生成签名

生成数据签名的目的是确保数据的完整性和身份验证。数据签名是通过使用加密算法和密钥对数据进行处理，生成一个唯一的标识，称为签名。这个签名可以用来验证数据在传输或存储过程中是否被篡改过，并且可以确定数据的来源是否合法。

> 注：只有data里面的数据进行了签名，其他数据不进行签名

PHP方法：

php
//生成签名
function generateSignature($params, $secretKey)
{
    // 对参数按照键名进行升序排序
    ksort($params);
    // 构建待签名字符串
    $signString = $this->buildSignString($params);
    // 生成签名
    $signature = hash_hmac('sha256', $signString, $secretKey);
    return $signature;
}

//构建签名字符串
function buildSignString($params, $prefix = '')
{
    $signString = '';
    foreach ($params as $key => $value) {
        if (is_array($value)) {
            // 如果值是数组，则进行递归处理
            $subPrefix = $prefix ? $prefix . '[' . $key . ']' : $key;
            $signString .= $this->buildSignString($value, $subPrefix);
        } else {
            $paramKey = $prefix ? $prefix . '[' . $key . ']' : $key;
            $signString .= $paramKey . '=' . $value . '&';
        }
    }
    return $signString;
}

JAVA 方法：
> 需要第三方依赖 com.google.gson

java
import java.nio.charset.StandardCharsets;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.util.Map;
import java.util.TreeMap;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;

public class SignatureGenerator {

    public String generateSignatureFromJson(String json, String secretKey)
            throws NoSuchAlgorithmException, InvalidKeyException {
        Gson gson = new Gson();
        TypeToken<Map<String, Object>> typeToken = new TypeToken<Map<String, Object>>() {
        };
        Map<String, Object> params = gson.fromJson(json, typeToken.getType());

        TreeMap<String, Object> sortedParams = new TreeMap<>(params);
        String signString = buildSignString(sortedParams, "");
        System.out.println("Sign String: " + signString);
        return calculateHmacSha256(signString, secretKey);
    }

    private String buildSignString(Map<String, Object> params, String prefix) {
        StringBuilder signString = new StringBuilder();
        for (Map.Entry<String, Object> entry : params.entrySet()) {
            String key = entry.getKey();
            Object value = entry.getValue();
            String paramKey = prefix + key;
            if (value instanceof Map) {
                @SuppressWarnings("unchecked")
                Map<String, Object> subParams = (Map<String, Object>) value;
                signString.append(buildSignString(subParams, paramKey + "."));
            } else {
                signString.append(paramKey).append("=").append(value).append("&");
            }
        }
        return signString.toString();
    }

    private String calculateHmacSha256(String data, String secretKey)
            throws NoSuchAlgorithmException, InvalidKeyException {
        Mac hmacSha256 = Mac.getInstance("HmacSHA256");
        SecretKeySpec secretKeySpec = new SecretKeySpec(secretKey.getBytes(StandardCharsets.UTF_8), "HmacSHA256");
        hmacSha256.init(secretKeySpec);
        byte[] hmacBytes = hmacSha256.doFinal(data.getBytes(StandardCharsets.UTF_8));
        StringBuilder hexString = new StringBuilder();
        for (byte hmacByte : hmacBytes) {
            String hex = Integer.toHexString(0xFF & hmacByte);
            if (hex.length() == 1) {
                hexString.append('0');
            }
            hexString.append(hex);
        }
        return hexString.toString();
    }

    public static void main(String[] args) {
        SignatureGenerator signatureGenerator = new SignatureGenerator();

        String json = "{\"appname\":\"默然博客\",\"appicon\":\"http://moranhtpro.cn/android.png\",\"application_introduction\":\"\",\"developer_contact_info\":\"\",\"official_group\":\"\",\"announcement_configuration\":{\"title\":\"\",\"content\":\"\"},\"updates_info\":{\"update_version\":\"1.0\",\"update_url\":\"\",\"update_content\":\"\"},\"app_exten_info\":[]}";
        String secretKey = "osnjZbhHDpartfN9XLBiJSO4xzgKkTy7";
        try {
            String signature = signatureGenerator.generateSignatureFromJson(json, secretKey);
            System.out.println("Signature: " + signature);
        } catch (NoSuchAlgorithmException | InvalidKeyException e) {
            System.out.println("Error: " + e.getMessage());
        }
    }
}