Example to compute MD5 check sum for the given file using java

MD5  is one of the famous hasing algorithm which are used by majority companies. The following example demonstrates,

how to compute MD5 checksum for the given file which is located in 'C:\' drive

package com.onlinecodegeek.md5.ex;

import java.io.FileInputStream;
import java.security.MessageDigest;

public class MD5CheckSumExample 
{
    public static void main(String[] args)throws Exception
    {
        MessageDigest md = MessageDigest.getInstance("MD5");
        FileInputStream fis = new FileInputStream("C:\\installTuner.log");
        
        byte[] dataBytes = new byte[1024];
     
        int nread = 0; 
        while ((nread = fis.read(dataBytes)) != -1) {
          md.update(dataBytes, 0, nread);
        };
        byte[] mdbytes = md.digest();
     
        //convert the byte to hex format method 1
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < mdbytes.length; i++) {
          sb.append(Integer.toString((mdbytes[i] & 0xff) + 0x100, 16).substring(1));
        }

        System.out.println("Digest(in hex format):: " + sb.toString());
        
        //convert the byte to hex format method 2
        StringBuffer hexString = new StringBuffer();
    	for (int i=0;i<mdbytes.length;i++) {
    		String hex=Integer.toHexString(0xff & mdbytes[i]);
   	     	if(hex.length()==1) hexString.append('0');
   	     	hexString.append(hex);
    	}
    	System.out.println("Digest(in hex format):: " + hexString.toString());
    }
}

Output:

Digest(in hex format):: 296e610b187f506d10bd832c5c411d87 Digest(in hex format):: 296e610b187f506d10bd832c5c411d87

 

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