一、关于pom文件的配置
<!-- 引入mysql依赖-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<!--引入druid连接池依赖 -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.1.10</version>
</dependency>
<!--引入lombok依赖-->
<!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.8</version>
<scope>provided</scope>
</dependency>
二、目录结构(注意结构不同也有可能导致无法自动建表)
三、application.properties文件的配置
#注意springboot2.0以下的写法是:server.context-path
server.servlet.context-path=/helloworld
#配置服务器的端口
server.port=8080
#配置数据源
#db config
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.driverClassName=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/schooltest?useSSL=false&useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.initialSize=20
spring.datasource.minIdle=50
spring.datasource.maxActive=500
#配置jpa
#帮我们自动生成表结构
spring.jpa.properties.hibernate.hbm2ddl.auto=update
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
spring.jpa.show-sql=true
spring.jpa.properties.hibernate.enable_lazy_load_no_trans=true
四、Users实体类的配置
@Data
@NoArgsConstructor
@AllArgsConstructor
@Entity
@Table(name = "USERS")
public class Users {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private int uid;
@Column(length = 2)//限定该参数的长度为2
private String gender;
private String username;
private String password;
private String birthday;
private String avatar;
}
五、注意事项
如果第一次没有按照以上标准配置自动建表,可能导致建好的表中没有自动添加主键或者没有自动递增,建议先把表删除,再重新运行代码。