Java

OOP
•

•

Problem Space)

class)
object)
• scripting language

Perl PHP

• class
members) properties)
member functions)
class { ... }

class constructor
new
class constructor

•

static
instance
instance

• MyClass
n x n
static Method 1 getX()
instance
•

• MyClass a = new MyClass();
• MyClass b = new MyClass();

• instance
x instance
x

instance) n
static

instance n
reference MyClass
n
n Class
Variable" n

MyClass.n instance

• Method

reference Method

Method

MyClass) instance
Method
instance reference
Method
static

• static Method
• static Method
Method
instance

• printCircle
TestPass1 instance
printCircle static

constructor)
•
constructor)

new

• //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)
}
}

•

void

•

DriveAcar05.java
main()
Vehicle Vehicle myCar = new
Vehicle(); Vehicle()

numberOfWheels = 6 hasEngine =

• //DriveAcar06.java
class Vehicle {
boolean hasEngine ;
//constructor
Vehicle() {
hasEngine = true ;
System.out.println("A car has been built") ; // (1) notice this line
}
void run() {
}
}
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)
}
}

• //OverloadConstructor.java
class Vehicle {
boolean hasEngine ;
//constructor and Overload Constructor
Vehicle() {
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() {
}
}
public class OverloadConstructor {
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+".") ;
}
}

• //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 ") ;

• }
}
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()

• 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

• Filename
• ( Required)
• iomode
• ( Optional)

• ForReading(1)
• ForWriting(2)
• ForAppending(8)

• Create
• ( optional)

• True

• False
Error
False

• 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

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

• Write
•
• WriteLine
•
• WriteBlankLines
•

• 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>

• <%
• 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

• 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
•

Java

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