解析微信小程序手機號及異常（Given final block not properly padded.）

Exception:javax.crypto.BadPaddingException: Given final block not properly padded. Such issues can arise if a bad key is used during decryption.

偶發性異常：沒登錄時用AES/CBC/PKCS7Padding，登錄后用AES/CBC/PKCS5Padding；

原因 : 微信小程序的sessionKey有一個過期時間5分鍾;

解決 : 使用工具封裝

import com.alibaba.fastjson.JSONObject;
import org.springframework.stereotype.Component;
import org.springframework.util.Base64Utils;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.AlgorithmParameterSpec;


@Component
public class WxMiniPhoneAnalysis {

   
    public static String getWxMiniPhone(String sessionkey, String iv, String encryptedData)
            throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidAlgorithmParameterException,
            InvalidKeyException, BadPaddingException, IllegalBlockSizeException, UnsupportedEncodingException {

        byte[] encrypData = Base64Utils.decodeFromString(encryptedData);
        byte[] ivData = Base64Utils.decodeFromString(iv);
        byte[] sessionKey = Base64Utils.decodeFromString(sessionkey);
        String resultString = null;
        AlgorithmParameterSpec ivSpec = new IvParameterSpec(ivData);
        SecretKeySpec keySpec = new SecretKeySpec(sessionKey, "AES");
        try {
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
            cipher.init(Cipher.DECRYPT_MODE, keySpec, ivSpec);
            resultString = new String(cipher.doFinal(encrypData), "UTF-8");
        } catch (Exception e) {
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
            cipher.init(Cipher.DECRYPT_MODE, keySpec, ivSpec);
            resultString = new String(cipher.doFinal(encrypData), "UTF-8");
        }
        JSONObject object = JSONObject.parseObject(resultString);
        // 拿到手機號碼
        String phone = object.getString("phoneNumber");
        return phone;
    }
}

源自：
https://www.it610.com/article/1283039259715977216.htm
https://developers.weixin.qq.com/community/develop/doc/0002ccdd28c1a0f852f84e3bf56400