如何使用 Thymeleaf 将对象的 ID 添加到表单的隐藏输入中答案

【问题标题】：How to add the ID of an object to a hidden input of a form with Thymeleaf如何使用 Thymeleaf 将对象的 ID 添加到表单的隐藏输入中
【发布时间】：2018-11-09 15:01:22
【问题描述】：

我正在使用 th:each 将餐厅列表到 HTML 表中。我想在可以删除实际行数据的每一行中添加一个按钮（所以我想将餐厅 ID 发送到 Spring，然后我想从数据库中删除该餐厅。在每一行中我也想创建一个添加管理表单（因为我不想为此仅使用 1 个输入字段创建新的 HTML 页面）。所以基本上我的问题是，我该怎么做？

这是我的 HTML 表格：

<table class="table">
                    <thead>
                    <tr>
                        <th scope="col">Restaurant</th>
                        <th scope="col">Delivery time</th>
                        <th scope="col">Delivery Price</th>
                        <th scope="col">Minimum Order Price</th>
                        <th scope="col">Shopping Hours</th>
                    </tr>
                    </thead>
                    <tbody>
                        <tr th:each="rest: ${restaurants}">

                            <td th:text="${rest.name}"/>
                            <td th:text="${rest.avgdeliverytime}"/>
                            <td th:text="${rest.deliveryprice}"/>
                            <td th:text="${rest.minorderprice}"/>
                            <td th:text="${rest.hours.open} + ' - '+ ${rest.hours.close}"/>
                            <td>

                                <form th:action="@{'restaurants/delete'}" method="post">
                                    <button type="submit" class="btn btn-danger btn-block"/>
                                    Delete</button>
                                </form>

                            </td>
                            <td>
                                <form th:action="@{'restaurants/newadmin'}" th:object="${restadmin}" method="post">
                                <input type="hidden" name="restaurantId" th:value="${rest.id}" th:field="${restadmin.restid}">
                                <input type="email" class="form-control" id="adminEmail" th:field="${restadmin.email}">
                                <button type="submit" class="btn btn-secondary btn-block"/>
                                Add Admin</button>
                                </form>

                            </td>
                        </tr>
                    </tbody>
                </table>

为此，我创建了一个名为 RestaurantAdmin 的新类，用于将此对象发送回控制器

public class RestaurantAdmin {

private String email;
private Long restid;

public RestaurantAdmin() {
}

public RestaurantAdmin(String email, Long restid) {
    this.email = email;
    this.restid = restid;
}

public String getEmail() {
    return email;
}

public void setEmail(String email) {
    this.email = email;
}

public Long getRestid() {
    return restid;
}

public void setRestid(Long restid) {
    this.restid = restid;
}

我的控制器方法：

    @GetMapping("/restaurants")
public String getAllRestaurants(Model model) {
    model.addAttribute("restaurants", restaurantService.findAll());
    model.addAttribute("restadmin", new RestaurantAdmin());
    return "administration/restaurants";
}
  @PostMapping("/restaurants/newadmin")
public ModelAndView addNewAdminToRestaurant(@ModelAttribute(value="restadmin") RestaurantAdmin restaurantAdmin,
                                            final BindingResult result, ModelAndView modelAndView) {

    if(result.hasErrors()) {
        modelAndView.addObject("error", "Some error are occured!");
        modelAndView.setViewName("administration/restaurants");
        return modelAndView;
    }

    System.out.println(restaurantAdmin.getRestid());
    System.out.println(restaurantAdmin.getEmail());

    modelAndView.setViewName("administration/restaurants");
    return modelAndView;
}

使用这些代码，我没有遇到任何异常，但是当我将电子邮件地址添加到添加管理表单然后将其发布到 Spring 时，restaurantAdmin 的 ID 为空。

如果我在删除表单中添加以下行（这实际上没有任何意义，因为我什至没有要发布的对象或其他东西。）

<input type="hidden" name="restaurantId" th:field="${rest.id}">

我得到了这个例外：

2018-11-09 15:44:16.504 ERROR 17052 --- [nio-8443-exec-3] org.thymeleaf.TemplateEngine             : [THYMELEAF][https-jsse-nio-8443-exec-3] Exception processing template "administration/restaurants": An error happened during template parsing (template: "class path resource [templates/administration/restaurants.html]")

