The second part of the Web application model and its Java implementation

Part II: Understanding two important ASP (Application Service Provider) models

Based on the introduction to the architecture in the previous section, this section provides a further overview of the architecture of Web applications and a detailed introduction to the two major Web application architectures.

1, from "Web content" to "Web application"

The advent of ASP (Application Service Provider), or the advent of Web applications, is the result of the growing technology and applications of the Internet. The early internet was used as a tool for providing static content to users, as shown in Figure 7.

Figure 7, the architecture of Web content

Web-based content is not the same as normal content presentation, it requires two of special applications, Web browsers, and Web servers. One important function of Web browsers is to contact the server, send content requests, and finally handle the server's response, while the Web server's function is to listen and respond to requests from web browsers. In the content-based Internet, most files that are requested and downloaded are HTML.

Static Web content does not meet user interactivity, so client-side scripting (VB script, Java script), DOM-based Dynamic HTML technology, client controls (ActiveX, applets) are present. These technologies improve the interactivity of Web content to some extent, but most of these technologies are related to Web browser platforms and do not guarantee that the content provided by the site is accessible to all browsers. These technologies are still categorized as Web content.

To design a web that is accessible to all browsers, you need to move the script from the Web browser side to the server side. Combining the form with the client's program technology (CGI, Servlet) and scripting Technology (Asp[active Server Page, JSP) will provide users with very rich content, a form of web content called Web applications. Figure 8 shows the infrastructure of the Web application.

As you can see from Figure 7 and Figure 8, we can't look at HTML, ASP, and JSP technologies in isolation, and we need to think of them as a whole with the environments in which they run. From this perspective, both Web content and Web applications are a layered application architecture.

Figure 8, architecture for Web applications

2, Microsoft's Web application development model

Microsoft's Web application architecture is a concrete implementation of the architecture shown in Figure 8, known as the DNA (distributed N-tier architecture) structure. Figure 9 shows the structure of Microsoft DNA.

Figure 9, Microsoft DNA architecture