forms - Thymeleaf:点击提交按钮后显示成功消息

Question

我有一个 spring-boot应用程序，与 Thymeleaf .我有非常基本的场景。有一个表单，当用户点击提交按钮时，表单数据应该发送到 Controller ，但是在同一页面中，应该会显示成功消息。

表格非常简单:

<form th:action="@{/suggest-event}"  method="post">
    <button type="submit" class="btn btn-primary">Submit</button>
</form>
<div th:switch="${message}">
    <div th:case="'Success'" class="alert alert-success">
        <strong>Success!</strong> Operation performed successfully.
    </div>
    <div th:case="'Failed'" class="alert alert-danger">
        <strong>Failure!</strong> Operation failed. Please try again 
    </div>
</div>

要加载表单，我在 Controller 中使用了以下方法:

@GetMapping("/suggest-event")
public String suggestEvent(@RequestParam(value = "message", required = false) String message) {

    model.addAttribute("message",message);
    return "/suggested-event/suggestEvent";
}

然后是回答post请求的方法:

@PostMapping("/suggest-event")
public String receiveSuggestedEvent( RedirectAttributes redirectAttributes) {

    redirectAttributes.addAttribute("message", "Success");
    return "redirect:/suggest-event";
}

问题是，成功消息始终存在(第一次加载页面时，以及在我提交表单之前)。我该如何解决？

Answer 1

您可以稍微更改代码:

@GetMapping("/suggest-event")
public String suggestEvent() {
    return "/suggested-event/suggestEvent";
} 

@PostMapping("/suggest-event")
public String receiveSuggestedEvent(BindingResult result, RedirectAttributes redirectAttributes) {
    redirectAttributes.addFlashAttribute("message", "Failed");
    redirectAttributes.addFlashAttribute("alertClass", "alert-danger");
    if (result.hasErrors()) {
        return "redirect:/suggest-event";
    }
    redirectAttributes.addFlashAttribute("message", "Success");
    redirectAttributes.addFlashAttribute("alertClass", "alert-success");
    return "redirect:/suggest-event";
}

我在 html 中显示消息的解决方案:

<div th:if="${message}" th:text="${message}" th:class="${'alert ' + alertClass}"/>

但底线是替换 addFlashAttribute 而不是 addAttribute 并从@GetMapping 中删除消息。