如何在SpringBoot2啟動(dòng)時(shí)自動(dòng)創(chuàng)建表、插入數(shù)據(jù)

一、springboot2中如何根據(jù)實(shí)體類自動(dòng)生成表

只需在類上添加@Entity注解。spring boot啟動(dòng)時(shí)會(huì)自動(dòng)生成user表（當(dāng)然，數(shù)據(jù)庫還得自己先創(chuàng)建）

import lombok.Data;

import javax.persistence.Entity;
import javax.persistence.Id;
import java.io.Serializable;

/**
 * @author chushiyan
 * @email Y2h1c2hpeWFuMDQxNUAxNjMuY29t(base64)
 * @description
 */
@Data
@Entity
public class User implements Serializable {

    @Id
    private String id;

    private String name;
}

對(duì)應(yīng)的application.yml：

server:
  port: 10000

spring:
  datasource:
    driverClassName: com.mysql.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/test?characterEncoding=utf-8
    username: root
    password: root
  jpa:
    database: MySQL
    show-sql: true
    generate-ddl: true

二、springboot2啟動(dòng)時(shí)如何向數(shù)據(jù)庫自動(dòng)插入數(shù)據(jù)

1、首先，在resources目錄下創(chuàng)建data.sql文件，例如：

INSERT INTO user (id,name) VALUES ('0','chushiyan');
INSERT INTO user (id,name) VALUES ('1','zhangsan');
INSERT INTO user (id,name) VALUES ('2','lisi');
INSERT INTO user (id,name) VALUES ('3','wangwu');

springboot啟動(dòng)時(shí)，會(huì)從classpath下讀取該文件，用來向數(shù)據(jù)庫的表插入數(shù)據(jù)。

2、然后，配置

spring.jpa.hibernate.ddl-auto=create-drop # 或者create
spring.datasource.initialization-mode=always

注：spring.jpa.hibernate.ddl-auto=create 或者 create-drop會(huì)先刪除已存在的表，主要用于測試。

完整application.yml：

server:
  port: 10000
spring:
  datasource:
    driverClassName: com.mysql.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/test?characterEncoding=utf-8
    username: root
    password: root
    initialization-mode: always
  jpa:
    database: MySQL
    show-sql: true
    generate-ddl: true
    hibernate:
      ddl-auto: create-drop 

三、如何讓SpringBoot2根據(jù)我們自定義的建表語句創(chuàng)建數(shù)據(jù)庫表

1、首先，在resources目錄下創(chuàng)建schema.sql文件，例如：

CREATE TABLE user (
    id   VARCHAR(128)      NOT NULL ,
    name VARCHAR(32)       NOT NULL,
    PRIMARY KEY (id)
);

springboot啟動(dòng)時(shí)，會(huì)從classpath下讀取該文件，用來創(chuàng)建數(shù)據(jù)庫表。

2、然后，配置：

spring.jpa.hibernate.ddl-auto=none

完整application.yml：

server:
  port: 10000
spring:
  datasource:
    driverClassName: com.mysql.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/test?characterEncoding=utf-8
    username: root
    password: root
    initialization-mode: always
  jpa:
    database: MySQL
    show-sql: true
    generate-ddl: true
    hibernate:
      ddl-auto: none 

驗(yàn)證是否使用了schema.sql文件創(chuàng)建表，查詢數(shù)據(jù)庫：

mysql> show create table user;
+-------+-----------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                                                                  |
+-------+-----------------------------------------------------------------------------------------------------------------------------------------------+
| user  | CREATE TABLE `user` (
  `id` varchar(128) NOT NULL,
  `name` varchar(32) NOT NULL,
  PRIMARY KEY  (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+-------+-----------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.01 sec)

mysql>