Weblogic上的Ajax上传文件

I have a problem during web service call (ajax). I put an excel file in parameter but the controller can't get it (null). I checked data before the call and it's ok :

Here the controller :

And here the log from Weblogic server :

There is no problem when I try with Tomcat server included in Spring Boot. This problem comes after deployment on Weblogic.

Do you have an idea ?

Many thanks !