Design And Implementation Of Web Application Server Based On J2EE

Application server is a chief platform of Web-based application. In order to support seamless access to the DM DBMS at the multiple architecture for the web clients, we design and implement a web application server named DM WAS based on J2EE. It enables the web clients to deploy web applications conveniently and to access the storage service provided by DM DBMS seamlessly.After the research of the general requirements for the web application server and the component-based software development pattern, we advance the ensemble modular architecture of DM WAS conforming to J2EE specification and HTTP protocol. In DM WAS, the functions are provided by the components and the communication of these components implement the control flow of the server. This architecture adapts to the necessary of expanding function.DM WAS manages every component in the server using the life cycle technology. We expand the default ClassLoader pattern of Java into a divergent tree structure, which protect the core server library and fulfill the necessary for the hot deploying of web applications. Considering that there are many intercurrent visits on the server in the web environment, we use the multiple threads based on the thread pool technology to smooth out the latent resource absence problem. We ameliorate the server performance with preprocessing the JSP and buffering the servlets. In the implement of server session management, we endow every client participating in the session with a session object that has a unique session ID. The session is maintained using cookies or rewriting URLs and can be saved in the memory or in the persistent medium such as the DBMS. In order to enhance the efficiency of connecting the database, we accomplish a connection buffered pool based on the JDBC DataSource API. The pool can buffer the physical and logical database connections. We also think about the server security. The authentication and authorization are both provided. The HTTP Basic authentication and Form-based authentication are two optional authentication methods. The role based access control is used in our authorization. In the end, we discuss that how to integrate DM EJB server into DM WAS using JNDI.