数据库

spring-data-jpa

1. Maven 添加两个组件

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

2. 添加配置

spring:
  profiles:
    active: dev
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/test?&serverTimezone=UTC&characterEncoding=utf8&useSSL=false
    username: root
    password: root
  jpa:
    hibernate:
      ddl-auto: create
    show-sql: true

jpa.hibernate.ddl-auto 的参数

ddl-auto:create----每次运行该程序，没有表格会新建表格，有表会删除表再创建表。

ddl-auto:create-drop----每次程序结束的时候会清空表

ddl-auto:update----每次运行程序，没有表格会新建表格，表内有数据不会清空，只会更新

ddl-auto:validate----运行程序会校验数据与数据库的字段类型是否相同，不同会报错

创建表结构

package cn.asdasd.demo;

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

@Entity
public class Girl {
    @Id
    @GeneratedValue
    private Integer id;
    private String cupSize;
    private Integer age;

    public Girl(){

    }

    public Integer getId() {
        return id;
    }

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

    public String getCupSize() {
        return cupSize;
    }

    public void setCupSize(String cupSize) {
        this.cupSize = cupSize;
    }

    public Integer getAge() {
        return age;
    }

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

==注意要加 @Entity 注解==