自己的服务解密，获取微信小程序用户的手机号码

1、小程序传参数js_code（用户获取session_key）和encryptedData、vi（用于解密手机号）

发送http请求调接口：

https://api.weixin.qq.com/sns/jscode2session?appid=固定的appid&secret=固定的secret&js_code=每次小程序传参&grant_type=authorization_code

返回数据如下，取出session_key用于解密：

{"session_key":"EKjnfpQ6LFxScbtOg==","expires_in":7200,"openid":"oBEMf0UbSQ6xpgUcI"}

2、拿session_key和encryptedData、vi解密手机号

import org.apache.commons.codec.binary.Base64;
import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.spec.AlgorithmParameterSpec;

/**
 * Created by hgg on 2018/2/24.
 * 小程序AES解密
 */
public class AESDecodeUtils {

    public static void main(String[] args) throws Exception {
        byte[] encrypData = Base64.decodeBase64("mgxuts7uEbdnBclp0Qim0TS3MGoaSyE09MqTvbeG9Z1PjxsDwjVH0FxG1Q==");
        byte[] ivData = Base64.decodeBase64("SG386etdA3sOXHxqfnw==");
        byte[] sessionKey = Base64.decodeBase64("Fn6r4IOiZJBXn4hQ0w==");
        System.out.println(decrypt(sessionKey,ivData,encrypData));
    }

    public static String decrypt(byte[] key, byte[] iv, byte[] encData) throws Exception {
        AlgorithmParameterSpec ivSpec = new IvParameterSpec(iv);
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        SecretKeySpec keySpec = new SecretKeySpec(key, "AES");
        cipher.init(Cipher.DECRYPT_MODE, keySpec, ivSpec);
        //解析解密后的字符串
        return new String(cipher.doFinal(encData),"UTF-8");
    }
}

encryptedData 解密后为以下 json 结构，详见加密数据解密算法

{
    "phoneNumber": "13580006666",  
    "purePhoneNumber": "13580006666", 
    "countryCode": "86",
    "watermark":
    {
        "appid":"APPID",
        "timestamp":TIMESTAMP
    }
}

借鉴文章，感谢！