如何解决 Spring JPA 不自动创建数据库表的问题

用 spring jpa 创建了一个 java 项目，然后增加 Student 类，并且标注为 @Enitity 如下：

package com.example.demojpa.models;

import javax.persistence.Entity;
import javax.persistence.Id;

@Entity
public class Student {
     

    @Id
    private Long Id;

    private String FirstName;

    private String LastName;

    public Student(Long id, String firstName, String lastName) {
     
        Id = id;
        FirstName = firstName;
        LastName = lastName;
    }

    public Long getId() {
     
        return Id;
    }

    public String getFirstName() {
     
        return FirstName;
    }

    public String getLastName() {
     
        return LastName;
    }

    public void setId(Long id) {
     
        Id = id;
    }

    public void setFirstName(String firstName) {
     
        FirstName = firstName;
    }

    public void setLastName(String lastName) {
     
        LastName = lastName;
    }
}

然后启动程序，查看数据库。数据库里没有新建student表，也没有在日志中看到创建 student 表的 SQL 语句。检查 application.yml 如下：

spring:
  datasource:
    driverClassName: com.microsoft.sqlserver.jdbc.SQLServerDriver
    url: jdbc:sqlserver://10.222.49.13;databaseName=demo;user=demo;password=demo;
  jpa:    
    hibernate:
      dll-auto: create-drop
    show-sql: true
    properties:
      hibernate:
        dialect: org.hibernate.dialect.SQLServerDialect
        format_sql: true

多次调试和搜索后后发现需要加上 jpa.generate-ddl: true。最后的 application.yml 如下所示：

spring:
  datasource:
    driverClassName: com.microsoft.sqlserver.jdbc.SQLServerDriver
    url: jdbc:sqlserver://10.222.49.13;databaseName=demo;user=demo;password=demo;
  jpa:
    generate-ddl: true # 需要加上这个才能自动生成数据库表
    hibernate:
      dll-auto: create-drop
    show-sql: true
    properties:
      hibernate:
        dialect: org.hibernate.dialect.SQLServerDialect
        format_sql: true