SpringBootでバリデーションが機能しない

前提・実現したいこと

SpringBootを利用して以下書籍を参考にしながら、サンプルWebアプリケーションを作成しているのですが、バリデーションがうまく作動せず、空白文字で遷移してもエラーメッセージを出力してくれません。
アノテーションを読み込めていないのかなと思っているのですが、原因がわからずお力貸していただけませんでしょうか。
参考書籍：https://www.amazon.co.jp/%E5%BE%8C%E6%82%94%E3%81%97%E3%81%AA%E3%81%84%E3%81%9F%E3%82%81%E3%81%AESpring-Boot-%E5%85%A5%E9%96%80%E6%9B%B8%EF%BC%9ASpring-%E8%A7%A3%E4%BD%93%E6%96%B0%E6%9B%B8%EF%BC%88%E7%AC%AC2%E7%89%88%EF%BC%89Spring-Boot%E3%81%8C%E4%B8%B8%E5%88%86%E3%81%8B%E3%82%8A/dp/4802092865/ref=pd_sbs_5/356-0278638-6666779?pd_rd_w=rxjRj&pf_rd_p=367c54b8-500b-4071-9b4d-65fe16192688&pf_rd_r=0KA5Z16ZFCX9895224E9&pd_rd_r=b2f7ab7a-bfb1-4394-9d20-431346055658&pd_rd_wg=DeGyN&pd_rd_i=4802092865&psc=1

発生している問題・エラーメッセージ

・入力フォームに空白もしくはNullが入力されている際に、バリテーションでエラーメッセージを出力したいが、うまく機能せず、正常稼働時と同様の画面遷移になってしまう。

該当のソースコード

pom
1<?xml version="1.0" encoding="UTF-8"?>
2<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
3	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
4	<modelVersion>4.0.0</modelVersion>
5	<parent>
6		<groupId>org.springframework.boot</groupId>
7		<artifactId>spring-boot-starter-parent</artifactId>
8		<version>2.5.2</version>
9		<relativePath/> <!-- lookup parent from repository -->
10	</parent>
11	<groupId>com.example</groupId>
12	<artifactId>SpringBootSample</artifactId>
13	<version>0.0.1-SNAPSHOT</version>
14	<name>SpringBootSample</name>
15	<description>Demo project for Spring Boot</description>
16	<properties>
17		<java.version>11</java.version>
18	</properties>
19	<dependencies>
20		<dependency>
21			<groupId>org.springframework.boot</groupId>
22			<artifactId>spring-boot-starter-data-jdbc</artifactId>
23		</dependency>
24		<dependency>
25			<groupId>org.springframework.boot</groupId>
26			<artifactId>spring-boot-starter-jdbc</artifactId>
27		</dependency>
28		<dependency>
29			<groupId>org.springframework.boot</groupId>
30			<artifactId>spring-boot-starter-thymeleaf</artifactId>
31		</dependency>
32		<dependency>
33			<groupId>org.springframework.boot</groupId>
34			<artifactId>spring-boot-starter-web</artifactId>
35		</dependency>
36		<dependency>
37			<groupId>org.springframework.boot</groupId>
38			<artifactId>spring-boot-devtools</artifactId>
39			<scope>runtime</scope>
40			<optional>true</optional>
41		</dependency>
42		<dependency>
43			<groupId>com.h2database</groupId>
44			<artifactId>h2</artifactId>
45			<scope>runtime</scope>
46		</dependency>
47		<dependency>
48			<groupId>org.projectlombok</groupId>
49			<artifactId>lombok</artifactId>
50			<optional>true</optional>
51		</dependency>
52		<dependency>
53			<groupId>org.springframework.boot</groupId>
54			<artifactId>spring-boot-starter-test</artifactId>
55			<scope>test</scope>
56		</dependency>
57		<!-- query -->
58		<dependency>
59			<groupId>org.webjars</groupId>
60			<artifactId>jquery</artifactId>
61			<version>3.5.1</version>
62		</dependency>
63		<!-- bootstrap -->
64		<dependency>
65			<groupId>org.webjars</groupId>
66			<artifactId>bootstrap</artifactId>
67			<version>4.5.3</version>
68		</dependency>
69		<!-- webjars-locator -->
70		<dependency>
71			<groupId>org.webjars</groupId>
72			<artifactId>webjars-locator</artifactId>
73			<version>0.40</version>
74		</dependency>
75		<!-- validator -->
76		<dependency>
77			<groupId>org.springframework.boot</groupId>
78			<artifactId>spring-boot-starter-validation</artifactId>
79		</dependency>
80	</dependencies>
81
82	<build>
83		<plugins>
84			<plugin>
85				<groupId>org.springframework.boot</groupId>
86				<artifactId>spring-boot-maven-plugin</artifactId>
87				<configuration>
88					<excludes>
89						<exclude>
90							<groupId>org.projectlombok</groupId>
91							<artifactId>lombok</artifactId>
92						</exclude>
93					</excludes>
94				</configuration>
95			</plugin>
96		</plugins>
97	</build>
98
99</project>

Form
1package com.example.form;
2
3import java.util.Date;
4
5import javax.validation.constraints.Email;
6import javax.validation.constraints.Max;
7import javax.validation.constraints.Min;
8import javax.validation.constraints.NotBlank;
9import javax.validation.constraints.NotNull;
10import javax.validation.constraints.Pattern;
11
12import org.hibernate.validator.constraints.Length;
13import org.springframework.format.annotation.DateTimeFormat;
14
15import lombok.Data;
16
17@Data
18public class SignupForm {
19	
20	@NotBlank
21	@Email
22	private String userId;
23	
24	@NotBlank
25	@Length(min=4,max=100)
26	@Pattern(regexp="^[a-zA-Z0-9]+$")
27	private String password;
28	
29	@NotBlank
30	private String userName;
31	
32	@DateTimeFormat(pattern = "yyyy/MM/dd")
33	@NotNull
34	private Date birthday;
35	
36	@Min(20)
37	@Max(100)
38	private Integer age;
39	
40	@NotNull
41	private Integer gender;
42
43}

