How to handle variable from Spring controller using javascript?

Question

Guys i have problem to get data from variable after execute rest in my controller. Here is sample to show my problem.

Controller

@RequestMapping(path = "/editSchema/{id}")
public String editSchemaById(Model model, @PathVariable("id") Integer id)
{
    model.addAttribute("message", "why this isn't working...");
    return "redirect:/drawdiagram";
}

JavaScript drawdiagram.html

<script th:inline="javascript">
    /*<![CDATA[*/
    var message = /*[[${message}]]*/ 'default';
    /*]]>*/
</script>

Result

Anyony can tell me why i have null there?
I really don't know what is going on :(
Maybe this is bad way? I have chosen thymeleaf but maybe there is some other way?

All i need to do is:
1. Click button.
2. Execute some backend code and get data to variable in controller.
3. Redirect to other page.
4. Execute some JavaScript code which is based on that variable.

.

Sources:

1. https://www.thymeleaf.org/doc/tutorials/2.1/usingthymeleaf.html#script-inlining-javascript-and-dart
2. Setting up a JavaScript variable from Spring model by using Thymeleaf

Answer 1

you are redirecting to another controller drawdiagram, the values in model object won't be available in other controller. So here you need to set the value first using either RedirectAttributes#addFlashAttribute or RedirectAttributes#addAttribute, and then get the value in the other controller -using @ModelAttribute("message").

@RequestMapping(path = "/editSchema/{id}")
public String editSchemaById(Model model, @PathVariable("id") Integer id, RedirectAttributes redirectAttributes)
{
    redirectAttributes.addFlashAttribute("message", "why this isn't working...");
    return "redirect:/drawdiagram";
}

@RequestMapping(value = "drawdiagram", method = RequestMethod.GET)
public String OtherController(@ModelAttribute("message") String message, Model model) {
    model.addAttribute("message", message);
    return "drawdiagram";
}