Bad Request on simple POST Request - rest

Question

I have broke it down to a minimum and still don't know why this happens.
I have the following method in my controller:
#RequestMapping(method = RequestMethod.POST, value = "/myGreatCall")
public String getDynamicData(#RequestBody DataRequest dr) {
return dr.toString();
}
Using the following simple class:
public class DataRequest {
private String type;
//Getters and setters here
}
Now if I try to call this, I get an error 400 as the response.
let url = window.location.protocol+"//"+window.location.host+"/myGreatCall";
let request = new XMLHttpRequest();
request.open("POST", url, true);
request.onload = function () {
console.log(request.response); //Here I read the reponse and get the error 404
};
// This is the data I send as the body
let data = JSON.stringify(
{
type: "myType"
}
);
request.setRequestHeader("Content-Type", "application/json");
request.send(data);
Now from the error I suspect that for some reason it cant map my json object into the java object, but I have no idea why.
I tested the following:
do the request without the Method Parameter, that worked
different data types in the java class
handing over a hardcoded string '{\"type\":\"myType\"}' to the #send()
Any Ideas what I might be doing wrong?

Answer 1

It may be down to JSON serialization. Try this:
let data = JSON.stringify(
{
"type": "myType"
}
);

Answer 2

Ok seems to be something weird. I dont know what caused it, but after a PC restart it worked fine.