C #和Java中的SHA-256哈希

在C#中，可以使用System.Security.Cryptography命名空间中的SHA256Managed类来计算SHA-256哈希。以下是一个计算SHA-256哈希的示例代码：

using System;
using System.Security.Cryptography;
using System.Text;

public class Program
{
    public static void Main(string[] args)
    {
        string input = "Hello World!";
        byte[] hash = CalculateSHA256Hash(input);
        string hashString = ByteArrayToString(hash);
        
        Console.WriteLine("SHA-256 Hash: " + hashString);
    }
    
    public static byte[] CalculateSHA256Hash(string input)
    {
        using (SHA256 sha256 = SHA256.Create())
        {
            byte[] inputBytes = Encoding.UTF8.GetBytes(input);
            byte[] hashBytes = sha256.ComputeHash(inputBytes);
            return hashBytes;
        }
    }
    
    public static string ByteArrayToString(byte[] bytes)
    {
        StringBuilder builder = new StringBuilder();
        for (int i = 0; i < bytes.Length; i++)
        {
            builder.Append(bytes[i].ToString("x2"));
        }
        return builder.ToString();
    }
}

在Java中，可以使用java.security.MessageDigest类来计算SHA-256哈希。以下是一个计算SHA-256哈希的示例代码：

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class Main {
    public static void main(String[] args) {
        String input = "Hello World!";
        byte[] hash = calculateSHA256Hash(input);
        String hashString = bytesToHex(hash);
        
        System.out.println("SHA-256 Hash: " + hashString);
    }
    
    public static byte[] calculateSHA256Hash(String input) {
        try {
            MessageDigest digest = MessageDigest.getInstance("SHA-256");
            byte[] inputBytes = input.getBytes();
            byte[] hashBytes = digest.digest(inputBytes);
            return hashBytes;
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
            return null;
        }
    }
    
    public static String bytesToHex(byte[] bytes) {
        StringBuilder builder = new StringBuilder();
        for (byte b : bytes) {
            builder.append(String.format("%02x", b));
        }
        return builder.toString();
    }
}

这两个示例代码分别使用C#和Java来计算给定字符串的SHA-256哈希，并将结果打印出来。