Thymeleaf不返回错误消息字段，但进入错误页面

Question

我是Spring Boot的新手，我正在尝试通过编写网站来学习。我已经在网络上进行了一次休眠验证，当我正确填写每个字段时，一切都会顺利进行，但是例如，当我将任何字段留空时，Thymeleaf就会给我一个错误页面，并且不会在我的HTML页面上显示错误字段

这是我的代码：

POM.xml：

http://maven.apache.org/xsd/maven-4.0.0.xsd"> 4.0.0 org.springframework.boot spring-boot-starter-parent 2.1.3.RELEASE

<groupId>dentistry</groupId>
<artifactId>Dentistry</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>Dentistry</name>
<description>Demo project for Spring Boot</description>


<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>

    <dependency>
        <groupId>org.thymeleaf</groupId>
        <artifactId>thymeleaf</artifactId>
        <version>3.0.11.RELEASE</version>
    </dependency>

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
    </dependency>

    <dependency>
        <groupId>org.webjars</groupId>
        <artifactId>bootstrap</artifactId>
        <version>4.3.1</version>
    </dependency>

    <dependency>
        <groupId>org.webjars.bower</groupId>
        <artifactId>jquery</artifactId>
        <version>3.3.1</version>
    </dependency>

    <dependency>
        <groupId>org.webjars</groupId>
        <artifactId>webjars-locator</artifactId>
        <version>0.36</version>
    </dependency>


    <dependency>
        <groupId>org.hibernate.validator</groupId>
        <artifactId>hibernate-validator</artifactId>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.springframework.security/spring-security-core -->
    <dependency>
        <groupId>org.springframework.security</groupId>
        <artifactId>spring-security-core</artifactId>
        <!-- <version>5.1.5.RELEASE</version> -->
    </dependency>


    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <!-- <version>1.3.0.RELEASE</version> -->
    </dependency>

</dependencies>

<properties>
    <java.version>1.8</java.version>
</properties>

实体类：

package dentistry.model;

import javax.persistence.Column; 
import javax.persistence.Entity; 
import javax.persistence.GeneratedValue; 
import javax.persistence.GenerationType; 
import javax.persistence.Id; 
import javax.validation.constraints.NotEmpty; 
import javax.validation.constraints.Size;

@Entity public class User {

@Id
@NotEmpty
@Column(unique=true)
private String id;
@NotEmpty
private String name;
@NotEmpty
@Size(min=3)
private String pass;
private String role;

public User() {}

public User(String id, String name, String pass, String role) {
    super();
    this.id = id;
    this.name = name;
    this.pass = pass;
    this.role = role;
}

public String getId() {
    return id;
}
public void setId(String id) {
    this.id = id;
}
public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}
public String getPass() {
    return pass;
}
public void setPass(String pass) {
    this.pass = pass;
}
public String getRole() {
    return role;
}
public void setRole(String role) {
    this.role = role;
}
}

控制器：

package dentistry.controllers;

import javax.validation.Valid;

import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.validation.BindingResult; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PostMapping; import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

import dentistry.login.LoginService; import dentistry.model.User;

@Controller public class RegisterController implements WebMvcConfigurer{

@Autowired
LoginService loginService;

@GetMapping("/register")
public String registerForm(Model model) {

    model.addAttribute("new_user", new User());
    return "newUser";
}

@PostMapping("/register")
public String registerUser(@Valid User user, BindingResult bindingResult, Model model) {

    if(bindingResult.hasErrors()) {return "newUser";}

    if(loginService.isUserPresent(user.getId())){
        model.addAttribute("exist", true);
        return "newUser";
    }

    loginService.addUser(user);
    return "intro";
}
}

HTML：

 <!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<link rel="stylesheet" href="../../static/css/flatly/bootstrap.min.css"
    th:href="@{css/style.css}" />

<link rel="stylesheet" type="text/css" media="all"
    href="../../static/css/flatly/bootstrap.min.css"
    th:href="@{/css/flatly/bootstrap.min.css}" />
<script th:src="@{webjars/jquery/jquery.min.js}"></script>
<script th:src="@{webjars/bootstrap/bootstrap.min.js}"></script>
<title>Register</title>
</head>
<body>
    <div th:replace="header::header"></div>

    <div layout:fragment="content" class="container myspace">
    <div class="alert alert-info" th:if="${exist}">
    <p class="text text-center">
    Ky perdorues eshte regjistruar me pare!
    </p>
    </div>
        <div class="jumbotron">
            <h2>Register</h2>
            <br>
            <form action="#" th:action="@{/register}" th:object="${new_user}" method="post">

                <div class="form-group">
                    <label for="id">ID</label> <input type="text" th:field="*{id}"
                        id="id" class="form-control" />
                        <div class="text text-danger" th:if="${#fields.hasErrors('id')}" th:errors="*{id}">Id errorr</div>
                </div>

