JavaServer:

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JavaServer Web Solutions Through Java
Presenter Nick Meshes NickISPro_at_aol.com www.meshe
s.com
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• Open DOS Prompt
• Type javac and read output
• Change directory to bin
• Type startup

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• Quick History of Web Technologies
• Architecture of the Web
• Browser and Server Technology
• Two-tiered, Three-tiered, N-tiered Models
• Basics of Communication Socket
• Some Socket Examples
• What is a Servlet?
• The Servlet Engine
• Lifecycle of a Servlet

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• HelloWorld Servlet
• SendMail Servlet
• What are JavaServer Pages (JSP)?
• Elements of a JSP
• Some JSP Examples

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• Quick History of Web Technologies
• HyperText Markup Language (HTML)
• Flat text files representing text and images
  laid out on a screen
• (Common Gateway Interface) CGI
• Server-side processing
• Not scalable or flexible
• Microsofts Active Server Pages
• Provided clean conection to data sources
• Managed page, session, application

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• Quick History of Web Technologies
• Microsofts Active Server Pages
• Separated presentation from model
• Limited tasks could be performed in script
• Java Server Solutions
• Portable (NT, Unix, Mac, etc.)
• Flexible (receiving text, objects, bridging)
• Lightweight (load as needed, threading)
• Handle JNDI, JDBC, RMI, EJB, etc.

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Web Server
Request
Server Side Services
Response
Data Sources
Universal Resource Locator (URL) Address web
browser uses to find web services
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• Server Side
• File Server
• CGI
• Active Server Pages
• Java Servlets
• JavaServer Pages

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• Client Side
• HyperText Markup Language (HTML)
• Scripting
• Dynamic HTML
• JavaScript
• Data Handling
• Extensible Markup Language (XML)
• Applications
• ActiveX Controls
• Applets
• Plug-ins

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• Web Servers
• Apache (most common, free,
• http//www.apache.org
• Internet Information Server / PWS
• Netscape Enterprise
• Many others...

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• Web browsers
• Internet Explorer
• Netscape Navigator
• Many others...

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• Two-Tiered
• Server merely acts as file retrieval
• Too much load on PC
• Small changes means big rollouts
• Three-Tiered
• Client only receives data and formats it
• Server handles most processing
• Implementation details are hidden
• Main issue Stovepipes
• New service means new server

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• N-Tiered
• Presentation details same as 3-Tier
• All servers talk to each other
• Common interfaces between servers
• Implementation details are hidden between servers

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• Basis of all communication between computers
• How it works
• Opens a port on local system
• Connect with remote listening port
• Listener passes connection to new socket
• Transmit and receive data between sockets
• Close socket connection upon completion

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• URL Connection (Client Socket)
• Echo Server (Server Socket)
• Client Connection (Standard Socket)

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• Small specialized server implemented in Java
• What it does
• Receives HTTP requests
• Does some processing
• Data sources or other servers
• Returns an HTTP Response
• Runs under a JVM
• Handled within a Servlet Container (Engine)
• Each servlet is handled in its own thread
• Web server can talk to servlet
• Stand-alone / In-process / Out-of-process

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• Handles network connection
• Receives request, returns response
• HTTPRequest, HTTPResponse objects to Servlet

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• Instantiate the servlet
• Servlet.init()
• Servlet.service()
• Thread is recycled
• On Engine close, Servlet.destroy()
• Garbage Collection

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• getServletConfig() to get Context
• doGet(Request, Response)
• doPost(Request, Response)
• Lets do some examples!