Compare the content of 2 text files in java language

Question

please help me to make the code

package utils;

import java.io.*;

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

 FileInputStream file1 = new InputStream(args[0]);
 FileInputStream file2 = new InputStream(args[1]);

 try {
 if(args.length != 2)
  throw (new RuntimeException("Usage : java compare <filetoread> <filetoread>"));


                while (true) {
                   int a = file1.read();
                   int b = file2.read();
                   if (a==-1) { 
                   System.out.println("Files match"); 
                   }
                   else{
                   System.out.println("Files do not match");
                   }
                }

 }
 catch (IOException ioe) {
  System.out.println("Error: " + ioe);
 }
 catch (Exception e) {
  System.out.println("Error: " + e);
 }

}

}

Answer 1

The simplest way is to read the contents into two strings e.g.

  FileInputStream fin =  new FileInputStream(args[i]);
  BufferedReader myInput = new BufferedReader
              (new InputStreamReader(fin));
  StringBuilder sb = new StringBuilder();
  while ((thisLine = myInput.readLine()) != null) {  
             sb.append(thisLine);
  }

, and perform a .equals() on these. Do you require more complex differencing capabilities ?

Answer 2

Read the contents of the files and use the MessageDigest class to create an MD5 hash of the contents of each file. Then compare the two hashes. This has the advantage of working for binary files as well.