springboot处理表单提交有个错误 #7

@GetMapping("/greeting")
public String greetingForm(Model model) {
    model.addAttribute("greeting", new Greeting());
    return "greeting";
}

@PostMapping("/greeting")
public String greetingSubmit(@ModelAttribute Greeting greeting, Model model) {
    model.addAttribute("greeting", greeting);
    return "result";
}