我在注册表中的用户字段出现错误

Question

Java . lang . illegalstateexception:在org . spring framework . web . servlet . support . bind status .(bind status . Java:153)～[spring-web MVC-5 . 3 . 13 . jar:5 . 3 . 13]在org . spring framework . web . servlet . support . request context . getbindstatus(request context . Java:903)～[spring-web MVC-5 . 3 . 13 . jar:5.3

HTML语言

    <form action="#" th:action="@{/process_register}" th:object="${user}" method="post">
    
                    <h4 class="mb-4 pb-3">Sign Up</h4>
                    <div class="form-group">Username
                        <input type="text" th:field="*{username}" class="form-style">
                    </div>  
                    <div class="form-group mt-2">Password
                        <input type="password" th:field="*{password}"  class="form-style">
                    </div>
...</form>

控制器:

    @GetMapping("/register")
    public String showRegistrationForm(Model model) {
        model.addAttribute("user", new User());

        return "signup_form";
    }



@PostMapping("/process_register")
public String processRegister(Model theModel, User user) {
    
    BCryptPasswordEncoder passwordEncoder = new BCryptPasswordEncoder();
    String encodedPassword = passwordEncoder.encode(user.getPassword());
    
    user.setPassword(encodedPassword);
    userService.save(user);
    return "Wellcome";
}

Answer 1

很可能您忘记在控制器方法中将用户对象添加到模型，这使您进入此表单页面。为了确保这种情况不会最好地发生，只需将模型归因方法添加到始终负责此问题的控制器：

@ModelAttribute("user") 
public User user() { 
  return new User(); 
}

另外，请确保用户类有getters、setters，没有定义arg构造函数——这对百里香很重要