerce system. ViewOrDER diagram illustrates a user logged in to the system via the Web to view the list of orders, and you can click to see the details of each order. AddLineItems descriptions are users to browse the product catalog, select the product of interest, and join them to the purchase order. II, object-oriented analysis and analysis. Problem domain model: class, object and interaction. Your analysis should be separated from any technique or implementation, but should include an ideal model. Object analysis can help you understand problems and get knowledge in terms of problems. You have to maintain a model of a pure field that does not include the details of the technology, which is because the change in business processes is much slower than information technology.
The above two-step-demand analysis and object-oriented analysis are not unique to J2EE, which is common for many object-oriented methodology. A high-level object analysis model, which is an example of a pet store. It illustrates the main concepts determined by the needs analysis of the needs analysis. We model these concepts into the object and determine their relationship. The result of demand and object analysis is an entry point for the J2EE system development. To develop a system, you can choose a vertical part - is usually a key part, such as an object model in the order field - to make object design, implementation, testing, and development. (A vertical part is a RUP concept, a small part of the system. The start point is a subset of Use Case. A vertical part of the implementation will generate a full-featured mini system, including all layers, such as user interface Layer JavaServer Pages (JSPS), medium-level commercial objects, such as Enterprise JavaBeans (EJBS), and a background database). You can apply experienced from the prototype to the domain object, and these awareness as a design guideline in the object design phase. III, the system specification passes the previous two steps, and the problems and needs in the business areas should be clarified. Now we will focus on technical strategies and systems. A system is a blueprint for each part to define the entire system: structure, interface and communication technology. We can further divide a system into a business and application system. Enterprise system system system system covers hardware and software architectures, network topologies, development, testing and production environment. These reflect a long-term investment of a company. Before development, you need to assess existing software and hardware architectures. If it doesn't fully support J2EE, you may join new components and upgrade your existing system. You need to completely evaluate hardware, including computers, routers, switches, and network topologies, because they all affect the performance and stability of the system. Multi-storey enterprise systems have the following main components: .Web browser client, it may be behind the client company's firewall. HTTP server, which is usually in the DMZ area .Web container host provides performance or business logic components. Application container Provide business logic components. The system system type used by relational database management system (RDBMS) and database provides data and data logic is based on your needs of security, performance, reliability and your company's financial situation. When you require a very low, you can even use a second-hand computer and a telephone line. On the Internet, there are many Open source operating systems, web servers, application servers, and database management systems. The cost of these systems may only have a few hundred dollars, of course, it may be troublesome. High-end customers, such as many Wall Street financial institutions, they need a system that supports secure, high throughput and cope with non-expected network communication. In this case, you usually need an N layer system with a web server and application server, and set to a cluster to achieve fault tolerance. You also need to evaluate software architecture, including web servers, security management software, application servers, domain name management servers, database management systems, and third-party software components. If you haven't purchased your application server, then in the evaluation process, choose one J2EE's manufacturer will be an important part. I want to remind you that different manufacturers have great achievements of J2EE, and some support only the old J2EE version. In addition, some web containers or application containers may be more faster than others. In addition to achieving J2EE specifications, many manufacturers also sell components or architectures for J2EE systems. It is also important to choose a stable J2EE manufacturer because it can be supported for a long time.
You can usually purchase or develop in the system system level, including:. Transaction processing. Internationalization and localization. Cluster and object distribution. Session management. Application performance measurements and descriptions. Message. Workflow management. Entrance and personalized management. Layer to layer communication protocol. Safety and firewall application system application systems are built on the enterprise system system, referring to a special project or application. After the architecture is completed, the system establishes personnel will study how to establish a specialized application. If your business system just supports an old J2EE version, you may need to upgrade your system first. If you don't upgrade due to budget or time relationship, you must work under the technical limitations of the old version. It is important to establish an enterprise-class reusable component. The ultimate goal is to meet the needs of our customers. An architect is not a designer; the system and design are two different things. The scope of an application system is the main structure of the system, its architecture and you can add components to the architecture of the components above. The system is mainly related to the non-functional aspects of implementation, and the design is related to the commercial use cases, and use cases refers to the part of your application to convert the domain object model as a technical object model. The application system is the structure of the project, a specialized application. The decisions you usually make when the application architecture is developed, including:. The functional division between the layers. Model domain object. Previous systems need to be saved. Software components purchased. Components that need to be created. How to integrate third-party components Interface domain objects in Figure 3 explain how you do model domain objects. For current Java technology, you can distribute the domain objects in several places, including the continuation of the developer management, placed in a Web container, as an EJB, or in the RDBMS host as the stored procedure. In a pet store's design, we design the order object as an entity bean, a detail object and a data access object, as shown in Figure 5 and Figure 6 later. When you see this, you will recognize the importance of its system. You can think about why a domain object in the analysis model is mapped to so many objects, and what will happen if you change the design. You may have heard the benefits of EJB, but it is important to pay attention to the performance of different manufacturers. When new technologies come, you need to do research before you put it in a system, do some tests. In fact, the development of the so-called system is to convert vertical blocks of design and implementation domain object models to design other domain objects. In the early days of J2EE, some object-oriented designers attempt to map domain objects into entity beans and transfer them between layers. They have a very good UML block diagram, but the result is a slow system, which is caused by unnecessary network communication. The object analysis directly enters the object design, and there is no system design, and there is no clear understanding of a new technology, which usually causes a project to fail. Deliverable systems Since the J2EE system is a relatively new subject, a deliberable J2EE system is not well defined. In the case of a pet shop, it is difficult to see where the system ends and the design where is designed. The document is checked by a high-level application system, and the Model-View-Controller design mode is discussed and a system overview begins. Low level document is the source code. No UML block diagram. Sun's J2EE Enterprise System Certified delegation part requires all deliverables to use UML. However, here is only a class block diagram, a component block diagram, and some object interaction block diagrams. These are not sufficient for a true J2EE application.
