springboot 表单校验

@Entity
public class User implements Serializable {

    /**
     * 编号
     */
    @Id
    @GeneratedValue
    private Long id;

    /**
     * 名称
     */
    @NotEmpty(message = "姓名不能为空")
    @Size(min = 2, max = 8, message = "姓名长度必须大于 2 且小于 20 字")
    private String name;

    /**
     * 年龄
     */
    @NotNull(message = "年龄不能为空")
    @Min(value = 0, message = "年龄大于 0")
    @Max(value = 300, message = "年龄不大于 300")
    private Integer age;

    /**
     * 出生时间
     */
    @NotEmpty(message = "出生时间不能为空")
    private String birthday;

　　....//省略

}

<form th:action="@{/users/{action}(action=${action})}" method="post" class="form-horizontal">

                <input type="hidden" name="id" th:value="${user.id}"/>

                <div class="form-group">
                    <label for="user_name" class="col-sm-2 control-label">名称:</label>
                    <div class="col-xs-4">
                        <input type="text" class="form-control" id="user_name" name="name" th:value="${user.name}" th:field="*{user.name}" />
                    </div>
                    <label class="col-sm-2 control-label text-danger" th:if="${#fields.hasErrors('user.name')}" th:errors="*{user.name}">姓名有误!</label>
                </div>

                <div class="form-group">
                    <label for="user_age" class="col-sm-2 control-label">年龄:</label>
                    <div class="col-xs-4">
                        <input type="text" class="form-control" id="user_age" name="age" th:value="${user.age}" th:field="*{user.age}" />
                    </div>
                    <label class="col-sm-2 control-label text-danger" th:if="${#fields.hasErrors('user.age')}" th:errors="*{user.age}">年龄有误!</label>
                </div>

                <div class="form-group">
                    <label for="user_birthday" class="col-sm-2 control-label">出生日期:</label>
                    <div class="col-xs-4">
                        <input type="date" class="form-control" id="user_birthday" name="birthday" th:value="${user.birthday}" th:field="*{user.birthday}"/>
                    </div>
                    <label class="col-sm-2 control-label text-danger" th:if="${#fields.hasErrors('user.birthday')}" th:errors="*{user.birthday}">生日有误!</label>
                </div>

                <div class="form-group">
                    <div class="col-sm-offset-2 col-sm-10">
                        <input class="btn btn-primary" type="submit" value="提交"/>&nbsp;&nbsp;
                        <input class="btn" type="button" value="返回" onclick="history.back()"/>
                    </div>
                </div>
            </form>

    @RequestMapping(value = "/create", method = RequestMethod.POST)
    public String postUser(ModelMap map,
                           @ModelAttribute @Valid User user,
                           BindingResult bindingResult) {

        if (bindingResult.hasErrors()) {
            map.addAttribute("action", "create");
            return "userForm";
        }

        userService.insertByUser(user);

        return "redirect:/users/";
    }