修复算数验证码生成BUG

xtools-app-sys/xtools-app-sys-biz/src/main/java/xtools/app/sys/service/impl/SysLoginServiceImpl.java

@@ -145,7 +145,11 @@ public class SysLoginServiceImpl implements SysLoginService {
         redisService.set(cacheParam.key(uid), arithmeticDto.getResult(), cacheParam.expireTime());
 
         // 转换为base64的验证码
-        return "data:image/png;base64," + new String(Base64Utils.encode(imgCode) == null ? new byte[0] : imgCode);
+        byte[] encode = Base64Utils.encode(imgCode);
+        if (BytesUtils.isEmpty(encode)) {
+            throw new BizError("验证码生成失败");
+        }
+        return "data:image/png;base64," + new String(encode);
     }
 
     /**