1. CourseOutline Example & JavaBeans Lec - 36

2. 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

3. Program Flow index.jsp controller.jsp web.jsp java.jsp If page = = web If page = = java

4. 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

5. JavaBeans

6. 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

7. 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

8. 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; }

9. 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

10. 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

11. Example Code Incorporating JavaBeans in CourseOutline Example