Springboot如何根據(jù)實(shí)體類生成數(shù)據(jù)庫(kù)表

更新時(shí)間：2021年09月11日 15:25:01 作者：Insist_on_progress

這篇文章主要介紹了Springboot如何根據(jù)實(shí)體類生成數(shù)據(jù)庫(kù)表的操作，具有很好的參考價(jià)值，希望對(duì)大家有所幫助。如有錯(cuò)誤或未考慮完全的地方，望不吝賜教

Springboot 實(shí)體類生成數(shù)據(jù)庫(kù)表

JPA:springboot -jpa:數(shù)據(jù)庫(kù)的一系列的定義數(shù)據(jù)持久化的標(biāo)準(zhǔn)的體系

學(xué)習(xí)的目的是：

利用springboot實(shí)現(xiàn)對(duì)數(shù)據(jù)庫(kù)的操作

第一步：添加springboot-data-jpa和數(shù)據(jù)庫(kù)的依賴關(guān)系

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

第二步：編寫yml文件的配置

server:
  port: 8001
spring:
  application:
    name: jih-manage
  datasource:
    name: test
    url: jdbc:mysql://111.231.231.56/jih
    username: root
    password: root
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: com.mysql.jdbc.Driver
  jpa:
    hibernate:
      ddl-auto: update
    show-sql: true

第三步：實(shí)體類中使用的注解

@Entity 實(shí)體類的注解
@Id 映射到表格中id的屬性
@Gernertervalue 添加其自增的屬性

第四步：?jiǎn)?dòng)項(xiàng)目是否生成表格

補(bǔ)充的知識(shí)點(diǎn)：

根據(jù)實(shí)體類生成數(shù)據(jù)庫(kù)的表配置文件有倆種方式分別是yml和properties文件進(jìn)行配置

yml文件：

spring:
    datasource:
        driver-class-name:  com.mysql.jdbc.Driver
        url: jdbc:mysql://127.0.0.1:3306/facemap
        username: root
        password: root
    jpa:
        hibernate:
            ddl-auto: update
            show-sql: true

properties文件的寫法：

spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/dbgirl?characterEncoding=utf8
spring.datasource.username=root
spring.datasource.password=root
spring.jpa.show-sql= true
spring.jpa.hibernate.ddl-auto=update
spring.jpa.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect
spring.jackson.serialization.indent_output=false

有更加詳細(xì)介紹

參考網(wǎng)址：

//m.fzitv.net/article/222622.htm

實(shí)體類的寫法：

package com.example.demo;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
@Entity //實(shí)體類的注解
public class Girl {
    @Id //@id注意選擇這個(gè)javax.persistence
    @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;
    }
}

第五步：?jiǎn)?dòng)項(xiàng)目即可

完成~

springboot繼承JPA根據(jù)實(shí)體類生成數(shù)據(jù)庫(kù)中的表

首先搭建springboot框架。搭建完成之后：

1. pom中添加的依賴

<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>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.1</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
 
        <!--mysql-connection-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.15</version>
        </dependency>
 
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

2. application.yml中配置jpa配置

server:
  port: 8080
 
spring:
  datasource:
    type: com.zaxxer.hikari.HikariDataSource
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/h5mall?useUnicode=true&characterEncoding=utf-8&useSSL=false
    username: root
    password: 123456
    hikari:
      minimum-idle: 5
      idle-timeout: 180000
      maximum-pool-size: 10
      auto-commit: true
      pool-name: MyHikariCP
      connection-timeout: 30000
  jpa:
    hibernate:
      ddl-auto: update
    show-sql: true

其中jpa下的jpa.hibernate.ddl-auto屬性值有如下：

ddl-auto:create （每次運(yùn)行該程序，沒(méi)有表格會(huì)新建表格，表內(nèi)有數(shù)據(jù)會(huì)清空）
ddl-auto:create-drop （每次程序結(jié)束的時(shí)候會(huì)清空表）
ddl-auto:update （每次運(yùn)行程序，沒(méi)有表格會(huì)新建表格，表內(nèi)有數(shù)據(jù)不會(huì)清空，只會(huì)更新）
ddl-auto:validate（運(yùn)行程序會(huì)校驗(yàn)數(shù)據(jù)與數(shù)據(jù)庫(kù)的字段類型是否相同，不同會(huì)報(bào)錯(cuò)）

一般情況下選擇update，其他屬性值慎用！

定義用戶實(shí)體類，通過(guò)注解映射成數(shù)據(jù)庫(kù)中的表

 
import javax.persistence.*; 
@Entity
@Table(name = "user")
@Data
public class User {
 
    @Id
    @GeneratedValue
    private Long id;
 
    //name屬性為表的字段名。length為字段的長(zhǎng)度
    @Column(length = 30, name = "userId")
    private String userId;
 
    @Column(name = "userName", length = 20, columnDefinition="varchar(100) COMMENT '用戶名'")
    private String userName;
 
    @Column(name = "phone", length = 20)
    private String phone;
 
    @Column(name = "password", length = 30)
    private String password;
 
    @Column(name = "userRealName", length = 20)
    private String userRealName;
 
    @Column(name = "address", length = 20)
    private String address;
}