如何在Java中生成HMAC等效于Python示例？

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.util.Base64;

public class HmacExample {
    public static void main(String[] args) {
        String message = "Hello, World!";
        String key = "mySecretKey";

        try {
            // 创建HMAC算法实例，使用SHA-256哈希函数
            Mac hmac = Mac.getInstance("HmacSHA256");

            // 创建密钥对象
            SecretKeySpec secretKey = new SecretKeySpec(key.getBytes(), "HmacSHA256");

            // 初始化HMAC算法实例
            hmac.init(secretKey);

            // 计算消息的HMAC值
            byte[] hmacBytes = hmac.doFinal(message.getBytes());

            // 将HMAC值转换为Base64字符串
            String hmacString = Base64.getEncoder().encodeToString(hmacBytes);

            System.out.println("HMAC: " + hmacString);
        } catch (NoSuchAlgorithmException | InvalidKeyException e) {
            e.printStackTrace();
        }
    }
}