https://developers.weixin.qq.com/miniprogram/dev/framework/server-ability/message-push.html 这篇文章里提到的AES加密策略为 AES/CBC/PKCS7Padding，实测无法解密。下载文中提供的SDK，其中的策略为 AES/CBC/NoPadding，实测可以成功解密。另外原文缺少对iv参数的描述，希望完善。

附针对当前文档提供的示例明文、密文，可得出正确结果的Java解密代码：

import cn.hutool.core.codec.Base64;
import cn.hutool.core.map.MapUtil;
import cn.hutool.core.util.ArrayUtil;
import cn.hutool.crypto.symmetric.AES;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.codec.digest.DigestUtils;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.*;

import javax.crypto.spec.IvParameterSpec;
import java.util.Arrays;
import java.util.Map;


/**
 * 接收消息推送，解密方式为安全模式
 */
@PostMapping
public static String receive(@RequestParam("signature") String signature,
                             @RequestParam("timestamp") String timestamp,
                             @RequestParam("nonce") String nonce,
                             @RequestParam("openid") String openid,
                             @RequestParam("encrypt_type") String encryptType,
                             @RequestParam("msg_signature") String msgSignature,
                             @RequestBody Map requestBody) {
    log.info("收到微信小程序消息推送：signature={}, timestamp={}, nonce={}, openid={}, encrypt_type={}, msg_signature={}, requestBody={}",
            signature, timestamp, nonce, openid, encryptType, msgSignature, requestBody);
    /*
    请求报文体示例：
    {
        "ToUserName": "gh_97417a04a28d",
        "Encrypt": "+qdx1OKCy+5JPCBFWw70tm0fJGb2Jmeia4FCB7kao+/Q5c/ohsOzQHi8khUOb05JCpj0JB4RvQMkUyus8TPxLKJGQqcvZqzDpVzazhZv6JsXUnnR8XGT740XgXZUXQ7vJVnAG+tE8NUd4yFyjPy7GgiaviNrlCTj+l5kdfMuFUPpRSrfMZuMcp3Fn2Pede2IuQrKEYwKSqFIZoNqJ4M8EajAsjLY2km32IIjdf8YL/P50F7mStwntrA2cPDrM1kb6mOcfBgRtWygb3VIYnSeOBrebufAlr7F9mFUPAJGj04="
    }
     */
    String encrypt = MapUtil.getStr(requestBody, "Encrypt");

    // 验签
    // 将三个值按字典值排序拼接
    String token = "AAAAA";
    String[] strings = {token, timestamp, nonce, encrypt};
    Arrays.sort(strings);
    String textToSign = ArrayUtil.join(strings, "");
    // 验签
    boolean verify = DigestUtils.sha1Hex(textToSign).equals(msgSignature);
    log.info("验签结果：{}", verify);
    if (!verify) {
        return null;
    }

    // 解密消息
    String encodingAesKey = "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
    byte[] aesKey = Base64.decode(encodingAesKey + "=");
    byte[] tmpMsg = Base64.decode(encrypt);

    IvParameterSpec iv = new IvParameterSpec(Arrays.copyOfRange(aesKey, 0, 16));
    AES aes = new AES("CBC", "NoPadding", aesKey, iv.getIV());
    // fullStr结构：random(16B) + msg_len(4B) + msg + appid，其中
    // random(16B)为 16 字节的随机字符串；
    final int randomPartSize = 16;
    // msg_len 为 msg 长度，占 4 个字节(网络字节序)；
    final int msgLenPartSize = 4;
    // msg为明文；
    // appid为小程序Appid。
    byte[] fullStr = trimPadding(aes.decrypt(tmpMsg));
    // 删除明文补位字符
    String random = new String(Arrays.copyOfRange(fullStr, 0, randomPartSize));
    int msgLen = ByteBuffer.wrap(Arrays.copyOfRange(fullStr, randomPartSize, randomPartSize + msgLenPartSize)).getInt();
    String msg = new String(Arrays.copyOfRange(fullStr, randomPartSize + msgLenPartSize, randomPartSize + msgLenPartSize + msgLen));;
    String appid = new String(Arrays.copyOfRange(fullStr, randomPartSize + msgLenPartSize + msgLen, fullStr.length));;

    log.info("解密结果：random={}, msg_len={}, msg={}, appid={}", random, msgLen, msg, appid);

    // 如无特殊要求一般返回空或success，其他内容则需要加密返回
    return "success";
}

/**
 * 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
 */
private static byte[] trimPadding(byte[] decrypted) {
    int pad = decrypted[decrypted.length - 1];
    if (pad < 1 || pad > 32) {
        pad = 0;
    }
    return Arrays.copyOfRange(decrypted, 0, decrypted.length - pad);
}

public static void main(String[] args) {
    String signature = "6c5c811b55cc85e0e1b54100749188c20beb3f5d";
    String timestamp = "1714112445";
    String nonce = "415670741";
    String openid = "o9AgO5Kd5ggOC-bXrbNODIiE3bGY";
    String encryptType = "aes";
    String msgSignature = "046e02f8204d34f8ba5fa3b1db94908f3df2e9b3";
    Map requestBody = MapUtil.newHashMap();
    requestBody.put("ToUserName", "gh_97417a04a28d");
    requestBody.put("Encrypt", "+qdx1OKCy+5JPCBFWw70tm0fJGb2Jmeia4FCB7kao+/Q5c/ohsOzQHi8khUOb05JCpj0JB4RvQMkUyus8TPxLKJGQqcvZqzDpVzazhZv6JsXUnnR8XGT740XgXZUXQ7vJVnAG+tE8NUd4yFyjPy7GgiaviNrlCTj+l5kdfMuFUPpRSrfMZuMcp3Fn2Pede2IuQrKEYwKSqFIZoNqJ4M8EajAsjLY2km32IIjdf8YL/P50F7mStwntrA2cPDrM1kb6mOcfBgRtWygb3VIYnSeOBrebufAlr7F9mFUPAJGj04=");
    System.out.println(receive(signature, timestamp, nonce, openid, encryptType, msgSignature, requestBody));
}