Chapter 7c: Servlets, JSP, HTTP Monitoring

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Chapter 7cServlets, JSP, HTTP Monitoring
Reference Eclipse WTP
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Objectives

• Servlets
• Details in separate slides
• What are JavaBeans?
• JavaBean Usage within JSPs
• Access JavaBeans with JSP Standard Actions
• Access JavaBeans from scriptlets
• Monitoring HTTP Sessions

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Servlets

• Acts as the input controller
• Generates dynamic output
• Code Samples
• Chapter 3, iteration 2 Web1
• HelloServlet
• Chapter 7, iteration 7 IceHockeyWeb
• LoginServlet (validates user/password)
• EditScoreServlet (save scores to object)
• ScheduleServlet (with XML transformation)

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What Are JavaBeans?

• Javas software component model specification
• Written in Java platform neutral
• JavaBean Characteristics
• Must have a default (zero-argument) constructor
• Used when restoring JavaBean from a file
• Must be serializable
• Implements java.io.Serializable
• Can save JavaBean to a file
• Note Many non-visual JavaBeans do not conform to
  this requirement.
• Private instance variables
• Public features (methods, properties, events)

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JavaBean Property Types

• Simple
• Use standard getter/setter signatures
• E.g., public String getName()
• Boolean
• Use isltPropertyNamegt for getter method
• E.g., public boolean isValid()
• Indexed
• Represents an array of values
• Use java.util.ArrayList for dynamic arrays
• E.g., public ArrayList getValues()

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Coding a JavaBean

• Reference Page 281
• Eclipse WTP
• Use wizard to create getter/setter methods
• E.g., User.java
• Add instance variable(s)
• private boolean loggedIn false
• private String userId ""
• Add getter/setter methods
• public boolean isLoggedIn() return loggedIn
• public void setLoggedIn(boolean loggedIn)
  this.loggedIn loggedIn

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JavaBean as Data Transfer Objects

• JavaBeans carry data between pages
• Between business logic and presentation layer.
• E.g., logout.jsp
• Creates User JavaBean instance named user
• ltjspuseBean class"com.leagueplanet.User"
  id"user" scope"session" /gt
• Access user property values
• Using JSP Action ltjspgetProperty name"user"
  property"userId" /gt
• Using Scriptlet lt user.getUserId() gt

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JavaBean, JSP Servlets

• Chapter 7, iteration 7 IceHockeyWeb
• Run login.jsp

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Eclipse WTP Monitoring HTTP Sessions

• Monitor LoginServlets HTTP traffic
• Pages 289 - 293
• Tomcat 6.x Server
• Monitoring Properties

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Eclipse WTP HTTP Port to Monitor

• Add and start monitoring HTTP Port
• Note WTP may change port to listen (from 8081 to
  14163)

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Run JSP/Servlet Using Monitored HTTP Port

• URL http//localhost14163/IceHockeyWeb/login.jsp

• To display Window Show View Debug TCP/IP
  Monitor

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Next Steps

• Chapter 7
• Iterations 6 8
• Assignment 2