如何在JSF上下文中替换经过身份验证的javax.security.Principal？

import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;
import javax.security.auth.Subject;
import javax.security.auth.login.LoginContext;
import javax.security.auth.login.LoginException;
import javax.security.auth.spi.LoginModule;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import java.security.Principal;

public class CustomPrincipal implements Principal {
    private String name;

    public CustomPrincipal(String name) {
        this.name = name;
    }

    @Override
    public String getName() {
        return name;
    }

    // 其他自定义方法和属性...

    public static void replacePrincipal(String username) {
        FacesContext facesContext = FacesContext.getCurrentInstance();
        ExternalContext externalContext = facesContext.getExternalContext();
        HttpServletRequest request = (HttpServletRequest) externalContext.getRequest();
        HttpSession session = request.getSession();

        CustomPrincipal customPrincipal = new CustomPrincipal(username);
        session.setAttribute("javax.security.auth.Principal", customPrincipal);
    }
}