CourseOutline Example

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CourseOutline Example JavaBeans

• Lec - 36

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Start with Example Displaying Course Outlines

• User will select either course web design
  development or java.
• On submitting request, course outline would be
  displayed of the selected course from database

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Program Flow
web.jsp
If page web
index.jsp
controller .jsp
If page java
java.jsp
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Issues with Last Example

• Too much cluttered code in JSP
• Difficult to understand
• A single page is doing everything bad approach
• Displaying contents (Presentation logic)
• Connecting with database (DB connectivity logic)
• Results Processing (Business Logic)
• Solution
• Use JavaBeans

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JavaBeans
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What are JavaBeans?

• Java class that can be easily reused and composed
  together in an application
• Any java class that follows certain design
  conventions can be a JavaBeans component

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JavaBeans Design Conventions

• A bean class must have a zero argument
  constructor
• A bean class should not have any public instance
  variables (fields)
• Private values should be accessed through
  setters/getters
• For boolean data types, use boolean isXXX( )
  setXXX(boolean)
• A bean class must be serializable

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A Sample JavaBean

• public class MyBean implements Serializable
• private String name
• // zero argument constructor
• public MyBean( )
• name
• // standard setter
• public void setName(String n)
• name n

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A Sample JavaBean cont.

• // standard getter
• public String getName( )
• return name
• // any other method
• public void print( )
• System.out.println(Name is name)
• // end Bean class

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Incorporating Bean in Last Example

• Create a CourseOutlineBean
• Has following attributes
• sessionNo
• topic
• assignment
• Create a CourseDAO (bean)
• Encapsualte database connectivity logic
• web.jsp java.jsp will use these beans

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Example Code

• Incorporating JavaBeans in
• CourseOutline Example