如何从控制器以图像形式获取变量值？

Question

所以我有一个带有图像类型输入的表单，此表单中有7张图像，每个图像都有一个具有不同值的变量，我想将此变量传递给带有@PostMapping批注的controller方法，该怎么做？以及如何仅使用一种控制器方法来制作它？

// the form 

<table>
    <form th:action="@{/home/lab}" method="post">
        <tr>
            <td>
                <div>
                    <center>
                        <input type="image" class="cornered-img" th:src="@{/images/labs/test1.png}" name="lab" value="test1" >
                    </center>
                </div>
            </td>
            <td>
                <div>
                    <center>
                        <input type="image" class="cornered-img" th:src="@{/images/labs/test2.png}" name="lab" value="test2">
                    </center>
                </div>
            </td>
            <td>
                <div>
                    <center>
                        <input type="image" class="cornered-img" th:src="@{/images/labs/test3.png}" name="lab" value="test3">
                    </center>
                </div>
            </td>
        </tr>
        <tr>
            <td>
                <div>
                    <center>
                        <input type="image" class="cornered-img" th:src="@{/images/labs/test4.png}" name="lab" value="test4">
                    </center>
                </div>
            </td>
            <td>
                <div>
                    <center>
                        <input type="image" class="cornered-img" th:src="@{/images/labs/test5.png}" name="lab" value="test5">
                    </center>
                </div>
            </td>
            <td>
                <div>
                    <center>
                        <input type="image" class="cornered-img" th:src="@{/images/labs/test6.png}" name="lab" value="test6">
                    </center>
                </div>
            </td>
        </tr>
        <tr>
            <td>
            </td>
            <td>
                <div>
                    <center>
                        <input type="image" class="cornered-img" th:src="@{/images/labs/test7.png}" name="lab" value="test7">
                    </center>
                </div>
            </td>
            <td>
            </td>
        </tr>
    </form>
</table>

// the controller
    @PostMapping("/lab")
    public String toLab(@ModelAttribute("user") User user, String lab, Model model){
        log.info(lab);
        model.addAttribute("lab", lab);
        return "redirect:/lab";
    }

控制器中的参数“ lab”为空。