Reading from a text file and storing it in another file

[Guest_imported]

I need to extract certain information from a text file and then store this information in another file.
What would be the best way to do this - some sample code would be much appreciated!

 

[meadandale]

String file1 = "file1.txt";
String file2 = "file2.txt";

FileInputStream in = new FileInputStream(file1);
FileOuputStream out = new FileOutputStream(file2);

int c;
while ((c = in.read()) != -1)
out.write(c);

in.close();
out.close();

Note that the above does not include any exception handling or any buffering but simply reads input and writes it out to a new file.

I strongly suggest that you browse the java I/O API.

Charles

 

[Guest_imported]

thats great, thanx!

 

[Guest_imported]

Can you please tell me why the following code will not compile??

I get compiler errors saying "illegal escape character" pointing at - File file = new File("C:\Windows\Documents and Settings\citemp1\My Documents\My Documents\test.doc"

and with

File file2 = new File("C:\JAVA\Test\test1.txt"

see code below!!
============================================================


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

public class Test
{
public static void main(String[] args)
{
try
{
LinkedList myList = new LinkedList( );
File file = new File("C:\Windows\Documents and Settings\citemp1\My Documents\My Documents\test.doc"

Bufferedreader reader = new BufferedReader( new FileReader(File) );

String str = "";
while( (str = reader.readLine( )) != null )
{
myList.add( str );
}
File file2 = new File("C:\JAVA\Test\test1.txt"
PrintWriter writer = new PrintWriter( new BufferedWriter( new FileWriter( file2 ) ) );

Iterator iter = myList.iterator();
while(iter.hasNext())
{ String str1 = (String) iter.next();
if(str1.equals("1&quot )
{ writer.print(str1);
}
}
}
catch( Exception e )
{
System.out.println("ERROR"
}

}
}

============================================================

Thanx

 

[meadandale]

In Java, you have to use unix style path names or use double slashes:

"C:/Java/Test/test1.txt"

or

"C:\\Java\\Test\\test1.txt"

 

[Guest_imported]

Thank you.

Ok...my code now compiles and runs but it catches an error instead of doing what I want it to do.

I'm just doing a test but it catches the exception. Do you think my try block is doing what I want it to do. I have attached a 'buffer reader' to a 'file reader' so that the whole file is read into a buffer.

So when my file is read into the buffer I want to go through the buffer and when I come to some particular text I want to output something in another file.

see code below
============================================================

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

public class Test
{
public static void main(String[] args)
{
try
{

LinkedList myList = new LinkedList( );
File file = new File("C:\\Windows\\Documents and Settings\\citemp1\\My Documents\\My Documents\\test.doc"

BufferedReader reader = new BufferedReader( new FileReader(file) );

/*
Here's the nice part. When the reader gets to the end of a file
i.e. the EOF char. It returns null )
*/
String str = "";
while( (str = reader.readLine( )) != null )
{
myList.add( str );
}
File file2 = new File("C:\\JAVA\\Test\\test1.txt"
PrintWriter writer = new PrintWriter( new BufferedWriter( new FileWriter( file2 ) ) );

Iterator iter = myList.iterator();
while(iter.hasNext())
{ String str1 = (String) iter.next();
if(str1.equals("xyz&quot )
{ writer.print("Test successful"
}
}
}
catch( Exception e )
{
System.out.println("ERROR"
}

}
}

============================================================
Thanks in advance

 

[meadandale]

Try doing:

catch (Exception e) {
e.printStackTrace();
}

so we can find out what the problem is.

 

[Guest_imported]

Ok - here is what it says after runing it!!

============================================================

java.io.FileNotFoundException: C:\Windows\Documents and Settings\citemp1\My Docu
ments\My Documents\test.doc (The system cannot find the path specified)
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.<init>(FileInputStream.java:103)
at java.io.FileReader.<init>(FileReader.java:51)
at Test.main(Test.java:17)
============================================================

 

[Guest_imported]

Ok...my fault..I got the path wrong (stupid mistake!!)

Ok...now it runs and creates the file (test1.txt) but it
doesn't wite to it when I want it to!

I beleive the problem area with my code is as below

============================================================

PrintWriter writer = new PrintWriter( new BufferedWriter( new FileWriter( file2 ) ) );

Iterator iter = myList.iterator();
while(iter.hasNext())
{ String str1 = (String) iter.next();
if(str1.equals(&quot;9&quot )
{ writer.print(&quot;Test successful&quot;
}
}

============================================================

Thanx again

 

[fathima]

hi
i am kind of new to java and i would like to know how i can read a text file with each line containing numbers and words and then get the program to display all the word on each line in reverse order

some sample codes would help a lot as i have been trying to figure this out for the last 2 weeks

thankyou

 

[wushutwist]

Wrap a BufferedReader around a FileReader. This will give you the ability to read line by line. Next you will want to use a StringTokenizer to break up each line into separate words. Displaying these in reverse order should then be a piece of cake to figure out.

Consult Javadocs for more information on how to use the BufferedReader, FileReader, and StringTokenizer classes.