To start, the system specifications and processes require at least the following aspects: one system architecture, used to describe your existing hardware, software, network topology, and other components. An application system documentation, used to describe the main Structure, including all components, USE CASE components, and previous components for the system. A new component design guidelines are used to describe all design policies and system decisions, explain all of these decisions, and explain if What possible results will be selected for other options. These guidelines should contain all important basic decisions to comply with these regulations when designing new components to maintain the integrity of the system system. A work system prototype to assess new technologies; experience from the development and configuration of J2EE applications; establish a system architecture; through measurement performance, scalability to indicate the risk of risk; also prove your method to customers is feasible in you After developing a few J2EE programs and get more experience, the prototype will no longer be so important, then some UML block diagrams and some design policies may be enough. IV, object design under the guidance of system specifications, design can be expanded and adapt to the results of analysis. When the analysis phase, the domain object modeling should be independent of the details of the technology, and the object design is closely related to technical factors, including which type of platform, language, and manufacturers used in the system development phase. In theory, you don't modify business objects unless you must do this in order to maintain their basic properties and behaviors. Under the guidance of the system resolution, a detailed design should be mentioned to all classes, including the necessary implementation properties, their detailed interface and pseudo code or plain text descriptions of the operation. The detailed level of the specification should be achieved as long as the model is combined, all necessary programming information can be obtained. In many automated software production processes, you can generate a framework from the object-oriented block diagram. It should be noted that stub and skeleton usually do not need to be displayed in block diagrams because they are transparent to designers and programmers. I contain them in Figure 6 just to illustrate the basic point of EJB. After you complete the detailed object design, you complete the object-related mapping of the domain object. The reason is that although object-oriented methodology is currently more advanced, but most popular and lasting stores are relational. In addition, a customer's IT architecture has reflected existing investment and commercial RDBMS manufacturers in many ways. Therefore, the domain object model is converted to a relational model or a database table is very important. There are many container management tools, but they cannot replace a good relationship database design. V, achieving a good architecture and detail design, which will be a very clear task. In addition, since we design and implement a vertical part of the system in the system prototype, we will not encounter a lot of troubles in the implementation stage. In many companies, developers are usually prematurely entering the implementation phase, especially when managing them, because of them, do other things, etc. As a result, no longer spend the time to draw a UML block diagram, but test ideas in code development, it takes the week and months. In this case, all system resolutions and design are in the code phase. What is made, usually in a few months will find that development has entered a wrong direction. VI, confirm confirmation includes tests to verify that the system meets the design and meets demand. In the entire development cycle, verification occurs during the development and installation phase. Unit testing, integrated testing and user tolerance test are important topics VII, combined, and configured component assembly and scheme configuration in J2EE development is particularly important. The environment where developed and installed may be completely different. If the EJB is in the system, you need to use the manufacturer's expertise to make a class that generates the container. I also mentioned that the configuration of the web or application components is different for different manufacturers.
You must also consider whether the system you want to configure has any of the code specified by the manufacturer. In an extensible system, the structure of the system should be stable, but it should be supported to add new or old components without affecting the entire system. VIII, operation and maintenance In the final stage, apply to the user's hand, you must provide training, documentation, and education. Users will find problems and may make new improvements. You must handle these needs by correctly modifying management processes. You don't have to close a working system in order to configure a new component or replace an old component. System development procedures We must do a lot of system decisions, so we must organize a process of development. For a company, there are usually many application projects, some of which will even cross a few years, resulting in a variation of a system around many cycles. In your field, many of the same projects will have the same needs. You should easily reuse an extended and reusable system, which may be in the previous project cycle or other project. This will have a demand for universal architectures, and reusable software architecture provides a universal architecture for family-style software applications. If this is your first J2EE project, your system must be protected, test, analyze, and then repeat. Blueprint provides a lot of good design guidelines and best exercises, and an example of a pet store is also a good reference system. Effective ways to quickly propose a good and high-quality solution is to use and extend the BluePrint reference system, then insert into your own business components. With the reference system, I understand that the essence of the pet store system is Model-View-Controller and Command model. You can apply these models to systems that are web-centric and ejb-centricic. For each domain object, a view is with nested JSP performance. A Controller handles events related to business, while domain objects package business logic, transaction, and security. We use the front desk servlet as the central Controller to receive and explain all users' operations. It dispatches business events to the specified domain object Controllers, which call the domain object to change the continuous state. According to the result of this event, a Controller selects the next view of the next display. The following components are important for systems, we can modify and apply in most J2EE applications: MainServlet: The front desk is the interface between the web container and the architecture ModelUpDateListener: Yes to get the model update event. ModeEnotenotifier : Notifying the listener requestProcessor: Processing all requests, request, requestHandler: Plug-n-play request, requests, request, request, request, request, request, request, request, request, request, request, request, request, request, request, request, request, request, request, request, request, request, request, request, request, request, request, request, request, regulator mapping rule, request, request, processor: Mapping Rules, the central request processor approves request to process to the PLUG-N-Play request processing component.
