奇怪的是我这总报pad block corrupted

java基本上github上能搜出一大堆大三方库帮你把整个流程都写好了。

实在要demo，那就

调用code2session之后的解密无非就是调用下Cipher

通过code调用code2session获得的sessionKey，用户请求进来iv和encryptedData

try {
  /* <dependency>
   *   <groupId>org.bouncycastle</groupId>
   *   <artifactId>bcprov-jdk16</artifactId>
   *   <version>1.46</version>
   * </dependency>
   */
  Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding", new BouncyCastleProvider());
  SecretKeySpec key = new SecretKeySpec(Base64.decode(sessionKey), "AES");
  IvParameterSpec ivParameterSpec = new IvParameterSpec(
          Base64.decode(iv)
  );
  cipher.init(Cipher.DECRYPT_MODE, key, ivParameterSpec);
  byte[] encryptedDataBytes = Base64.decode(encryptedData);
  byte[] result = cipher.doFinal(encryptedDataBytes);
  // 解密后的JSON
  String json = new String(result, "UTF-8");
  // 然后该干嘛干嘛
} 
  catch (Exception e) {
  // ...
}

嗯，就酱紫。