我目前正在学习Sping Boot ，并尝试使用MySQL数据库设置JPA。一切看起来都很好，项目正确启动，没有可见的错误，但是. ProjectApplication.java

package com.first.project;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class ProjectApplication {

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

}

字符串
我的学生班级：

package com.first.project.student;

import org.springframework.data.annotation.Id;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Table;
import java.time.LocalDate;

@Entity
@Table
public class Student {
  @Id
  @GeneratedValue(
          strategy = GenerationType.IDENTITY
  )
  private Long id;
  private String name;
  private String email;
  private LocalDate dateOfBirth;
  private Integer age;

  public Student() {
  }
  public Student(Long studentId, String studentName, String studentEmail, LocalDate studentDoB, Integer studentAge) {
    this.id = studentId;
    this.name = studentName;
    this.email = studentEmail;
    this.dateOfBirth = studentDoB;
    this.age = studentAge;
  }

  public Student(String studentName, String studentEmail, LocalDate studentDoB, Integer studentAge) {
    this.name = studentName;
    this.email = studentEmail;
    this.dateOfBirth = studentDoB;
    this.age = studentAge;
  }

  public Long getId() {
    return id;
  }

  public void setId(Long id) {
    this.id = id;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }

  public String getEmail() {
    return email;
  }

  public void setEmail(String email) {
    this.email = email;
  }

  public LocalDate getDateOfBirth() {
    return dateOfBirth;
  }

  public void setDateOfBirth(LocalDate dateOfBirth) {
    this.dateOfBirth = dateOfBirth;
  }

  public Integer getAge() {
    return age;
  }

  public void setAge(Integer age) {
    this.age = age;
  }

  @Override
  public String toString() {
    return "Student{" +
            "id=" + id +
            ", name='" + name + '\'' +
            ", email='" + email + '\'' +
            ", dateOfBirth=" + dateOfBirth +
            ", age=" + age +
            '}';
  }
}

型
application.properties:

spring.datasource.url=jdbc:mysql://localhost:3306/(my database)
spring.datasource.username=(my username)
spring.datasource.password=(my password)
spring.jpa.hibernate.ddl-auto=create-drop
spring.jpa.show-sql=true
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQLDialect
spring.jpa.properties.hibernate.format_sql=true
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.jpa.properties.hibernate.show_sql=true
spring.jpa.generate-ddl=true

型
我的pom.xml文件中的依赖项：

<dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </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>javax.persistence</groupId>
            <artifactId>javax.persistence-api</artifactId>
            <version>2.2</version>
        </dependency>
    </dependencies>

型
在主包中我有ProjectApplication，还有一个子包，里面有Student类。
有什么想法吗？