I try to pass data html to controller but i have a error like that. My GET method is work clearly but POST method doesn't work

```
java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'post' available as request attribute
    at org.springframework.web.servlet.support.BindStatus.<init>(BindStatus.java:144) ~[spring-webmvc-4.3.4.RELEASE.jar:4.3.4.RELEASE]
    at org.thymeleaf.spring4.util.FieldUtils.getBindStatusFromParsedExpression(FieldUtils.java:401) ~[thymeleaf-spring4-2.1.5.RELEASE.jar:2.1.5.RELEASE]
    at org.thymeleaf.spring4.util.FieldUtils.getBindStatus(FieldUtils.java:328) ~[thymeleaf-spring4-2.1.5.RELEASE.jar:2.1.5.RELEASE]
    at org.thymeleaf.spring4.util.FieldUtils.getBindStatus(FieldUtils.java:294) ~[thymeleaf-spring4-2.1.5.RELEASE.jar:2.1.5.RELEASE]
    at org.thymeleaf.spring4.processor.attr.AbstractSpringFieldAttrProcessor.processAttribute(AbstractSpringFieldAttrProcessor.java:98) ~[thymeleaf-spring4-2.1.5.RELEASE.jar:2.1.5.RELEASE]
    at org.thymeleaf.processor.attr.AbstractAttrProcessor.doProcess(AbstractAttrProcessor.java:87) ~[thymeleaf-2.1.5.RELEASE.jar:2.1.5.RELEASE]
    at org.thymeleaf.processor.AbstractProcessor.process(AbstractProcessor.java:212) ~[thymeleaf-2.1.5.RELEASE.jar:2.1.5.RELEASE]
    at org.thymeleaf.dom.Node.applyNextProcessor(Node.java:1017) ~[thymeleaf-2.1.5.RELEASE.jar:2.1.5.RELEASE]
    at org.thymeleaf.dom.Node.processNode(Node.java:972) ~[thymeleaf-2.1.5.RELEASE.jar:2.1.5.RELEASE]
    at org.thymeleaf.dom.NestableNode.computeNextChild(NestableNode.java:695) ~[thymeleaf-2.1.5.RELEASE.jar:2.1.5.RELEASE]
    at org.thymeleaf.dom.NestableNode.doAdditionalProcess(NestableNode.java:668) ~[thymeleaf-2.1.5.RELEASE.jar:2.1.5.RELEASE]
    at org.thymeleaf.dom.Node.processNode(Node.java:990) ~[thymeleaf-2.1.5.RELEASE.jar:2.1.5.RELEASE]

```

and this is my html form 

```
 <form autocomplete="off" action="#" th:action="@{/(${titleId})}"
              th:object="${post}" method="post" class="form-horizontal"
              role="form">
            <h2>Formu doldur aramıza katıl..</h2>
            <div class="form-group">
                <div class="col-sm-9">
                    <input type="text" th:field="*{postBody}" placeholder="yorumla"
                           class="form-control" />
                </div>
            </div>

            <div class="form-group">
                <div class="col-sm-9">
                    <button type="submit" class="btn btn-primary btn-block">Kayıt Ol</button>
                </div>
            </div>
        </form>

```

finally my controller method is here

```
@RequestMapping(value = "/{id}", method = RequestMethod.POST)
    public ModelAndView savePost(@Valid Post post,@PathVariable("id")Long id){

        ModelAndView modelAndView =new ModelAndView();

        Title title = titleService.getTitleById(id);

        Authentication auth = SecurityContextHolder.getContext().getAuthentication();
        User user = userService.findUserByEmail(auth.getName());

        Date date = new Date();

        Post post1 = new Post();

        post1.setPostBody(post.getPostBody());
        post1.setPostDate(date);
        post1.setPostSender(user);
        post1.setPostTitle(title);

        postService.savePost(post1);
        modelAndView.addObject("post",post1);
        modelAndView.setViewName("homePage2");

        return modelAndView;
    }

```

i can't understand why i have an error.