                <div class="form-group">
                    <label for="name">Name</label> <input type="text"
                        th:field="*{name}" id="name" class="form-control" />
                        <div class="text text-danger" th:if="${#fields.hasErrors('name')}" th:errors="*{name}">Name error</div>
                </div>

                <div class="form-group">
                    <label for="pass">Pass</label> <input type="password"
                        th:field="*{pass}" id="pass" class="form-control" />
                        <div class="text text-danger" th:if="${#fields.hasErrors('pass')}" th:errors="*{password}">Pass error</div>
                </div>
                <div class="form-group">
                    <label for="role">Role</label> <input type="text"
                        th:field="*{role}" id="role" class="form-control" />
                        <div class="text text-danger" th:if="${#fields.hasErrors('role')}" th:errors="*{role}">Role error</div>
                </div>
                <input type="submit" value="Submit" class="btn-primary">
            </form>
        </div>
    </div>

    <div th:replace="footer::footer"></div>
</body>
</html>

主班：

package dentistry;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DentistryApplication {

    public static void main(String[] args) {
        SpringApplication.run(DentistryApplication.class, args);
    }

}

错误：

Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback.

Sat Apr 13 21:26:12 CEST 2019
There was an unexpected error (type=Internal Server Error, status=500).
An error happened during template parsing (template: "class path resource [templates/newUser.html]")
org.thymeleaf.exceptions.TemplateInputException: An error happened during template parsing (template: "class path resource [templates/newUser.html]")
    at org.thymeleaf.templateparser.markup.AbstractMarkupTemplateParser.parse(AbstractMarkupTemplateParser.java:241)
    at org.thymeleaf.templateparser.markup.AbstractMarkupTemplateParser.parseStandalone(AbstractMarkupTemplateParser.java:100)
    at org.thymeleaf.engine.TemplateManager.parseAndProcess(TemplateManager.java:666)
    at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1098)
    at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1072)
    at org.thymeleaf.spring5.view.ThymeleafView.renderFragment(ThymeleafView.java:362)
    at org.thymeleaf.spring5.view.ThymeleafView.render(ThymeleafView.java:189)
    at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1370)
    at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1116)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1055)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:908)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:660)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.servlet.resource.ResourceUrlEncodingFilter.doFilter(ResourceUrlEncodingFilter.java:63)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:200)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:834)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1415)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: org.attoparser.ParseException: Error during execution of processor 'org.thymeleaf.spring5.processor.SpringInputGeneralFieldTagProcessor' (template: "newUser" - line 29, col 52)
    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)
    ... 55 more
Caused by: org.thymeleaf.exceptions.TemplateProcessingException: Error during execution of processor 'org.thymeleaf.spring5.processor.SpringInputGeneralFieldTagProcessor' (template: "newUser" - line 29, col 52)
    at org.thymeleaf.processor.element.AbstractAttributeTagProcessor.doProcess(AbstractAttributeTagProcessor.java:117)
    at org.thymeleaf.processor.element.AbstractElementTagProcessor.process(AbstractElementTagProcessor.java:95)
    at org.thymeleaf.util.ProcessorConfigurationUtils$ElementTagProcessorWrapper.process(ProcessorConfigurationUtils.java:633)
    at org.thymeleaf.engine.ProcessorTemplateHandler.handleStandaloneElement(ProcessorTemplateHandler.java:918)
    at org.thymeleaf.engine.TemplateHandlerAdapterMarkupHandler.handleStandaloneElementEnd(TemplateHandlerAdapterMarkupHandler.java:260)
    at org.thymeleaf.templateparser.markup.InlinedOutputExpressionMarkupHandler$InlineMarkupAdapterPreProcessorHandler.handleStandaloneElementEnd(InlinedOutputExpressionMarkupHandler.java:256)
    at org.thymeleaf.standard.inline.OutputExpressionInlinePreProcessorHandler.handleStandaloneElementEnd(OutputExpressionInlinePreProcessorHandler.java:169)
    at org.thymeleaf.templateparser.markup.InlinedOutputExpressionMarkupHandler.handleStandaloneElementEnd(InlinedOutputExpressionMarkupHandler.java:104)
    at org.attoparser.HtmlElement.handleStandaloneElementEnd(HtmlElement.java:79)
    at org.attoparser.HtmlMarkupHandler.handleStandaloneElementEnd(HtmlMarkupHandler.java:241)
    at org.attoparser.MarkupEventProcessorHandler.handleStandaloneElementEnd(MarkupEventProcessorHandler.java:327)
    at org.attoparser.ParsingElementMarkupUtil.parseStandaloneElement(ParsingElementMarkupUtil.java:96)
    at org.attoparser.MarkupParser.parseBuffer(MarkupParser.java:706)
    at org.attoparser.MarkupParser.parseDocument(MarkupParser.java:301)
    ... 57 more
Caused by: java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'new_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)
    ... 70 more

Answer 1

我有答案，而不是我写了model.addAttribute("new_user", new User());而不是model.addAttribute("user", new User()); 因此，将new_user替换为user，它将起作用