There are 2 types of enterprise application
- Web application
- Distributed applications
1) What are the differences between web applications and distributed applications?
A: Web applications are the server side applications, which will be designed without distributing application logic over more than one JVM
- Distributed applications are the java applications, which will be designed by distributing application logic over more than one JVM
2) Web applications will be designed by using web technologies like CGI, Servlet , JSPS
Distributed applications will be designed by using the technologies like socket programming, RMI,EJBS, CORBA, Web services.
3) In case of web application, no separate java program for client in case of distributed application, there is a separate java program fore client and fore server.
4) web application is a collection of web components like servlet, JSPS,— which will be executed by using only web containers.
Distributed application is a collection of distributed components like EJBS, Which will be executed by using EJB Container.
5) Web applications will be executed by both web servers and application servers.
Distributed applications will be executed by only application servers.
6) Web applications will provide services for only web client is browser
Distributed application will provide services for only type of client.
In case of distributed applications, client may be any thing like a java program with main() method. An applet, a servlet, a JSP page, frame work specific components like action classes in struts and managed beans in JSF,
7) The main purpose at web application initially to general static response from server and distributed applications is to generate dynamic response.
- At present the intention of web application to generate dynamic response from server machine and distributed application is to establish connection abut n local machine and remote machine in order to get remote services from remote machine
8) It we want to use more web application and distributed application with in a single enterprise application then we will use web application to implement presentation and part we will use distributed application to implement business logic.
Web application development models
To design web application in a standard pattern, we have to use the following models.
1.Model- I Arch
2.Model- I Arch
1.Model- I Arch
In this arch, a JSP page is a configure as controller, it will take responsibility to pick up requests clients and to control the entire web application
- In model- I Arch, a java bean component will be used as model part to execute application business logic
- Model-I arch, is also called “JSP Front”, because a single JSP page is acting as front controller to requests and to control web application.
- Model –I Arch, is also called as page centric arch, because a single JSP page is controlling the entire web application
- In model-I Arch a single JSP page is acting as controller, to control the entire web application the existed JSP features will not be sufficient it required to code in JSP pages, providing java code inside JSP page is not suggestible
- In model-I arch, there is no separation bet n presentation logic and controller logic, it may provide tightly coupled design for the web application.
- To over come all the problems we have to go for model II Architecture.
Model –IT Arch
- In model s arch. We will use a servlet as controller and a set of JSP pages as view parted
- Model ii arch. Is also called as “Servlet front” because a single servlet is taking responsibilities to pick up all the request from client.
- Model IT Arch is also called as “Servlet control ”arch because a single servlet is controlling the complete web application.
- Model –II arch is purely an implementation of MVC design pattern
Struts an JSF like frame works are designed on the basis of model II web application architecture lie on the basis of MVC design pattern