has not used springMVC, is it estimated that this 302 is sent in sendRedirect? take a look at the source code of this function, you will know

you take a look at the names sendRedirect and setStatus . Send is sent, and sendRedirect will send the response directly to the user, so it is useless for you to set the status code of the response later, and the response has been sent back to the client.

according to the problem description, the implementation in sendRedirect should look like this

function sendRedirect(url) {
    this.statusCode = 302;
    this.setHeader('Location', url);
}

and the implementation of setStatus is like this

function setStatus(code) {
    if(!this.statusCode) {
        this.statusCode = code;
    }
}