How to send a Thymeleaf input value as a request parameter to controller in Java Spring?

Question

I am using Thymeleaf forms and traditional Spring rest controllers to make API requests to an external platform.

The Thymeleaf form is a simple login form with 2 fields and a submit button. After the user presses submit, the data from the 2 fields needs to be sent as request parameters to a GET mapping method inside the controller.

What's the easiest way to achieve this?

Thanks

Answer 1

To send data from a Thymeleaf form to a Spring REST controller as request parameters and POST mapping, you can follow these example:

<form th:action="@{/login}" method="post">
<label>Username: <input type="text" name="username"></label><br>
<label>Password: <input type="password" name="password"></label><br>
<button type="submit">Login</button>
</form>

and for Controller

   @Controller
   public class LoginController {
    @PostMapping("/login")
    public String login(@RequestParam String username, @RequestParam String password, Model model) {
        if ("admin".equals(username) && "admin".equals(password)) {
            System.out.printf("username:%s and password:%s", username, password);
            model.addAttribute("username", username);
            return "redirect:/success";
        }

        model.addAttribute("error", "Invalid username or password");
        return "login";
    }
}

and you can post data with

http://localhost:8080/login?username=admin&password=admin