Controller
1package com.example.controller;
2
3import java.util.Locale;
4import java.util.Map;
5
6import org.springframework.beans.factory.annotation.Autowired;
7import org.springframework.stereotype.Controller;
8import org.springframework.ui.Model;
9import org.springframework.validation.BindingResult;
10import org.springframework.validation.annotation.Validated;
11import org.springframework.web.bind.annotation.GetMapping;
12import org.springframework.web.bind.annotation.ModelAttribute;
13import org.springframework.web.bind.annotation.PostMapping;
14import org.springframework.web.bind.annotation.RequestMapping;
15
16import com.example.application.service.UserApplicationService;
17import com.example.form.SignupForm;
18
19import lombok.extern.slf4j.Slf4j;
20
21@Controller
22@RequestMapping("/user")
23@Slf4j
24public class SignupController {
25	@Autowired
26	private UserApplicationService userApplicationService;
27	
28	//** ユーザ登録画面を表示 */
29	@GetMapping("signup")
30	public String getSignup(Model model,Locale locale,@ModelAttribute SignupForm form) {
31		//性別を取得
32		Map<String,Integer> genderMap=userApplicationService.getGenderMap(locale);
33		model.addAttribute("genderMap",genderMap);
34		
35		//ユーザ登録画面に遷移
36		return "user/signup";
37	}
38	
39	/** ユーザ登録処理 */
40	@PostMapping("/signup")
41	public String postSignup(Model model,Locale locale,@ModelAttribute @Validated SignupForm form, BindingResult bindingResult) {
42		
43		//入力チェック結果
44		if(bindingResult.hasErrors()) {
45			//NG:ユーザ登録画面に戻ります
46			return getSignup(model,locale,form);
47		}
48		log.info("has error: {}", bindingResult.getFieldError());
49		log.info(form.toString());
50		
51		// ログイン画面にリダイレクト
52		return "redirect:/login";
53	}
54}
55

html
1<!DOCTYPE html>
2<html xmlns:th="http://www.thymeleaf.org">
3<head>
4	<meta charset="UTF-8"></meta>
5	<meta name="viewpoint" content="width=device-width,initial-scale=1,shrink-to-fit=no">
6	<!-- CSS読込 -->
7	<link rel="stylesheet" th:href="@{/webjars/bootstrap/css/bootstrap.min.css}">
8	<link rel="stylesheet" th:href="@{/css/user/signup.css}">
9	<!-- JS読込 -->
10	<script th:src="@{/webjars/jquery/jquery.min.js}" defer></script>
11	<script th:src="@{/webjars/bootstrap/bootstrap.min.js}" defer></script>
12	<title th:text="#{user.signup.title}"></title>
13</head>
14<body class="bg-light">
15	<form id="signup-form" method="post" action="/user/signup" class="form-signup" th:object="${signupForm}">
16		<h1 class="text-center" th:text="#{user.signup.title}"></h1>
17		<!-- ユーザID -->
18		<div class="form-group">
19			<label for="userId" th:text="#{userId}"></label>
20			<input type="text" class="form-control" th:field="*{userId}" th:errorclass="is-invalid"/>
21			<div class="invalid-feedback" th:errors="*{userId}"></div>
22		</div>
23		<!-- パスワード -->
24		<div class="form-group">
25			<label for="password" th:text="#{password}"></label>
26			<input type="text" class="form-control" th:field="*{password}" th:errorclass="is-invalid"/>
27			<div class="invalid-feedback" th:errors="*{password}"></div>
28		</div>	
29		<!-- ユーザ名 -->
30		<div class="form-group">
31			<label for="userName" th:text="#{userName}"></label>
32			<input type="text" class="form-control" th:field="*{userName}" th:errorclass="is-invalid"/>
33			<div class="invalid-feedback" th:errors="*{userName}"></div>
34		</div>
35		<!-- 誕生日 -->
36		<div class="form-group">
37			<label for="birthday" th:text="#{birthday}"></label>
38			<input type="text" placeholder="yyyy/mm/dd" class="form-control" th:field="*{birthday}" th:errorclass="is-invalid"/>
39			<div class="invalid-feedback" th:errors="*{birthday}"></div>
40		</div>
41		<!-- 年齢 -->
42		<div class="form-group">
43			<label for="age" th:text="#{age}"></label>
44			<input type="text" class="form-control" th:field="*{age}" th:errorclass="is-invalid"/>
45			<div class="invalid-feedback" th:errors="*{age}"></div>
46		</div>
47		<!-- 性別 -->
48		<div class="form-group">
49			<div th:each="item:${genderMap}" class="form-check-inline">
50			<input type="radio" class="form-check-input" th:value="${item.value}" th:field="*{gender}" th:errorclass="is-invalid"/>
51			<label class="form-check-label" th:text="${item.key}"></label>
52			<div class="text-danger" th:if="${#fields.hasErrors('gender')}" th:errors="*{gender}"></div>
53			</div>
54		</div>
55		<!-- 登録ボタン -->
56		<input type="submit" th:value="#{user.signup.btn}" class="btn btn-primary w-100 mt-3" />
57	</form>
58</body>
59</html>