微信小程序获取用户信息，解密encryptedData 包括敏感数据在内的完整用户信息的加密数据

package com.iups.wx.wxservice;

import java.io.UnsupportedEncodingException;
import java.security.AlgorithmParameters;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.Security;
import java.security.spec.InvalidParameterSpecException;
import java.util.HashMap;
import java.util.Map;

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 net.sf.json.JSONObject;

import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.util.Arrays;
import org.codehaus.xfire.util.Base64;

import com.iups.wx.common.RemoteInterfaceAddress;
import com.iups.wx.util.HttpsClientUtil;

/**
 * 微信小程序信息获取
 * @author Administrator
 * @Date 2017年2月16日 11:56:08
 */
public class WXAppletUserInfo {

    /**
     * 获取微信小程序 session_key 和 openid
     * @param code
     * @return
     */
    public JSONObject getSessionKeyOropenid(String code){
        //微信端登录code值
        String wxCode = code;
        String requestUrl = RemoteInterfaceAddress.GETSESSIONKEYOROPENID;
        Map<String,String> requestUrlParam = new HashMap<String,String>();
        requestUrlParam.put("appid", RemoteInterfaceAddress.AppletAPPID);
        requestUrlParam.put("secret", RemoteInterfaceAddress.AppletAppSecret);
        requestUrlParam.put("js_code", wxCode);
        requestUrlParam.put("grant_type", "authorization_code");
        JSONObject jsonObject = HttpsClientUtil.getInstance().sendGetRequest(requestUrl, requestUrlParam);
        return jsonObject;
    }

    /**
     * 解密用户敏感数据获取用户信息
     * @param sessionKey 数据进行加密签名的密钥
     * @param encryptedData 包括敏感数据在内的完整用户信息的加密数据
     * @param iv 加密算法的初始向量
     * @return
     */
    public JSONObject getUserInfo(String encryptedData,String sessionKey,String iv){
        // 被加密的数据
        byte[] dataByte = Base64.decode(encryptedData);
        // 加密秘钥
        byte[] keyByte = Base64.decode(sessionKey);
        // 偏移量
        byte[] ivByte = Base64.decode(iv);

        try {
               // 如果密钥不足16位，那么就补足.  这个if 中的内容很重要
            int base = 16;
            if (keyByte.length % base != 0) {
                int groups = keyByte.length / base + (keyByte.length % base != 0 ? 1 : 0);
                byte[] temp = new byte[groups * base];
                Arrays.fill(temp, (byte) 0);
                System.arraycopy(keyByte, 0, temp, 0, keyByte.length);
                keyByte = temp;
            }
            // 初始化
            Security.addProvider(new BouncyCastleProvider());
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding","BC");
            SecretKeySpec spec = new SecretKeySpec(keyByte, "AES");
            AlgorithmParameters parameters = AlgorithmParameters.getInstance("AES");
            parameters.init(new IvParameterSpec(ivByte));
            cipher.init(Cipher.DECRYPT_MODE, spec, parameters);// 初始化
            byte[] resultByte = cipher.doFinal(dataByte);
            if (null != resultByte && resultByte.length > 0) {
                String result = new String(resultByte, "UTF-8");
                return JSONObject.fromObject(result);
            }
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (InvalidParameterSpecException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (InvalidAlgorithmParameterException e) {
            e.printStackTrace();
        } catch (NoSuchProviderException e) {
            e.printStackTrace();
        }
        return null;
    }

}