Spring MVC重定向失败

我想用Spring MVC+Mybatis做一个登录页面，控制器如下：

@Controller
public class LoginController {
private final UserService userService;

@Autowired
public LoginController(@Qualifier("userService") UserService userService) {
    this.userService = userService;
}

@RequestMapping(value = "/login")
public ModelAndView Login(String username, String password, 
                          ModelAndView mv, HttpSession session) {
    User user = userService.login(username, password);

    // **This is where problems occured**
    if (user != null) {
        session.setAttribute("user", user);
        mv.setView(new RedirectView("/main"));
    } else {
        mv.addObject("message","Login failed.");
        mv.setViewName("loginForm");
    }
    return mv; // with correct value, but responses 404 error
}

@RequestMapping(value = "/loginForm")
public String LoginForm() {
    return "loginForm";
}

@RequestMapping(value = "/main")
public String Main(Model model) {
    return "main";
}
}

我有两个jsp文件：

/WEB-INF/jsp/loginForm.jsp
/WEB-INF/jsp/main.jsp

无论我是否正确提交登录表单，都会出现404错误：

HTTP Status 404 - /WEB-INF/jsp/login.jsp

在调试模式下运行时，mv返回的“/main”正确，因此我感到困惑

下面的代码可以工作，但我不能再添加错误消息来查看了

@RequestMapping(value = "/login")
public String Login(String username, String password, HttpSession session) {
    User user = userService.login(username, password);
    if (user != null) {
        session.setAttribute("user", user);
        return "redirect:/main";
    } else {
        session.setAttribute("message","Login failed");
        return "redirect:/loginForm";
    }
}

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我也面临同样的问题，但这对我有帮助

ModelAndView model = new ModelAndView();
 if (user != null) {
        session.setAttribute("user", user);
        model = new ModelAndView("/main");
    } else {
        mv.addObject("message","Login failed.");
        model = new ModelAndView("/loginForm");
    }
return model;

---

您使用的是哪种Spring配置，基于XML还是基于Java？已解决，谢谢，原因是一个空参数。我知道这是有效的，我代码中的参数mv是空的