org.thymeleaf.exceptions.TemplateInputException: An error happened during template parsing (template: "class path resource [templates/administration/restaurants.html]")
at org.thymeleaf.templateparser.markup.AbstractMarkupTemplateParser.parse(AbstractMarkupTemplateParser.java:241) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.templateparser.markup.AbstractMarkupTemplateParser.parseStandalone(AbstractMarkupTemplateParser.java:100) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.engine.TemplateManager.parseAndProcess(TemplateManager.java:666) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1098) [thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1072) [thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.spring5.view.ThymeleafView.renderFragment(ThymeleafView.java:354) [thymeleaf-spring5-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.spring5.view.ThymeleafView.render(ThymeleafView.java:187) [thymeleaf-spring5-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1325) [spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1069) [spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1008) [spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) [spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974) [spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:866) [spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851) [spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) [tomcat-embed-websocket-8.5.34.jar:8.5.34]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:320) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:127) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:91) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:119) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:137) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:170) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:200) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:116) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.csrf.CsrfFilter.doFilterInternal(CsrfFilter.java:100) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:66) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:215) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:178) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:357) [spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:270) [spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) [spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) [spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) [spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) [spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.34.jar:8.5.34]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1135) [na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) [na:na]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.34.jar:8.5.34]
at java.base/java.lang.Thread.run(Thread.java:844) [na:na]
Caused by: org.attoparser.ParseException: Error during execution of processor 'org.thymeleaf.spring5.processor.SpringInputGeneralFieldTagProcessor' (template: "administration/restaurants" - line 54, col 82)
at org.attoparser.MarkupParser.parseDocument(MarkupParser.java:393) ~[attoparser-2.0.4.RELEASE.jar:2.0.4.RELEASE]
at org.attoparser.MarkupParser.parse(MarkupParser.java:257) ~[attoparser-2.0.4.RELEASE.jar:2.0.4.RELEASE]
at org.thymeleaf.templateparser.markup.AbstractMarkupTemplateParser.parse(AbstractMarkupTemplateParser.java:230) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
... 87 common frames omitted

Caused by: org.thymeleaf.exceptions.TemplateProcessingException: Error during execution of processor 'org.thymeleaf.spring5.processor.SpringInputGeneralFieldTagProcessor' (template: "administration/restaurants" - line 54, col 82)
at org.thymeleaf.processor.element.AbstractAttributeTagProcessor.doProcess(AbstractAttributeTagProcessor.java:117) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.processor.element.AbstractElementTagProcessor.process(AbstractElementTagProcessor.java:95) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.util.ProcessorConfigurationUtils$ElementTagProcessorWrapper.process(ProcessorConfigurationUtils.java:633) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.engine.ProcessorTemplateHandler.handleStandaloneElement(ProcessorTemplateHandler.java:918) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.engine.StandaloneElementTag.beHandled(StandaloneElementTag.java:228) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.engine.Model.process(Model.java:282) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.engine.Model.process(Model.java:290) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.engine.IteratedGatheringModelProcessable.processIterationModel(IteratedGatheringModelProcessable.java:367) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.engine.IteratedGatheringModelProcessable.process(IteratedGatheringModelProcessable.java:221) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.engine.ProcessorTemplateHandler.handleCloseElement(ProcessorTemplateHandler.java:1640) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.engine.TemplateHandlerAdapterMarkupHandler.handleCloseElementEnd(TemplateHandlerAdapterMarkupHandler.java:388) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.templateparser.markup.InlinedOutputExpressionMarkupHandler$InlineMarkupAdapterPreProcessorHandler.handleCloseElementEnd(InlinedOutputExpressionMarkupHandler.java:322) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.standard.inline.OutputExpressionInlinePreProcessorHandler.handleCloseElementEnd(OutputExpressionInlinePreProcessorHandler.java:220) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.templateparser.markup.InlinedOutputExpressionMarkupHandler.handleCloseElementEnd(InlinedOutputExpressionMarkupHandler.java:164) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.attoparser.HtmlElement.handleCloseElementEnd(HtmlElement.java:169) ~[attoparser-2.0.4.RELEASE.jar:2.0.4.RELEASE]
at org.attoparser.HtmlMarkupHandler.handleCloseElementEnd(HtmlMarkupHandler.java:412) ~[attoparser-2.0.4.RELEASE.jar:2.0.4.RELEASE]
at org.attoparser.MarkupEventProcessorHandler.handleCloseElementEnd(MarkupEventProcessorHandler.java:473) ~[attoparser-2.0.4.RELEASE.jar:2.0.4.RELEASE]
at org.attoparser.ParsingElementMarkupUtil.parseCloseElement(ParsingElementMarkupUtil.java:201) ~[attoparser-2.0.4.RELEASE.jar:2.0.4.RELEASE]
at org.attoparser.MarkupParser.parseBuffer(MarkupParser.java:725) ~[attoparser-2.0.4.RELEASE.jar:2.0.4.RELEASE]
at org.attoparser.MarkupParser.parseDocument(MarkupParser.java:301) ~[attoparser-2.0.4.RELEASE.jar:2.0.4.RELEASE]
... 89 common frames omitted

Caused by: java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'rest' available as request attribute
at org.springframework.web.servlet.support.BindStatus.<init>(BindStatus.java:153) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.servlet.support.RequestContext.getBindStatus(RequestContext.java:903) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.thymeleaf.spring5.context.webmvc.SpringWebMvcThymeleafRequestContext.getBindStatus(SpringWebMvcThymeleafRequestContext.java:227) ~[thymeleaf-spring5-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.spring5.util.FieldUtils.getBindStatusFromParsedExpression(FieldUtils.java:305) ~[thymeleaf-spring5-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.spring5.util.FieldUtils.getBindStatus(FieldUtils.java:257) ~[thymeleaf-spring5-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.spring5.util.FieldUtils.getBindStatus(FieldUtils.java:226) ~[thymeleaf-spring5-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.spring5.processor.AbstractSpringFieldTagProcessor.doProcess(AbstractSpringFieldTagProcessor.java:174) ~[thymeleaf-spring5-3.0.9.RELEASE.jar:3.0.9.RELEASE]
at org.thymeleaf.processor.element.AbstractAttributeTagProcessor.doProcess(AbstractAttributeTagProcessor.java:74) ~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE]
... 108 common frames omitted

