まずは公式に従う。≫ https://spring.io/guides/gs/securing-web/pom.xmlにjpaとsecurityを追加。 <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-security<…</artifactid></dependency>