原来Java是这样实现微信小程序加密与解密数据算法的！超赞的有木有？！

<dependency>
    <groupId>org.bouncycastle</groupId>
    <artifactId>bcprov-jdk16</artifactId>
    <version>1.46</version>
</dependency>
 <dependency>
    <groupId>commons-codec</groupId>
    <artifactId>commons-codec</artifactId>
    <version>1.4</version>
</dependency>
<dependency> 
    <groupId>net.sf.json-lib</groupId> 
    <artifactId>json-lib</artifactId> 
    <version>2.2.3</version> 
    <classifier>jdk15</classifier> 
</dependency>

package io.binghe.wechat.crypto.wx;
import java.security.AlgorithmParameters;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.Security;
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 org.bouncycastle.jce.provider.BouncyCastleProvider;
/**
 * AES加密
 * @author binghe
 *
 */
public class AES {
  public static boolean initialized = false;
  /**
   * AES解密
   * 
   * @param content
   *            密文
   * @return
   * @throws InvalidAlgorithmParameterException
   * @throws NoSuchProviderException
   */
  public byte[] decrypt(byte[] content, byte[] keyByte, byte[] ivByte) throws InvalidAlgorithmParameterException {
    initialize();
    try {
      Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
      Key sKeySpec = new SecretKeySpec(keyByte, "AES");
      cipher.init(Cipher.DECRYPT_MODE, sKeySpec, generateIV(ivByte));// 初始化
      byte[] result = cipher.doFinal(content);
      return result;
    } catch (NoSuchAlgorithmException e) {
      e.printStackTrace();
    } catch (NoSuchPaddingException e) {
      e.printStackTrace();
    } catch (InvalidKeyException e) {
      e.printStackTrace();
    } catch (IllegalBlockSizeException e) {
      e.printStackTrace();
    } catch (BadPaddingException e) {
      e.printStackTrace();
    } catch (NoSuchProviderException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } catch (Exception e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
    return null;
  }
  public static void initialize() {
    if (initialized)
      return;
    Security.addProvider(new BouncyCastleProvider());
    initialized = true;
  }
  // 生成iv
  public static AlgorithmParameters generateIV(byte[] iv) throws Exception {
    AlgorithmParameters params = AlgorithmParameters.getInstance("AES");
    params.init(new IvParameterSpec(iv));
    return params;
  }
}

package io.binghe.wechat.crypto.wx;
import java.nio.charset.Charset;
import java.util.Arrays;
/**
 * 微信小程序加解密
 * @author binghe
 *
 */
public class WxPKCS7Encoder {
  private static final Charset CHARSET = Charset.forName("utf-8");
  private static final int BLOCK_SIZE = 32;
  /**
   * 获得对明文进行补位填充的字节.
   *
   * @param count
   *            需要进行填充补位操作的明文字节个数
   * @return 补齐用的字节数组
   */
  public static byte[] encode(int count) {
    // 计算需要填充的位数
    int amountToPad = BLOCK_SIZE - (count % BLOCK_SIZE);
    if (amountToPad == 0) {
      amountToPad = BLOCK_SIZE;
    }
    // 获得补位所用的字符
    char padChr = chr(amountToPad);
    String tmp = new String();
    for (int index = 0; index < amountToPad; index++) {
      tmp += padChr;
    }
    return tmp.getBytes(CHARSET);
  }
  /**
   * 删除解密后明文的补位字符
   *
   * @param decrypted
   *            解密后的明文
   * @return 删除补位字符后的明文
   */
  public static byte[] decode(byte[] decrypted) {
    int pad = decrypted[decrypted.length - 1];
    if (pad < 1 || pad > 32) {
      pad = 0;
    }
    return Arrays.copyOfRange(decrypted, 0, decrypted.length - pad);
  }
  /**
   * 将数字转化成ASCII码对应的字符，用于对明文进行补码
   *
   * @param a
   *            需要转化的数字
   * @return 转化得到的字符
   */
  public static char chr(int a) {
    byte target = (byte) (a & 0xFF);
    return (char) target;
  }
}

package io.binghe.wechat.crypto.wx;
import org.apache.commons.codec.binary.Base64;
import net.sf.json.JSONObject;
/**
 * 封装对外访问方法
 * @author binghe
 *
 */
public class WXCore {
  private static final String WATERMARK = "watermark";
  private static final String APPID = "appid";
  /**
   * 解密数据
   * @return
   * @throws Exception
   */
  public static String decrypt(String appId, String encryptedData, String sessionKey, String iv){
    String result = "";
    try {
      AES aes = new AES();  
        byte[] resultByte = aes.decrypt(Base64.decodeBase64(encryptedData), Base64.decodeBase64(sessionKey), Base64.decodeBase64(iv));  
        if(null != resultByte && resultByte.length > 0){  
            result = new String(WxPKCS7Encoder.decode(resultByte));  
          JSONObject jsonObject = JSONObject.fromObject(result);
          String decryptAppid = jsonObject.getJSONObject(WATERMARK).getString(APPID);
          if(!appId.equals(decryptAppid)){
            result = "";
          }
          }  
    } catch (Exception e) {
      result = "";
      e.printStackTrace();
    }
      return result;
  }
  public static void main(String[] args) throws Exception{
     String appId = "wx4f4bc4dec97d474b";
     String encryptedData = "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";
     String sessionKey = "tiihtNczf5v6AKRyjwEUhQ==";
     String iv = "r7BXXKkLb8qrSNn05n0qiA==";
       System.out.println(decrypt(appId, encryptedData, sessionKey, iv));
    }
}

{"openId":"oGZUI0egBJY1zhBYw2KhdUfwVJJE","nickName":"Band","gender":1,"language":"zh_CN","city":"Guangzhou","province":"Guangdong","country":"CN","avatarUrl":"http://wx.qlogo.cn/mmopen/vi_32/aSKcBBPpibyKNicHNTMM0qJVh8Kjgiak2AHWr8MHM4WgMEm7GFhsf8OYrySdbvAMvTsw3mo8ibKicsnfN5pRjl1p8HQ/0","unionId":"ocMvos6NjeKLIBqg5Mr9QjxrP1FA","watermark":{"timestamp":1477314187,"appid":"wx4f4bc4dec97d474b"}