springboot 简单搭建(thymeleaf 视图显示)

<dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
    </dependencies>

spring:
  profiles:
    active: dev
  datasource:
    url: jdbc:mysql://ip地址:3306/testdb?serverTimezone=UTC
    username: root
    password: root
  jpa:
    generate-ddl: false
    hibernate:
      ddl-auto: none
    show-sql: true
  thymeleaf:
    prefix: classpath:/templates/
    suffix: .html
    mode: HTML5
    encoding: UTF-8
    cache: false
    servlet:
      content-type: text/html

server:
  servlet:
    context-path:
  port: 8081

@SpringBootApplication
public class DemoApplication {
 
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
 
}

@Entity
@Table(name = "user", catalog = "testdb")
@DynamicUpdate
public class User {
    private Integer id;
    private String uuid;
    private String userName;
    private String password;
    private Date createTime;
    private Integer age;
 
    @Id
    @GeneratedValue
    @Column(name = "id")
    public Integer getId() {
        return id;
    }
 
    public void setId(Integer id) {
        this.id = id;
    }
 
    @Column(name = "uuid")
    public String getUuid() {
        return uuid;
    }
 
    public void setUuid(String uuid) {
        this.uuid = uuid;
    }
 
    @Column(name = "username")
    public String getUserName() {
        return userName;
    }
 
    public void setUserName(String userName) {
        this.userName = userName;
    }
 
    @Column(name = "password")
    public String getPassword() {
        return password;
    }
 
    public void setPassword(String password) {
        this.password = password;
    }
 
    @Column(name = "createtime")
    public Date getCreateTime() {
        return createTime;
    }
 
    public void setCreateTime(Date createTime) {
        this.createTime = createTime;
    }
 
    @Column(name = "age")
    public Integer getAge() {
        return age;
    }
 
    public void setAge(Integer age) {
        this.age = age;
    }
}

@Repository
public interface UserRepository extends JpaRepository<User,Integer> {
}

@Controller
public class HelloController {
 
    @Autowired
    UserRepository userRepository;
 
    @RequestMapping("/index.do")
    public String say(ModelMap mode) {
        User user=userRepository.findById(3).get();
        mode.addAttribute("user", user);
        return "say";
    }
}

<span th:text="${user.userName}"></span>
hello
</body>