春季| 休眠| Thymeleaf：BeanResult'id'的BindingResult或普通目标对象都不能用作请求属性

罗伯特·瓦伦西亚

我正在创建一个用于向数据库添加新角色实体的表单，并且遇到以下错误：

Neither BindingResult nor plain target object for bean name 'id' available as request attribute

我已经在StackOverflow上针对相同错误尝试了几种解决方案，但没有一个起作用。下面显示的是我的角色模型和控制器类，以及它们相关的模板：

角色.java

@Entity
public class Role {
  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Long id;

  @NotNull
  private String name;

  @OneToMany(mappedBy = "role")
  private List<Collaborator> collaborators = new ArrayList<>();

  @ManyToMany(mappedBy = "roles")
  private List<Project> projects = new ArrayList<>();

  public Role() {
  }

  public Long getId() {
    return id;
  }

  public void setId(Long id) {
    this.id = id;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }

  public List<Collaborator> getCollaborators() {
    return collaborators;
  }

  public void setCollaborators(List<Collaborator> collaborators) {
    this.collaborators = collaborators;
  }

  public List<Project> getProjects() {
    return projects;
  }

  public void setProjects(List<Project> projects) {
    this.projects = projects;
  }
}

RoleController.java

@Controller
public class RoleController {
  @Autowired
  private RoleService roleService;

  @GetMapping("/roles")
  public String listRoles(Model model) {
    List<Role> roles = roleService.findAll();
    model.addAttribute("roles", roles);
    return "role/roles";
  }

  @PostMapping("/roles")
  public String addCategory(@Valid Role role, BindingResult result, RedirectAttributes redirectAttributes) {
    if(result.hasErrors()) {
      redirectAttributes.addFlashAttribute("org.springframework.validation.BindingResult.category", result);
      redirectAttributes.addFlashAttribute("role", role);
      return "redirect:/roles";
    }
    roleService.save(role);
    redirectAttributes.addFlashAttribute("flash", new FlashMessage("Role successfully added!", FlashMessage.Status.SUCCESS));
    return "redirect:/roles";
  }
}

role.html

<!DOCTYPE html>
<html>
    <head th:replace="layout :: head('roles')"></head>
    <body>
        <header th:replace="layout :: header"></header>
        <nav th:replace="layout :: nav"></nav>
        <div th:replace="layout :: flash"></div>
        <section>
            <div class="container wrapper">
                <form>
                    <h2>Manage Roles</h2>
                    <div>
                        <ul class="checkbox-list">
                            <li th:each="role : ${roles}"><span class="primary" th:text="${role.name}">Role Name</span></li>
                        </ul>
                    </div>
                    <form th:object="${role}" th:action="@{/roles}" method="post" class="actions add-new-role">
                        <input type="hidden" th:field="*{id}"/>
                        <input type="text" th:field="*{name}" placeholder="Role Name"/>
                        <input type="submit" value="Submit" class="button"/>
                    </form>
                </form>
            </div>
        </section>
    </body>
</html>

堆栈跟踪：

java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'id' available as request attribute
    at org.springframework.web.servlet.support.BindStatus.<init>(BindStatus.java:144) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
    at org.thymeleaf.spring4.util.FieldUtils.getBindStatusFromParsedExpression(FieldUtils.java:401) ~[thymeleaf-spring4-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.spring4.util.FieldUtils.getBindStatus(FieldUtils.java:328) ~[thymeleaf-spring4-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.spring4.util.FieldUtils.getBindStatus(FieldUtils.java:294) ~[thymeleaf-spring4-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.spring4.processor.attr.AbstractSpringFieldAttrProcessor.processAttribute(AbstractSpringFieldAttrProcessor.java:98) ~[thymeleaf-spring4-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.processor.attr.AbstractAttrProcessor.doProcess(AbstractAttrProcessor.java:87) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.processor.AbstractProcessor.process(AbstractProcessor.java:212) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.Node.applyNextProcessor(Node.java:1017) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.Node.processNode(Node.java:972) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.Node.processNode(Node.java:990) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.Node.processNode(Node.java:990) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.Node.processNode(Node.java:990) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.Node.processNode(Node.java:990) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.Node.processNode(Node.java:990) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.Node.processNode(Node.java:990) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.dom.Document.process(Document.java:93) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1155) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1060) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1011) ~[thymeleaf-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.spring4.view.ThymeleafView.renderFragment(ThymeleafView.java:335) ~[thymeleaf-spring4-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.thymeleaf.spring4.view.ThymeleafView.render(ThymeleafView.java:190) ~[thymeleaf-spring4-2.1.6.RELEASE.jar:2.1.6.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1286) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1041) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:984) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.23.jar:8.5.23]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:108) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478) [tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803) [tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459) [tomcat-embed-core-8.5.23.jar:8.5.23]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.23.jar:8.5.23]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_131]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_131]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.23.jar:8.5.23]
    at java.lang.Thread.run(Thread.java:748) [na:1.8.0_131]

