即时焦点：java自学用书：导论Java程序设计

【实例简介】

该书适合刚入手java的童鞋，该书由浅入深，是一个不错的自学用书。

(资料图片)

导论

Java程序设计

导论

1.1 Hello, World!

程序清单1: Hello world.iava

1/

2*@(#)HelloWorld. java 0.30 08/28/10

4* Show message” Hello, World!” in Console

6 @author xiaohua xu

*@ version②.30

8 *k @ since 0.20

@see System. in

11

12

13 public class HelloWorld t

public static void main(String args)t

6

System. out. println( "Hello, World!

18}

程序清单2: Hello WorldDialog java

1

2 *@(#)HelloWorldDialog java 0.20 08/28/10

4* Show message Hello, World!" in JOptionPane

6 @author xiaohua xu

@version 0.30

8 @since 0.20

9 @see javax. swing JOptionPane

OT

12 import javax. swing JOptionPane

13

14 public class Hel loWor ldDialog i

5678

String message =>Hello, World!

public static void main (Stringl arg

JOptionPane showMessageDialog(nuLl, message);

1

20

程序清单3: Hello WorldApp.java

/

半米

2*@#)He L ldApp. java 0.30 08/28/10

4* Show message Hello, World! in Console

DONT DⅠSTRⅠ BUTE IT!

April 15,2012

2基础知识

Java程序设计

6 *k @author Xiaohua xu

7 @version 0.30

8 *k @since 0.20

@see System. in

10

12 public class he l lowor ldapp i

13

public void maino i

System, out. print("Hello, World! )

System, out. println(;

11111

56789

public static void main (String] args)t

Hel ldApp app= new He l loWor ldApp;

20

app. main(

21

2

12 Unicode演示

匚程序清单4 UnicodeDemo

1/*米

2* @(#Uni codeDemo, java 0. 20 08/28/10

4* Show Uni code u2122 as Java

TM

6 @author Xiaohua Xu

@version 0.20

8 @since 0.10

9 @see JoptionPane

1O冰

12 pubLic class Uni code Demo I

3

public static final char TRADE_MARK \u2122

15 public static void show (String str)i

javax. swing.JOptionPane showMessageDialog(nuLl, str);

1112

public static void main (String args)t

String message=”Java”+ TRADE MARK;

System, out. println(message);

show (message)

System. exit(o);

26

2基础知识

21加法

DONT DⅠSTRⅠ BUTE IT!

April 15,2012

2基础知识

Java程序设计

程序清单 Addition.java

1/**

2 * @(*)Addition. java

4 *@author Xiaohua Xu

5*@ version0.92009/03/05

8 import javax. swing JOptionPane

10 public class Addition i

public static void main( Stringl] args)t

111

String firstNumber;

String secondNumber

16

int number 1

int number 2

18

int sum,

19

firstNumber JOptionPane showInputDialog("First Num)

secondNumber OPtion Pane. showInputDialog ("Second Num

number1 Integer parseInt(firstNumber )

2345

number 2 Integer parseInt(secondNumber);

sum number 1+ number 2

J0ption Pane showMessageDialogo

6789o

The Sum is:”+sum

Results”

JOptionPane PLAIN_MESSAGE

32

System. exit( 0

22浮点数注意

程序清单6: DoubleDemo. java

/*

2 *@(#)DoubL eDemo java

4* @author Xiaohua Xu

5*@ verslon1.02009/03/05

8 public class Doub leDemo t

public static void main(String args)t

double x=0.0:

//初始量

12

double delta =0.1

增长量

int n=10

//迭代次数

14

5

System. out. println(x)

//输出到屏幕

DONT DⅠSTRⅠ BUTE IT!

April 15,2012

2基础知识

Java程序设计

for(int讠=0;i

1

678

x t= delta

/每次递增 delta

System. out. println(x);

//屏幕输出

19

0

21

23数值最值

程序清单z: MaxMin ValueOfVariableDemo java

1/*米

2 *@(#)MaxMinValueOfVariableDemo java

3*输出冬和变量的最大值和最小值

@author Xiaohua Xu

6*@ verslon1.0010/03/15

9 public class MaxMinValueOfVariableDemo t

10

public static void main(Stringl args) t

11

System. out. printInG The largest byte value is

+ Byte. MAX_ VALUE+”,”);

13

System. out. printLn( The smallest byte value is

+ Byte. MIN_VALUE+”.”);

15

System, out. println( The largest short value is

1

+ Short. maX_ VALUE+”.”);

8

System, out println("The smallest short value is

+ Short. MIN VALUE+”.”);

20

System, out. println( The largest integer value is

2

+ Integer. MAX VALUE+”.”);

System, out. println(" The smallest integer value is

+工 nteger MIN_ VALUE+”.”);

System. out. println( The largest long value is

Long MAX VALUE

System. out. println(" The largest long value is

2

Long. MIN_VALUE+”.);

30

31

ystem, out. printLn The largest float value is

+ FLoat. MAX VALUE+”.”);

33

System, out. printLn( The smallest float value is

34

+ Float. MIN value+”.”);

35

36

System, out. println(The largest double value is

+ Double. mAX_VALU+”.”);

System, out. println( The smallest double value is

+ Double. MIN VALUE+”.”)

