在 thymeleaf 页面的 model object 字段中未显示错误

Question

Thymeleaf 方法fields.errors()用于收集所有验证，未在 html 页面中显示错误，并给出错误我已经尝试了所有方法来捕获错误。 也试过， https://www.thymeleaf.org/doc/tutorials/2.1/thymeleafspring.html#dynamic-fields

主要错误： “ bean 名称‘user’的 BindingResult 和普通目标 object 都不能用作请求属性”

Error >>



Caused by: java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'user' available as request attribute
        at org.springframework.web.servlet.support.BindStatus.<init>(BindStatus.java:153)
        at org.springframework.web.servlet.support.RequestContext.getBindStatus(RequestContext.java:903)
        at org.thymeleaf.spring5.context.webmvc.SpringWebMvcThymeleafRequestContext.getBindStatus(SpringWebMvcThymeleafRequestContext.java:227)
        at org.thymeleaf.spring5.util.FieldUtils.getBindStatusFromParsedExpression(FieldUtils.java:306)
        at org.thymeleaf.spring5.util.FieldUtils.getBindStatus(FieldUtils.java:253)
        at org.thymeleaf.spring5.util.FieldUtils.getBindStatus(FieldUtils.java:227)
        at org.thymeleaf.spring5.processor.AbstractSpringFieldTagProcessor.doProcess(AbstractSpringFieldTagProcessor.java:174)
        at org.thymeleaf.processor.element.AbstractAttributeTagProcessor.doProcess(AbstractAttributeTagProcessor.java:74)
        ... 69 more
    
        Caused by: org.attoparser.ParseException: Error during execution of processor 'org.thymeleaf.spring5.processor.SpringInputGeneralFieldTagProcessor' (template: "user_login" - line 28, col 21)
        at org.attoparser.MarkupParser.parseDocument(MarkupParser.java:393)
        at org.attoparser.MarkupParser.parse(MarkupParser.java:257)
        at org.thymeleaf.templateparser.markup.AbstractMarkupTemplateParser.parse(AbstractMarkupTemplateParser.java:230)
        ... 48 more
    Caused by: org.thymeleaf.exceptions.TemplateProcessingException: Error during execution of processor 'org.thymeleaf.spring5.processor.SpringInputGeneralFieldTagProcessor' (template: "user_login" - line 28, col 21)
 

Controller class

@GetMapping("/user_login")
public String getUserLoginPage(Model model){
    LoginModel user_model  = new LoginModel();
    model.addAttribute("title", "User Login Page");
    model.addAttribute("user", user_model);
    return "user_login";
}

// user login Handler
@PostMapping("/process_user_login")
public String processUserLogin(
    @Valid @ModelAttribute LoginModel user,
    BindingResult bindingResult,Model model){
    
    if(bindingResult.hasErrors()){
        logger.info("user login from has some error");

        return "user_login";
    }
    model.addAttribute("user", user);
    return "user_login";
}

Model class

    package com.attendance.model;

import javax.validation.constraints.NotBlank;
import javax.validation.constraints.Size;

public class LoginModel {

    @NotBlank(message = "email cannot be blank")
    @Size(min = 3, max = 20, message = " 3 -20 charater" )
    private String userEmail;

    @NotBlank(message = "password cannot be blank")
    private String password;

    public LoginModel() {
        super();
    }
    
    public LoginModel(String userEmail, String password) {
        super();
        this.userEmail = userEmail;
        this.password = password;
    }
    public String getUserEmail() {
        return userEmail;
    }
    public void setUserEmail(String userEmail) {
        this.userEmail = userEmail;
    }
    public String getPassword() {
        return password;    
    }
    public void setPassword(String password) {
        this.password = password;
    }
    @Override
    public String toString() {
        return "LoginModel [userEmail=" + userEmail + ", password=" + password + "]";
    }

}



html page /view 


    <!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org" th:replace="base::layout(~{::section})">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <style rel="stylesheet" th:href="@{/css/userlogin.css}" ></style>
   
    <title>Home Page </title>
</head>

<body>
    <section>
        
            <div class="card card-container mb-4 pb-5">
                <!-- <img class="profile-img-card" src="//lh3.googleusercontent.com/-6V8xOA6M7BA/AAAAAAAAAAI/AAAAAAAAAAA/rzlHcD0KYwo/photo.jpg?sz=120" alt="" /> -->
                <img id="profile-img" class="profile-img-card" src="//ssl.gstatic.com/accounts/ui/avatar_2x.png" />
                <p id="profile-name" class="profile-name-card"></p>
                <form th:object="${user}" th:action="@{/process_user_login}" method="post" class="form-signin">
                    <span id="reauth-email" class="reauth-email"></span>

                  

                    <input 
                    type="email"
                    name="userEmail"
                    th:field="*{userEmail}"
                    id="inputEmail" 
                    class="form-control" 
                    placeholder="Email address"
                        autofocus />
                        
                   <p th:if="${#fields.hasErrors('userEmail')}" >Incorrect date</p> 
                  <!--  <p th:each="e : ${#fields.errors('userEmail')}" th:text="${e}" ></p> -->
                        

                    <input 
                    type="password" 
                    name="password"
                   th:field="*{password}"
                    id="inputPassword" 
                    class="form-control" 
                    placeholder="Password" />
                    
                  

                  

                    <div id="remember" class="checkbox">
                        <label>
                            <input type="checkbox" value="remember-me"> Remember me
                        </label>
                    </div>
                    <button class="btn btn-lg btn-primary btn-block btn-signin" type="submit">Sign in</button>
                </form><!-- /form -->
                <a href="#" class="forgot-password">
                    Forgot the password?
                </a>
            </div><!-- /card-container -->
  
    </section>
    
</body>

</html>

Answer 1

在 Thymeleaf 中，您可以使用 th:field 属性将表单字段绑定到 model object 中的字段，并使用 th:errors 属性显示该字段的任何验证错误。

例如，如果您有一个名为 model object 的用户，其字段名为 email，并且您想要显示 email 地址的输入字段和任何验证错误，您可以使用以下代码：

<form>
  <label for="email">Email:</label>
  <input type="text" th:field="*{user.email}" id="email" />
  <div th:if="${#fields.hasErrors('user.email')}" th:errors="*{user.email}">Email error</div>
</form>

如果 email 字段未显示任何验证错误，则可能是该字段未被验证或验证未被触发。 要解决此问题，您可以尝试以下操作：

确保 model object 正确传递到 Thymeleaf 模板，并且该字段绑定到正确的 model object 字段。 确保在服务器端验证该字段，并且正确应用验证规则。 确保正确提交了表单，并且在提交表单时触发了验证。 如果您仍然无法显示 model object 字段的验证错误，查看 th:field 和 th:errors 属性以及 Thymeleaf 验证方言的文档可能会有所帮助，以确保您正在使用它们正确。 您可能还想考虑在服务器端调试验证过程以识别任何问题。