编辑：感谢您帮助解决问题。

罗伯特·瓦伦西亚

我最终有了两个模板，一个角色索引和一个用于添加新角色的表单。我也有三种控制器方法：2种get方法（1种用于索引，1种用于表单），以及1种post方法（用于添加新角色）。

RoleController.java

@Controller
public class RoleController {
  @Autowired
  private RoleService roleService;

  // Index of roles
  @GetMapping("/roles")
  public String getRoles(Model model) {
    List<Role> roles = roleService.findAll();
    model.addAttribute("roles", roles);
    return "role/index";
  }

  // New role form
  @GetMapping("/roles/add")
  public String newRoleForm(Model model) {
    if(!model.containsAttribute("role")) {
      model.addAttribute("role", new Role());
    }
    model.addAttribute("action","/roles");
    model.addAttribute("heading","New Role");
    model.addAttribute("submit","Add");
    return "role/form";
  }

  // Add new role
  @PostMapping(value = "/roles")
  public String addNewRole(@Valid Role role, BindingResult result, RedirectAttributes redirectAttributes) {
    if(result.hasErrors()) {
      redirectAttributes.addFlashAttribute("org.springframework.validation.BindingResult.category",result);
      redirectAttributes.addFlashAttribute("role", role);
      return "redirect:/roles/add";
    }
    roleService.save(role);
    redirectAttributes.addFlashAttribute("flash", new FlashMessage("Role successfully added!", FlashMessage.Status.SUCCESS));
    return "redirect:/roles";
  }
}

角色/index.html

<!DOCTYPE html>
<html>
    <head th:replace="layout :: head('roles')"></head>
    <body>
        <header th:replace="layout :: header('Role', '/roles/add')"></header>
        <div th:replace="layout :: flash"></div>
        <nav th:replace="layout :: nav"></nav>

        <section>
            <div class="container wrapper">
                <form>
                    <h2>Manage Roles</h2>
                    <div>
                        <ul class="checkbox-list">
                            <li th:each="role : ${roles}"><span class="primary" th:text="${role.name}">Role Name</span></li>
                        </ul>
                    </div>
                    <br>
                </form>
            </div>
        </section>

        <div th:replace="layout :: scripts"></div>
    </body>
</html>

角色/ form.html

<!DOCTYPE html>
<html>
<head th:replace="layout :: head('roles')"></head>
<body>
    <header>
        <div class="container">
            <div class="site-header">
                <a class="logo" th:href="@{/}">InstaTeam</a>
            </div>
        </div>
    </header>
    <div th:replace="layout :: flash"></div>
    <nav th:replace="layout :: nav"></nav>

    <section>
        <div class="container wrapper">
            <form th:action="@{${action}}" method="post" th:object="${role}">
                <h2 th:text="${heading}">New Role</h2>
                <input type="hidden" th:field="*{id}"/>
                <div class="actions add-new-role">
                    <input type="text" th:field="*{name}" placeholder="Role Name"/>
                    <button th:text="${submit}" type="submit" class="button">Add</button>
                </div>
            </form>
        </div>
    </section>

    <div th:replace="layout :: scripts"></div>
</body>
</html>

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