@PostMapping("test")
    public String aaa(Model model) {
        List<User> users = new ArrayList<>();
        users.add(new User("bb", "11"));
        users.add(new User("cc", "22"));
        users.add(new User("dd", "33"));
        users.add(new User("ee", "44"));
        model.addAttribute("users",users);

        return "index::userinfo";
    }

<div class="userinfo" th:fragment="userinfo">
    用户信息
    <div th:each="user : ${users}">
            姓名:
            <span th:text="${user.name}"></span>
            年龄:
            <span th:text="${user.age}"></span>

    </div>
</div>
<input type="button" id="btn" value="点击展示用户">

<script src="https://code.jquery.com/jquery-3.1.1.min.js"></script>
<script>
    $('#btn').click(function () {
        var url = '/test';
        $.ajax({
            url: url,
            type: 'POST',
            success: function (data) {
                $(".userinfo").html(data);
            }
        })
    })
    //两种都可以
    $('#btn').click(function () {
        var url = '/test';
        $('.userinfo').load(url);
    });
</script>