Java中解密微信加密数据工具类

<!-- lombok依赖 -->
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <optional>true</optional>
</dependency>
<!-- alibaba的fastjson -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.60</version>
</dependency>
<!-- 工具包 -->
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.8.1</version>
</dependency>
<!-- rsa加密工具-->
<dependency>
    <groupId>org.bouncycastle</groupId>
    <artifactId>bcprov-jdk15on</artifactId>
    <version>1.55</version>
</dependency>

import com.alibaba.fastjson.JSONObject;
import com.sun.org.apache.xerces.internal.impl.dv.util.Base64;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.AlgorithmParameters;
import java.security.Security;
import java.util.Arrays;

/**
 * 解密微信加密数据工具类
 */
@Slf4j
public class WechatUtils {

    /**
     * 解密微信加密数据
     *
     * @param encryptedData
     * @param iv
     * @param sessionkey
     * @return
     */
    public static JSONObject decryptWechatData(String encryptedData, String iv, String sessionkey) {
        // 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 {
            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;
            }
            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);
            byte[] resultByte = cipher.doFinal(dataByte);
            if (null != resultByte && resultByte.length > 0) {
                String result = new String(resultByte, "UTF-8");
                if (StringUtils.isNotBlank(result)) {
                    log.info("----------解密微信数据成功----------");
                    return JSONObject.parseObject(result);
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
            log.info("----------解密微信数据失败----------");
        }
        return null;
    }
}