Is it possible to merge two (or more) text files together using Java, and if so, how would it be done? I really don't want to have to resort to copy and pasting everything over as both files are quite large, but I haven't been able to find any code or information about it on the internet.

For example, assume the first text file looks like this:

A1
B1
C1

And the second looks like this:

2
3
4

I'd like to merge them together to look something like this:

A12
B13
C14

To point you toward the right direction, you could open two input streams (one for each text file), read a line of the first one, then a line from the second one, concat them together and print the result in the new text file using a print stream.

Something like this? The code isn't compiling correctly, but I think I'm on the right track. Any help would be appreciated!

[You are on the right track indeed....

But you have to remove your definition of temp1 and temp2 out of the while so they will be seeen out of he loop



and also

Thanks, PBL! That took away some of the errors. I'm still getting errors around the BufferedReader lines ("Can't find ( or ]") and the temp.length line (It's highlighting .length, and saying it 'can't find symbol'), and I don't quite understand why this is happening. Here's my code at the moment:

What you are doing is reading all file1 then all file2 cumulating them in temp1 and temp2
that is not what you want, you want it line per line
3 typos and unhandled exception
FileWriter has a method to write a String no need to convert into a char[]
This should do the trick

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;

public class Main {


	public static void main(String[] args) {
		try {
			FileReader file1=new FileReader("Data1.txt");
			FileReader file2=new FileReader("Data2.txt");
			BufferedReader br1 = new BufferedReader(file1);   // remove the "of"
			BufferedReader br2 = new BufferedReader(file2);   // removed the "of"
			FileWriter fw=new FileWriter("data3.txt");
			
			String temp1, temp2;
			temp1 = br1.readLine();
			while(temp1 != null) {
				temp2 = br2.readLine();
				fw.write(temp1 + temp2);
				// read next line
			    temp1 = br1.readLine();
			}
			file1.close();
			file2.close();
			fw.close();
		}
		catch (Exception e) {
           System.out.println("Error opening/reading/writing file: " + e);
		}

	}
}

Have fun... I am not sure about the write(String) method in a FileWriter may be (I said MAY BE) you have to add a new line at the end of the line so it would be

fw.write(temp1 + temp2 + "\n");


This post has been edited by pbl: 1 May, 2008 - 11:39 AM

Hey i hv used your codes but i found errors in them......
so i hv corrected them n the code is
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
public class main1 {
public static void main(String[] args) {
try {
FileReader f1=new FileReader("b.txt");
FileReader f2=new FileReader("c.txt");
BufferedReader br1 = new BufferedReader(f1);
BufferedReader br2 = new BufferedReader(f2);
FileWriter x=new FileWriter("d.txt");
String a, b;
a = br1.readLine();
while(a != null) {
b = br2.readLine();
x.write(a + b+" ");
a = br1.readLine();
}

f1.close();
f2.close();
x.close(); }
catch (Exception e) {
System.out.println("Error opening/reading/writing file: " + e);
}
}
}

Plz anyone help me to Get the output in Column wise..............
Reply as sonn as possible........

This post has been edited by pratik.96: 3 Jul, 2009 - 10:55 PM