Advanced Java Class

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Advanced Java Class

• Web Applications Part 0
• (Introduction)

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Intro to Web Apps

• web apps vs. web sites
• server-side processing
• web apps vs. network programming
• takes advantage of abstractions that cover
  communications layer, security, etc.
• requires web server application server web
  client software
• Webs app API is part of J2EE

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Web technology
See figure 13-1 on page 815 for a cleaner
version.
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HTTP and HTTPS protocols

• "S" is for secure
• An exchange request response
• Each exchange is independent ("stateless")
• HTTP request methods
• GET put form values in URL (visible, limited
  length)
• POST put form values in embedded header
  (invisible, any length)

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URLs, Identifiers, and Names

• protocol//domainNameport/resourceName
• resourceName folder path file
• protocols HTTP, HTTPS, FTP, etc.
• domain Name host Name, IP address, etc.
• port default for HTTP80, HTTPS443

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HTML XHTML Documents

• XML is strict (grammatically)
• HTML has all the popular mark-ups
• XHTML is both (therefore preferred)

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Servlets

• Inside a web-app, on the server-side
• Generally "alive" while web app is alive
• Respond to HTTP requests

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ViewControllerModel Layers

• View Web pages shown on client side
• Controller Servlet (server-side class)
• Model Other server side classes
• access DB, server-side files
• security-sensitive tasks
• processor-heavy operations
• network communications

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Digital Flashcards Example Activity

• Divide each task into subtasks.
• Which subtasks should be done at each level of
  the application (VMC), and what file type or Java
  object should be responsible for the subtask?
• Tasks
• Logging in a user
• Allowing a user to enter a new word
• Quizzing a user on a list of words and recording
  the results.