PHP如何实现与Java类似的AES加解密效果？

<?php
class AESUtil {
    private static $key = "test"; // 默认密钥

    /**
     * AES加密
     * @param string $content 待加密数据
     * @param string|null $key 密钥，为空则使用默认密钥
     * @return string 十六进制加密结果
     */
    public static function encrypt(string $content, string $key = null): string {
        $key = $key ?? self::$key;
        $iv_size = openssl_cipher_iv_length('AES-128-CBC');
        $iv = openssl_random_pseudo_bytes($iv_size);
        $encrypted = openssl_encrypt($content, 'AES-128-CBC', $key, OPENSSL_RAW_DATA, $iv);
        return bin2hex($iv . $encrypted);
    }

    /**
     * AES解密
     * @param string $content 十六进制加密数据
     * @param string|null $key 密钥，为空则使用默认密钥
     * @return string 解密结果
     */
    public static function decrypt(string $content, string $key = null): string {
        $key = $key ?? self::$key;
        $data = hex2bin($content);
        $iv_size = openssl_cipher_iv_length('AES-128-CBC');
        $iv = substr($data, 0, $iv_size);
        $encrypted = substr($data, $iv_size);
        return openssl_decrypt($encrypted, 'AES-128-CBC', $key, OPENSSL_RAW_DATA, $iv);
    }
}

// 示例
$plaintext = "Hello, World!";
$encrypted = AESUtil::encrypt($plaintext);
$decrypted = AESUtil::decrypt($encrypted);

echo "原文: " . $plaintext . PHP_EOL;
echo "加密后: " . $encrypted . PHP_EOL;
echo "解密后: " . $decrypted . PHP_EOL;
?>