如果您已经在使用Apache DigestUtils类，请用途：

String hex256 = new DigestUtils(MessageDigestAlgorithms.SHA_256)
    .digestAsHex(bytes);

下面的代码生成的哈希值与sha256sum对包含相同字符串的文本文件所做的哈希值相同：

import java.util.List;
import java.util.HexFormat;
import java.util.stream.Collectors;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;

public class Hash256 {
    public static void main(String[] args) {
        try {
            List<String> strings = List.of("alpha", "beta", "gamma");
            final String SEP = "\n";
            MessageDigest digest = MessageDigest.getInstance("SHA-256");
            String originalString = strings.stream()
                .collect(Collectors.joining(SEP));
            originalString += SEP;
            byte[] encodedHash = digest.digest(originalString.getBytes(StandardCharsets.UTF_8));
            System.out.println(HexFormat.of().formatHex(encodedHash));
        } catch (Throwable t) {
            t.printStackTrace();
        }
    }
}