编辑：餐厅实体

@Entity
public class Restaurant {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
@Column(name="RESTAURANT_NAME")
private String name;
@Column(name="AVERAGE_DELIVERY_TIME")
private String avgdeliverytime;
@Column(name="MINIMUM_ORDER_PRICE")
private Short minorderprice;
@Column(name="DELIVERY_PRICE")
private Short deliveryprice;

@Embedded
private ShoppingHours hours;

@ElementCollection
@CollectionTable(name = "MENU", joinColumns = @JoinColumn(name = "RESTAURANT_ID"))
@Column(name = "MENU")
private List<Meal> menu;

@OneToMany
@JoinTable(name = "RESTAURANT_WORKERS",
        joinColumns = {@JoinColumn(name = "RESTAURANT_ID")},
        inverseJoinColumns = {@JoinColumn(name = "WORKER_ID")})
@Column(name = "WORKER_ID")
private List<User> workers;


public Restaurant() {
}

public Restaurant(String name, String avgdeliverytime, Short minorderprice, Short deliveryprice,
                  ShoppingHours hours) {
    this.name = name;
    this.avgdeliverytime = avgdeliverytime;
    this.minorderprice = minorderprice;
    this.deliveryprice = deliveryprice;
    this.hours = hours;
}

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 String getAvgdeliverytime() {
    return avgdeliverytime;
}

public void setAvgdeliverytime(String avgdeliverytime) {
    this.avgdeliverytime = avgdeliverytime;
}

public Short getMinorderprice() {
    return minorderprice;
}

public void setMinorderprice(Short minorderprice) {
    this.minorderprice = minorderprice;
}

public Short getDeliveryprice() {
    return deliveryprice;
}

public void setDeliveryprice(Short deliveryprice) {
    this.deliveryprice = deliveryprice;
}

public ShoppingHours getHours() {
    return hours;
}

public void setHours(ShoppingHours hours) {
    this.hours = hours;
}

public List<Meal> getMenu() {
    return menu;
}

public void setMenu(List<Meal> menu) {
    this.menu = menu;
}

}

【问题讨论】：

标签： java spring spring-mvc thymeleaf

【解决方案1】：

您不能将th:value 和th:field 添加在一起，因为th:field 会覆盖它。您可以做的是删除 th:field 标记，而是使用名称和值。因此，您将收到两个@RequestParam，而不是收到@ModelAttribute。为此，您需要在代码中添加以下更改。

控制器

@PostMapping("/restaurants/newadmin")
public ModelAndView addNewAdminToRestaurant(ModelAndView modelAndView,
           @RequestParam("restaurantId") Long id,
           @RequestParam("email") String email) { ... }

HTML

<form th:action="@{'restaurants/newadmin'}" method="post">
    <input type="hidden" name="restaurantId" th:value="${rest.id}">
    <input type="email" name="email" class="form-control" id="adminEmail">
    <button type="submit" class="btn btn-secondary btn-block"/>Add Admin</button>
</form>

提示

当th:object 与多个表单一起使用时，不要只发送一个RestaurantAdmin 对象，而应该尝试为每次迭代创建一个新对象。一个简单的方法是在你的控制器中添加一个@MadelAttribute，每次你在th:object中调用它时都会返回一个新对象。当然，对于您的情况，这不会改变任何事情，因为真正的解决方案是接收两个参数而不是一个对象，但这只是一个小提示。

// In order to use th:object in multiple forms, we must be able to map a new entity to that form.
@ModelAttribute(value = "newRestAdmin")
public RestaurantAdmin newRestAdmin() {return new RestaurantAdmin();}

然后在您的表单上，您只需获取具有给定值的新实体。

<form th:action="@{'restaurants/newadmin'}" th:object="${newRestAdmin}" method="post">

【讨论】：

不幸的是，这不起作用。：/（或者带有rest.id）我想以某种方式将rest.id字段分配给restadmin.restid字段，然后使用“restadmin”模型属性发布RestaurantAdmin对象。（我在问题中添加了 Restaurant 实体）我根本不应该创建那个 RestaurantAdmin 类并在表单标签中定义 th:object 吗？在这种情况下，我应该如何 POST 以将 rest.id 和 email 字段一起后端，然后我应该如何在控制器中接收这些数据？
很高兴我能帮上忙！如果你不介意也投票给我的答案，那就太棒了！那些额外的 10 分确实派上用场:)。
感谢您的详细回答和提示，它现在正在工作:) 如果可以的话，我会投票赞成。：/ 我还没有足够的声誉来做到这一点：D跨度>