java 生成 SHA256 十六进制编码签名

以下是 Java 代码示例：

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

public class SHA256Example {
    public static void main(String[] args) throws NoSuchAlgorithmException {
        
        String input = "Hello World!";
        
        // 创建 SHA-256 消息摘要对象
        MessageDigest messageDigest = MessageDigest.getInstance("SHA-256");
        
        // 计算消息摘要
        byte[] hash = messageDigest.digest(input.getBytes());
        
        // 转换成十六进制编码
        StringBuilder hexString = new StringBuilder();
        for (byte b : hash) {
            String hex = Integer.toHexString(0xff & b);
            if (hex.length() == 1) {
                hexString.append('0');
            }
            hexString.append(hex);
        }
        
        String sign = hexString.toString();
        System.out.println(sign);
    }
}

运行结果：

b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9