spring boot hibernate自动创建表

ゝ一纸荒年。 2022-09-30 13:45 157阅读 0赞

pom文件  
<?xml version="1.0" encoding="UTF-8"?>  
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">  
<modelVersion>4.0.0</modelVersion>  
  
<groupId>com.bootsqltest</groupId>  
<artifactId>bootHibernate</artifactId>  
<version>0.0.1-SNAPSHOT</version>  
<packaging>jar</packaging>  
  
<name>bootHibernate</name>  
<description>Demo project for Spring Boot</description>  
  
<parent>  
<groupId>org.springframework.boot</groupId>  
<artifactId>spring-boot-starter-parent</artifactId>  
<version>1.5.2.RELEASE</version>  
<relativePath />   
</parent>  
  
<properties>  
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>  
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>  
<java.version>1.8</java.version>  
</properties>  
  
<dependencies>  
<dependency>  
<groupId>org.springframework.boot</groupId>  
<artifactId>spring-boot-starter-data-jpa</artifactId>  
</dependency>  
<dependency>  
<groupId>mysql</groupId>  
<artifactId>mysql-connector-java</artifactId>  
</dependency>  
<dependency>  
<groupId>org.springframework.boot</groupId>  
<artifactId>spring-boot-starter-web</artifactId>  
</dependency>  
  
<dependency>  
<groupId>org.springframework.boot</groupId>  
<artifactId>spring-boot-starter-test</artifactId>  
<scope>test</scope>  
</dependency>  
</dependencies>  
  
<build>  
<plugins>  
<plugin>  
<groupId>org.springframework.boot</groupId>  
<artifactId>spring-boot-maven-plugin</artifactId>  
</plugin>  
</plugins>  
</build>

</project>

创建一个实体类

@Entity  
@Table(name = "t\_user")  
public class User \{  
  
@Id  
@GeneratedValue(strategy = GenerationType.AUTO)  
private Integer id;  
  
@Column(name = "user\_name")  
private String userName;  
  
private String password;  
  
@Column(name = "nick\_name")  
private String nickName;  
  
private String email;  
  
public Integer getId() \{  
return id;  
\}  
  
public void setId(Integer id) \{  
this.id = id;  
\}  
  
public String getUserName() \{  
return userName;  
\}  
  
public void setUserName(String userName) \{  
this.userName = userName;  
\}  
  
public String getPassword() \{  
return password;  
\}  
  
public void setPassword(String password) \{  
this.password = password;  
\}  
  
public String getNickName() \{  
return nickName;  
\}  
  
public void setNickName(String nickName) \{  
this.nickName = nickName;  
\}  
  
public String getEmail() \{  
return email;  
\}  
  
public void setEmail(String email) \{  
this.email = email;  
\}

application.properties配置

\#端口  
server.port=80  
\#\# 自动扫描的包前缀  
entitymanager.packagesToScan= com.xyd  
\#\# 显示Sql  
hibernate.show\_sql=true  
\#\# 数据库连接  
spring.datasource.url=jdbc:mysql://localhost:3306/自己新建一个数据库?useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true  
\#\# 用户名  
spring.datasource.username=root  
\#\# 密码  
spring.datasource.password=root  
\#\# 数据库驱动  
spring.datasource.driver-class-name=com.mysql.jdbc.Driver  
\#\# 建表方式有四种 一般update方式  
create：每次加载Hibernate时都会删除上一次生成的表，然后重新生成新表，即使两次没有任何修改也会这样执行，这就导致每次启动都是一个新的数据库，也是导致数据丢失的重要原因  
create-drop：每次加载Hibernate时都会生成表，但当SessionFactory关闭时，所生成的表将自动删除  
update：最常用的属性值，第一次加载Hibernate时创建数据表（前提是需要先有数据库），以后加载HIbernate时只会根据model更新，即使model已经删除了某些属性，数据表也不会随之删除字段。  
validate：每次加载Hibernate时都会验证数据表结构，只会和已经存在的数据表进行比较，根据model修改表结构，但不会创建新表。  
spring.jpa.properties.hibernate.hbm2ddl.auto=update  
\# 方言

spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect

最后启动服务