Java Program: Compare two text files

Today while managing the comments, I got a request of this sort.

HI,

I have a small question in java.
I have two inputs , which are in two documents .I want to compare these two document values. Is it possible in Java.  please let me know.

thanks & Regards,

Certainly, there are ways to compare two text files in Java but the return value can be of many types.

A Java file difference utility can

• compare files character by character.
• give the number of differences between 2 files.
• ignore white space when comparing.

Our program will prompt for 2 file names (.txt) that are to be compared. Given the file names, this program will compare the two files. If any difference is there, it will print the differences and no. of differences in command prompt. If no difference is there, it will print files are equal.

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

public class myfilereader
{
public static void main (String[] args) throws java.io.IOException
{
//Getting the name of the files to be compared.
BufferedReader br2 = new BufferedReader (new
InputStreamReader(System.in));
System.out.println(”Enter 1st File name:”);
String str = br2.readLine();
System.out.println(”Enter 2nd File name:”);
String str1 = br2.readLine();

String s1=”";
String s2=”",s3=”",s4=”";
String y=”",z=”";

//Reading the contents of the files
BufferedReader br = new BufferedReader (new FileReader (str));
BufferedReader br1 = new BufferedReader (new FileReader (str1));

while((z=br1.readLine())!=null)
s3+=z;

while((y=br.readLine())!=null)
s1+=y;

System.out.println ();

//String tokenizing
int numTokens = 0;
StringTokenizer st = new StringTokenizer (s1);
String[] a = new String[10000];
for(int l=0;l<10000;l++)
{a[l]=”";}
int i=0;
while (st.hasMoreTokens())
{
s2 = st.nextToken();
a[i]=s2;
i++;
numTokens++;
}

int numTokens1 = 0;
StringTokenizer st1 = new StringTokenizer (s3);
String[] b = new String[10000];
for(int k=0;k<10000;k++)
{b[k]=”";}
int j=0;
while (st1.hasMoreTokens())
{
s4 = st1.nextToken();
b[j]=s4;
j++;
numTokens1++;
}

//comparing the contents of the files and printing the differences, if any.
int x=0;
for(int m=0;m<a.length;m++)
{
if(a[m].equals(b[m])){}
else
{
x++;
System.out.println(a[m] + ” — ” +b[m]);
System.out.println();}
}
System.out.println(”No. of differences : ” + x);
if(x>0){System.out.println(”Files are not equal”);}
else{System.out.println(”Files are equal. No difference found”);}

}
}

[code source: sourcecodesworld.com]

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