J2EE This application model allows different developers to be developed at the same time. Here is the technical requirements of different levels of designers and developers. The following classifications are described. 1. Designers set the team 2, the team role of the logical layer 3, the business logic layer and other team characters 4, the composition of the team role team of the database access layer can be based on the number of people and the range of the system. For example, there is not necessarily all the characters to be assigned, and some people can act in a role.
****** Designer ****** In the development of components, one or several people must have a comprehensive understanding of the overall demand of this system, such as system control flow, and other interfaces, etc. Wait. Some companies call this role as a general engineer, no matter how calling, this role is very important, he assumes the work between different development groups to help them consider this "big picture".
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In the performance layer, the user interface is dynamically generated. The following developers are required: 1. Java servlet developers 2, JSP developers 3, HTML Designers 4, US workers 5. The client's JavaScript developers servlet developers build the logic of the performance layer, while others build the form of performance.
Java servlet developers
Servlet handling page and page browsing, session management, simple input verification. Servlet also connects the elements of business logic. Servlet developers must understand some relevant matters, HTTP requests, security, multi-language, and some page elements such as session, cookie, timeout, and more. In the application of J2EE, servlet must be written in Java, and servlet may call JSP, EJB, JDBC, and more. Therefore, servlet developers should work closely with other people in the application system.
JSP developer
JSP developers work closely with servlet developers to define the performance layer page of the system. Even in complex development projects, JSP and servlet developers may also be a person. However, if most Java in a system is in servlet instead of JSP, JSP people do not have to be familiar with Java.
HTML designer
HTML designers optimize the HTML page. For example, he may have to complete the following tasks:
1. Ensure that all pages in different browsers can be displayed normally, ensuring that low-speed modem access is not affected 3, further optimization of the page of JSP designers
Worker
US workers create pictures, etc.. These pictures can be small volume and download it quickly. The American worker works closely with HTML pages.
The client's JavaScript developers use the client's JavaScript for many reasons. For example, you can handle simple input verification, you don't have to submit it to the server, you can also make the user interface more vivid. This role and servlet, JSP personnel work closely together.
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The business logic layer contains business rules and business entities. Need:
1, session bean developer 2, Entity Bean developers
Session bean developers
Session Beans contains logic of business processing and business rules. For example, a session bean may be designed to calculate the tax rate of a check. If a system faces complex logic that changes frequently, it uses a large number of session beans. As a result, session beans require constant updates. The developers of session beans are generally an expert in a field, understand complex, specialized field logic, and the rules of data verification. This person works closely with Servlet and Entity Bean developers. Session beans may need to call JDBC interfaces, and other EJBs. There is a better SESSION bean system running. Because if the calculation rate is a stateful Session bean, the system must access a server that saves the status information of the bean. If that server happens to happen, the entire process will be blocked. Entity Bean Developer
Entity Bean represents a permanent object, such as a record in a database. The Entity Bean developer's task is to design an organizational map for all object-oriented services. Establishing an object-oriented trial means that the table (relational) in the database is to be mapped into Entity Bean. For example, developers need to convert client tables, invoices, and order tables into corresponding customers, invoices, and order objects. An Entity Bean developer works closely with Session Bean, servlet developers to ensure that the application provides quick, flexible, scalable to business data access. Entity Beans may call a large number of JDBC interfaces. The call between the Entity Bean will be very small.
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In the database access layer, developers need to establish a related document, data dictionary, etc. related documentation. All databases, access, and so on, have access to the database. This role acts as a DBA role in most projects.
After the team is built, you can start designing the user interface.
************ Design User Interface ************
It is recommended to design an application system afterwards. That is to say, first design the user interface, then design EJB, which is the highest efficiency. Anbo has done a lot of interface design, and the future work can be fully referred to existing design. Take some common recommendations: 1. What is the page process? 2, what is the command button on each page? 3, is it suitable for Frame? 4. Is there a company standard logo, an advertising banner? 5, where is the login process? 6, multi-language problem? These and design servlets, JSPs are related.
