Java Programming - Chapter 6 (in Thai)

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Computer Programming using JavaFile Operations - 06

CHAPTER

6

(File Operations)

1. (Characteristic of File)

1. 1)

(File / Text File) * . txt , *. dat

2)

()3) () 4)

(1 = 1 Byte)

2.

[1] [2] 1) (Reading File)

2)

(Writing File)

2. (Reading and Writing Files)

1.

Scanner 2 -1)

Scanner java.io Scanner java.io import java.util.Scanner;import java.io.*;

"dat a. t xt " Notepad

* . txt


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Computer Programming using Java 06 - File Operations

1

2

345

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4567

12345

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78

2) ( mai n) throws IOException

3)

4)

1-3 hasNext()(Boolean)

import java.util.Scanner;import java.io.*;

publ i c cl ass Test {. . .

}

i mpor t 2

i mpor t j ava. ut i l . Scanner ;i mpor t j ava. i o. * ;publ i c cl ass Test {

publ i c stati c voi d mai n( St r i ng[ ] ar gs) throws IOException {. . .}

}

Scanner = new Scanner ( new Fi l e( "") ) ;


publ i c st at i c voi d mai n( St r i ng[ ] ar gs) t hr ows I OExcept i on {Scanner in = new Scanner(new File("data.txt"));

. . .

}}

Fi l e = new Fi l e( "")Scanner = new Scanner ( ) ;

Syst em. i n i n

dat a. t xt

whi l e( . hasNext()) {. . .}

(Next )

t hrowss

()


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5) -

(1)i nt next I nt ( )

i nt num = i n. next I nt ( ) ; (2)doubl enext Doubl e( )

doubl e d = i n. next Doubl e( ) ; (3)Str i ngnext Li ne( )

St r i ng s1 = i n. nextLi ne( ) ; (4)St r i ng(\ t \ n)

next( )

St r i ng s2 = i n. next( ) ;

6)

close()

7)

i nt = .nextInt();

doubl e = .nextDouble();

St r i ng = .nextLine();

St r i ng = .next();

next I nt ( )

.close();


publ i c cl ass Test {publ i c stati c voi d mai n( St r i ng[ ] ar gs) throws IOException {Scanner in = new Scanner(new File("d:/cu/student.dat"));

i nt i = 1;while(in.hasNext()) {

St r i ng s = i n. next Li ne( ) ;Syst em. out . pr i nt l n( i + " : " + s) ;i ++;

}in.close();

}}

st udent . dat

i n. cl ose( ) ;

Full Path


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1 [] (12 )

2 [] data.txt (Number of Lines) (10 )

test.txt1234

5

Scanner i n = new Scanner ( new Fi l e( " t est . t xt " ) ) ;whi l e (i n. hasNext ( ) ) {System.out.println( );

}

i n. cl ose( ) ;

in.nextInt() in.nextDouble() in.nextLine() in.next()

while while while while

1 2 345 6

7. 0 8 9D 0


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3 [] data.txt (Number of Words) (10 )

4 [

]

data.txt

(Number of Characters) (10 )


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5 [] student.txt 2110191 Innovative Thinking

(10 )

21import java.util.Scanner;

import java.io.*;public class CountEngStudent {

public static void main(String[] args) throws IOException {

} //End of main

} //End of class

6 [] score.txt(100 )

60 S U (10 )


public class StudentGrade {

public static void main(String[] args) throws IOException {

score.txt

1. 5330000221 U2. 5330000320 S3. 5330000421 S4. 5330000521 U5. 5330000622 S. . .

5330000221 45. 23 215330000320 72. 45 205330000421 91. 11 215330000521 38. 20 215330000622 60. 00 22. . .

student.txt

Engi neer i ng St udent s: 2

1. Wongyos Kear dsr i 52718228212. Wannapor n Yi m- ngam 53300234223. Ong- ar d Rut samee 5230586021. . .


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} //End of main} //End of class

7 [ ] student.dat

(15 )1) 5330000121 1st2)

1 Preecha P. wongyos W.

3)

2.00 Pass 1.002.00Critical 1.00Retired4)

import java.util.Scanner;

import java.io.*;public class StudentInfoFromFile {public static void main(String[] args) throws IOException {

1. 4830000121 6t h P. Ler dsi r i kul 1. 99 Cr i t i cal2. 5230000221 2nd S. Chokkhoukhang 2. 02 Pass3. 5330000321 1st R. Suksawat dee 0. 56 Ret i r ed. . .

student.dat

4830000121preechaLerds i r i kul1. 995230000221Suwar apornChokkhoukhang2. 025330000321

Ruksaj aiSuksawat dee0. 56. . .


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8 [ ] love song.txt 2 () love you my lovely love 1 () love you my lovely love 2 (15 )

Count Wor ds #1: 3Count Wor ds #2: 7

I Love you al l over LOvE j ava.I l OVe some l ovel y f r i end.Lovel oVe j ava! ! .

song.txt


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9 [] data1.dat data2.dat 2110101 2552 2553 F

F (15 )

import java.util.Scanner;

import java.io.*;public class FComparison {public static void main(String[] args) throws IOException {

No. Student I D Gr ade========================1. 5230000121 C+2. 5230000221 A3. 5230000321 B+4. 5230000421 F5. 5230000521 B. . .

data1.dat

No. Student I D Gr ade========================1. 5330000121 F2. 5330000221 F3. 5330000321 F4. 5330000421 D+5. 5330000521 A. . .

data2.dat


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2.

PrintStream 1) PrintStream PrintStream

java.io import java.io.*;

2)

throws IOException


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12345

678

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1011

3)

4)

1)

out . pr i nt ( "St ar t New Fi l e") ; 2)

out . pr i nt l n( "St ar t New Fi l e") ;

5) close()

6)

10 [] -

sentence.txt Stop (10 )

.println( ) ;

.print( ) ;

Pr i nt St r eam = new Pr i ntSt r eam( new Fi l e( "") ) ;


publ i c st at i c voi d mai n( St r i ng[ ] ar gs) t hr ows I OExcept i on {PrintStream out = new PrintStream(new File("data.txt"));

. . .}

} out dat a. t xt

i mpor t j ava. ut i l . Scanner ;import java.io.*;

publ i c cl ass Test {publ i c stati c voi d mai n( St r i ng[ ] ar gs) throws IOException {PrintStream out = new PrintStream(new File("data.dat"));

f or ( i nt i = 1; i


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11 [] text.txt We love java avaj evol eW revtext.txt(15 )

text.txt

We l ove j ava

J ava i s my f i r st programmi ng andJ ava i s my l ast programmi ng. . .

revtext.txt

avaj evol eW

dna gni mmar gorp t sr i f ym si avaJgni mmar gorp t sal ym si avaJ. . .

Java Programming - Chapter 6 (in Thai)

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