The getMessageDigest() method of java.security.DigestOutputStream class provides the MessageDigest assigned to this DigestOutputStream object.
Syntax:
public MessageDigest getMessageDigest()
Return Value: This method returns MessageDigest object assigned to it.
Note : All the programs in this article won’t run on online IDE as no ‘name’ file exists. You can check this code on Java compiler on your system. To check this code, create a file ‘name’ on your system.
Below are the examples to illustrate the getMessageDigest() method:
Example 1:
Java
// Java program to demonstrate// getMessageDigest() methodimport java.security.*;import java.util.*;import java.io.*;public class GFG { public static void main(String[] argv) { try { // creating the object of MessageDigest // and getting instance // By using getInstance() method MessageDigest sr = MessageDigest.getInstance("MD5"); // creating and initializing // object of OutputStream OutputStream is = new FileOutputStream("f:/java/name.txt"); // creating and initializing // object of DigestOutputStream DigestOutputStream di = new DigestOutputStream(is, sr); // getting the message digest // using getMessageDigest() method MessageDigest str = di.getMessageDigest(); // display the result System.out.println("Status : " + str.toString()); } catch (NoSuchAlgorithmException e) { System.out.println("Exception thrown : " + e); } catch (NullPointerException e) { System.out.println("Exception thrown : " + e); } catch (FileNotFoundException e) { System.out.println("Exception thrown : " + e); } }} |
Output:
Status : MD5 Message Digest from SUN,
Example 2:
Java
// Java program to demonstrate// getMessageDigest() methodimport java.security.*;import java.util.*;import java.io.*;public class GFG { public static void main(String[] argv) { try { // creating the object of MessageDigest // and getting instance // By using getInstance() method MessageDigest sr = MessageDigest.getInstance("SHA-1"); // creating and initializing // object of OutputStream OutputStream is = new FileOutputStream("f:/java/name.txt"); // creating and initializing // object of DigestOutputStream DigestOutputStream di = new DigestOutputStream(is, sr); // getting the message digest // using getMessageDigest() method MessageDigest str = di.getMessageDigest(); // display the result System.out.println("Status : " + str.toString()); } catch (NoSuchAlgorithmException e) { System.out.println("Exception thrown : " + e); } catch (NullPointerException e) { System.out.println("Exception thrown : " + e); } catch (FileNotFoundException e) { System.out.println("Exception thrown : " + e); } }} |
Output:
Status : SHA-1 Message Digest from SUN,
Reference: https://docs.oracle.com/javase/9/docs/api/java/security/DigestOutputStream.html#getMessageDigest–
