Java SHA-256 Hash using Apache Commons Codec

Tags: Apache Commons Codec Java SHA-256 Java Hash DigestUtils

In this Java tutorial we learn how to calculate the SHA-256 digest in Java application using the DigestUtils class of Apache Commons Codec library.

Table of contents

  1. Add Apache Commons Codec Dependency to Java project
  2. Convert String to SHA-256 Hash in Java
  3. Generate File SHA-256 Checksum Hash String in Java
  4. Generate SHA-256 Hash as Bytes Array
  5. Get Instance of java.security.MessageDigest for SHA-256 Hash Algorithm

Add Apache Commons Codec Dependency to Java project

To use Apache Commons Codec library in the Gradle build project, add the following dependency into the build.gradle file. 

implementation group: 'commons-codec', name: 'commons-codec', version: '1.15'

To use the Apache Commons Codec library in the Maven build project, add the following dependency into the pom.xml file. 

<dependency>
    <groupId>commons-codec</groupId>
    <artifactId>commons-codec</artifactId>
    <version>1.15</version>
</dependency>

To have more information about the Apache Commons Codec Java library you can visit the project home page at commons.apache.org/proper/commons-codec/

Convert String to SHA-256 Hash in Java

The Apache Commons Codec library provides method DigestUtils.sha256Hex() can be used to calculate the SHA-256 digest and return value as a hex string. 

String sha256Value = DigestUtils.sha256Hex(inputData);

In the following Java program, we show how to use DigestUtils.sha256Hex() method to hash an input String to SHA-256 hash as a hex string.

Sha256Example1.java 

import org.apache.commons.codec.digest.DigestUtils;

public class Sha256Example1 {
    public static void main(String... args) {
        String inputData = "Simple Solution";

        String sha256Value = DigestUtils.sha256Hex(inputData);

        System.out.println("Input String:" + inputData);
        System.out.println("SHA-256:" + sha256Value);
    }
}
The output as below. 
Input String:Simple Solution
SHA-256:a93913858f405f9edc58f24a5202d687a5961122f1de2ac39c57034ab5c00f9e

Generate File SHA-256 Checksum Hash String in Java

Apache Commons Codec library provides the DigestUtils.sha256Hex() method to generate SHA-256 hash for an InputStream as below. 

String sha256Value = DigestUtils.sha256Hex(inputStream);

For example, we have a document file at D:\SimpleSolution\Document.doc

The following Java program to show you how to use the DigestUtils.sha256Hex() to generate SHA-256 checksum hash for a given file and return SHA-256 hash value as a hex string.

Sha256Example2.java 

import org.apache.commons.codec.digest.DigestUtils;

import java.io.FileInputStream;
import java.io.IOException;

public class Sha256Example2 {
    public static void main(String... args) throws IOException {
        String filePath = "D:\\SimpleSolution\\Document.docx";

        String sha256Value = DigestUtils.sha256Hex(new FileInputStream(filePath));

        System.out.println("SHA-256:" + sha256Value);
    }
}
The output as below. 
SHA-256:ec79b54711691ec3f5d493a2df5fa998eca92a83a457fb21eb5da508e7dcdfc6

Generate SHA-256 Hash as Bytes Array

The Apache Commons Codec library also provides DigestUtils.sha256() method to calculate SHA-256 digest and return value as a byte[] array. 

byte[] sha256Value = DigestUtils.sha256(inputData);

The following Java example program to show you how to use the DigestUtils.sha256() method to hash a String to a SHA-256 hash value as byte[] array.

Sha256Example3.java 

import org.apache.commons.codec.digest.DigestUtils;

import java.util.Arrays;

public class Sha256Example3 {
    public static void main(String... args) {
        String inputData = "Simple Solution";

        byte[] sha256Value = DigestUtils.sha256(inputData);

        System.out.println("Input String:" + inputData);
        System.out.println("SHA-256 as bytes:" + Arrays.toString(sha256Value));
    }
}
The output as below. 
Input String:Simple Solution
SHA-256 as bytes:[-87, 57, 19, -123, -113, 64, 95, -98, -36, 88, -14, 74, 82, 2, -42, -121, -91, -106, 17, 34, -15, -34, 42, -61, -100, 87, 3, 74, -75, -64, 15, -98]

Get Instance of java.security.MessageDigest for SHA-256 Hash Algorithm

Using Apache Commons Codec we can use the DigestUtils.getSha256Digest() method to return instance of SHA-256 java.security.MessageDigest and use it to calculate the SHA-256 hash as following Java program.

Sha256Example4.java 

import org.apache.commons.codec.binary.Hex;
import org.apache.commons.codec.digest.DigestUtils;

import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;

public class Sha256Example4 {
    public static void main(String... args) {
        String inputData = "Simple Solution";

        MessageDigest sha256MessageDigest = DigestUtils.getSha256Digest();
        byte[] hashedBytes = sha256MessageDigest.digest(inputData.getBytes(StandardCharsets.UTF_8));
        String sha256Value = Hex.encodeHexString(hashedBytes);

        System.out.println("Input String:" + inputData);
        System.out.println("SHA-256:" + sha256Value);
    }
}
The output as below. 
Input String:Simple Solution
SHA-256:a93913858f405f9edc58f24a5202d687a5961122f1de2ac39c57034ab5c00f9e

Happy Coding 😊

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