41

42

循环

DONT DⅠSTRⅠ BUTE IT!

April 15,2012

2基础知识

Java程序设计

程序清单8: WhileDo. java

1/**

2 *@(#)WhileDo. java

4* Since b"" is already false when it reaches the

5* test, the loop never executes

@author Xiaohua xu

8*@ verslon.92009/03/05

11 public class Whiledo i

12

public static void main(String args)t

boolean b= false:

1111

4567

while( b)i

System. out. println( Execute WhileDo while b is true);

tt toc

1

程序清单g: WhileDoTest. java

/

@(#WhiLe DoTest java

4*@author Xiaohua Xu

5*@ verslon0.92009/03/05

8 import javax. Swing JOptionPane

10 public class Whiledotest t

11

11

2

public static void main(String[] args)t

int b= 2

int s=

1

while( b>s)t

18

JOptionPane. showMessageDialogo

1

null

0

Big is still bigger”

21

Results

2

JOption Pane. INFORMATION_ MESSAGE

String big =JOptionPane. showInputDialog("Big Number>)

26

String small= JOptionPane show InputDialog( SmaLl Number

b= Integer parseInt( big )

Integer parseInt( smaLl)

31

ystem. exit(0);

DONT DⅠSTRⅠ BUTE IT!

April 15,2012

2基础知识

Java程序设计

32

33

程序清单10: Do While. java

2 * @()DoWhileTest java

4*@author Xiaohua Xu

5*@ version0.92009/03/05

7 import javax. swing JOptionPane;

9 public class DoWhileTest t

public static void main ([ args)t

int b= 2;// preload variables

int s= 1;// preload variables

1111111

4

do t

56789

JOptionPane. showMessageDialogo

null

Big is still Bigger”

Results”,

JOption Pane INFORMATION_MESSAGE

222

012345

String big JOptionPane showInputDialog("Big Number")

String smaLl= JOptionPane. showInputDialog("SmaLl Number

26

b= Integer parseInt(big)

2

s=Integer parseInt(smaLL)

789o

f while(b> s;

System, exit( 0)

31

32

25选择

程序清单11: Selection Test java

米*/I

2* @()SelectionTest java

4* @author Xiaohua Xu

5*@ version9.92009/03/05

6*/

8 import javax. swing JOptionPane;

10 public class SelectionTest t

public static void main(String[ args) t

DONT DⅠSTRⅠ BUTE IT!

April 15,2012

2基础知识

Java程序设计

14

String big JOptionPane showInputDialog("Big Number>)

15

String small= J0ptionPane showInputDialog( SmaLL Number)

int b= Integer parseInt(big);

比t

Integer parseInt(smaLl);

1

1

String out =(b>s? Big was Larger: Small was larger

20

JOptionPane showMessageDialog(nuLl, out

Results", OPtion Pane. INFORMATION_MESSAGE

System. exit(0);

26

2.6增量

程序清单12: PrePostIncrement. java

/*米

2 *@(#PrePostIncrement java

4* @author Xiaohua Xu

5*@ verslon0.92009/03/05

8 public class PrepostIncrement

public static void main (String args)

11

int x= a

12

System.out. println(” Baseline,x=”+x);

System, out. println( >Pre-increment =++x=>+++X )

1

System, out. printLn( "After increment, x="+X);

X=0;

System,out. println(” 2nd baseline,x=”+×);

System. out. println( "Post-increment = X++=3+X++)

1

System, out. println( After increment,x

X

//System. exit( 0);

27温度转换

程序清单13: FahrenheitToCelsius.java

2 *@(#)FahrenheitToCelsius java

4* celsius =9(fahrenheit- 32)

@author xiaohua Xu

7*@ version0.92009/03/05

DONT DⅠSTRⅠ BUTE IT!

April 15,2012

3简单程序

Java程序设计

10 public class FahrenheitTocelsius i

public static void main(String args)t

double fahrenheit 100;

111111

double celsius =(5.0/9.0*(fahrenheit -32)

4567890

System. out. println(” Fahrenheit”+ fahrenheit+”is

+ celsius+” in Celsius.”);

3简单程序

31数学工具

程序清单14: AbsDemo.java

1/*米

2 *@(#) AbsDemojava

木

4 @author Xiaohua Xu

5*@ version1.002009/03/05

9 public class absDemo t

12

public static void main(Stringl args)t

double x =-0.0.

1

System.out, println(”abs(”++”)=”+Math.abs(x));

6

20

System. out. println(”abs(”+×+”)=”+Math.abs(x);

Double. POSITIVE INFINITY

ystem.out. println(”abs(”+x+”)=”+Math.abs(x);

x= Double NeGATive Infinity

System. out. println(”abs(”+Ⅹ+”)

Math. abs(x))

x= Double nan

System. out. println(”abs(”+x+”)=”+Math.abs(x));

10.5

30

double y

20.1

31

System.out. println(”max(”+x+

y+”)

Math. max

32

System.out. println(”mix(”+X+”,”+y+”)=”+Math.min

33

ystem.out. println(”max”+x+

十

nax(x, y

DONT DⅠSTRⅠ BUTE IT!

10

April 15, 2012

【实例截图】

【核心代码】