Send data from html to mySql Question

What I want to make is a homepage that stores and prints the name and image in DB when I put it in the homepage.

DB Status

Killer dto (You can think of it as a user)

killer mapper

Input form

Controller

I don't care about the output, but I'm going to send data to mySql now

When I checked with the Get method, I confirmed that killerId was entered normally.

But if you type it and press write, it says killerId is null. If you know how to solve it, please tell me know.