This document discusses object-oriented programming (OOP) concepts like classes, objects, properties, and methods. It provides examples of creating classes in Java, instantiating objects from classes, and using constructors. It also demonstrates overloading constructors and the use of the 'this' keyword. Finally, it shows examples of using the File System Object in classic ASP to read from and write to text files.

1. java

3. OOP
•
•
Problem Space)

4. class)
object)
• scripting language
Perl PHP
• class
members) properties)
member functions)
class { ... }
class constructor
new
class constructor

6. •
static
instance
instance

7. • MyClass
n x n
static Method 1 getX()
instance
•
• MyClass a = new MyClass();
• MyClass b = new MyClass();

8. • instance
x instance
x
instance) n
static
instance n
reference MyClass
n
n Class
Variable" n
MyClass.n instance

9. • Method
reference Method
Method
MyClass) instance
Method
instance reference
Method
static

10. • static Method
• static Method
Method
instance
• printCircle
TestPass1 instance
printCircle static

12. constructor)

13. constructor)
•
constructor)
new

14. • //DriveAcar05.java
class Vehicle {
int numberOfWheels ;
boolean hasEngine ;
//constructor
Vehicle() { // (1)
numberOfWheels = 6 ;
hasEngine = true ;
}
void run() {
System.out.println("I am running") ;
}
}
public class DriveAcar05 {
public static void main(String[] args) {
Vehicle myCar = new Vehicle() ;
System.out.println("mycar has "+myCar.numberOfWheels+"Wheels.") ; // (2)
System.out.println("That mycar has an engin is "+myCar.hasEngine+".") ; // (3)
}
}

15. •
void
•
DriveAcar05.java
main()
Vehicle Vehicle myCar = new
Vehicle(); Vehicle()
numberOfWheels = 6 hasEngine =

16. •

17. • //DriveAcar06.java
class Vehicle {
int numberOfWheels ;
boolean hasEngine ;
//constructor
Vehicle() {
numberOfWheels = 6 ;
hasEngine = true ;
System.out.println("A car has been built") ; // (1) notice this line
}
void run() {
System.out.println("I am running") ;
}
}
public class DriveAcar06 {
public static void main(String[] args) {
Vehicle myCar = new Vehicle() ;
System.out.println("mycar has "+myCar.numberOfWheels+"Wheels.") ; // (2)
System.out.println("That mycar has an engin is "+myCar.hasEngine+".") ; // (3)
}
}

18. Overloading Constructor)
•

19. • //OverloadConstructor.java
class Vehicle {
int numberOfWheels ;
boolean hasEngine ;
//constructor and Overload Constructor
Vehicle() {
numberOfWheels = 6 ;
hasEngine = true ;
System.out.println("A car has been built") ; //notice this line
}
Vehicle(int number, boolean engine) { // (1)
numberOfWheels = number ;
hasEngine = engine ;
System.out.println("A car has been built") ; //notice this line
}
void run() {
System.out.println("I am running") ;
}
}
public class OverloadConstructor {
public static void main(String[] args) {
Vehicle myCar = new Vehicle(4,true) ; // (2)
System.out.println("mycar has "+myCar.numberOfWheels+"Wheels.") ;
System.out.println("That mycar has an engin is "+myCar.hasEngine+".") ;
}
}

20. • //TestThis.java this()
class A {
int a ;
A() {
a=0;
System.out.println("Default constructor") ;
}
A(int i) {
this() ;
a=i;
System.out.println("constructor 1 ") ;
}
A(int i, int j) {
this(i+j) ;
System.out.println("constructor 2 ") ;

21. • }
}
public class DriveAcar06 {
public static void main(String[] args) {
System.out.println("Instantiate x");
A x = new A() ;
System.out.println("Variable a is "+ x.a) ;
System.out.println("Instantiate y ");
A y = new A(5) ;
System.out.println("Variable a is "+ y.a) ;
System.out.println("Instantiate z ");
A z = new A(5,6) ;
System.out.println("Variable a is "+ z.a) ;
}
}
this()

23. • static File System File System
File Access
• File Access Component
• Set Fso= CreateObject("Scripting.FileSystemObject")
• Fso
File Access Component Fso
• Open Text File Method
•
• Object.openTextFile(filename[,iomode][,create][,Format]
•
• Object

24. • Filename
• ( Required)
• iomode
• ( Optional)
• ForReading(1)
• ForWriting(2)
• ForAppending(8)
• Create
• ( optional)
• True
• False
Error
False

25. • Format
• ( optional) Tristate
UseDefault(-2) ASCII
ASCII
• Tristate True(-1) Unicode
• Tristate False(0) ASCII
• ASCII
•
• Set fso= CreateObject("Scripting.FileSystemObject")
• Set Myfile=fso.openTextfile("c:testfile.txt",1, True)
• fso
File Access fso
OpenTextFile testfile.txt
• OpenTextFile
MyFile Text
Stream Object
• TextStream Object ( Text)
TextStream

26. • Close
• TextStream Object
• Read
•
• ReadAll
•
• ReadLine
•
• Skip
•
• SkipLine
•

27. • Write
•
• WriteLine
•
• WriteBlankLines
•

28. • Sample1.asp
• <% if request.form("message") = "" then %>
• <html>
• <body>
• <form action="sample1.asp" method="post">
• <font size=+1>
text</font><br>
• Name:
• <input type=text name=message size=30>
• <input type=submit value=
• form>

29. • <%
• else
• Set FileObject = Server.CreateObject("Scripting.FileSystemObject")
• MsgFile = Server.MapPath ("Text.txt")
• Set OutStream= FileObject.CreateTextFile (MsgFile, True)
• OutStream.WriteLine Request.Form("message")
• Set OutStream = Nothing
• Set MessageStr =Nothing
• %>
• a href="sample2.asp">sample2.asp</a>
• body>
• </html>
• <% end if %>
•
• Out Put

30. • Sample1.asp
•
• <html>
• <body>
• br>
• <%
• Set FileObject = Server.CreateObject("Scripting.FileSystemObject")
• MsgFile = Server.MapPath ("Text.txt")
• On Error Resume Next
• Set InStream= FileObject.OpenTextFile (MSGFile, 1, False, False)
• Response.Write Instream.ReadALL & "<BR>"
• Set Instream=Nothing
• %>
• </body>
• </html>
•
•
• Out Put
•