问题

项目使用了MySQL数据库和Open Server。以下是我的application.properties文件：

spring.jpa.hibernate.ddl-auto=update
spring.datasource.url=jdbc:mysql://${MYSQL_HOST:localhost}:8888/citatnik_bd
spring.datasource.username=root
spring.datasource.password=
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
#spring.jpa.show-sql: true

这是我的实体类：

import javax.persistence.*;

@Entity
@Table(name="Quotes")
public class Quotes {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long ID;

    private String ru, by, ua, en;

    public Long GetID() { return ID; }
    public void SetID(Long ID) { this.ID = ID; }

    public String GetBy() { return by; }
    public void SetBy(String by) { this.by = by; }

    public String GetRu() { return ru; }
    public void SetRu(String ru) { this.ru = ru; }

    public String GetUa() { return ua; }
    public void SetUa(String ua) { this.ua = ua; }

    public String GetEn() { return en; }
    public void SetEn(String en) { this.by = en; }
}

顺便提一下，pom.xml文件中的所有必要依赖项都正确注册：

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>3.1.2</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.Citatnik</groupId>
	<artifactId>Citatnik</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>Citatnik</name>
	<description>Citatnik project</description>
	<properties>
		<java.version>17</java.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-thymeleaf</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-data-jpa</artifactId>
		</dependency>
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<scope>runtime</scope>
			<version>8.0.30</version>
		</dependency>
		<dependency>
			<groupId>javax.persistence</groupId>
			<artifactId>javax.persistence-api</artifactId>
			<version>2.2</version>
		</dependency>


		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-devtools</artifactId>
			<scope>runtime</scope>
			<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>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>


</project>

这是Spring应用程序的日志输出：

:: Spring Boot :: (v3.1.2)
2023-07-31T19:01:34.457+03:00 INFO 3336 --- [ restartedMain] c.Citatnik.Citatnik.CitatnikApplication : Starting CitatnikApplication using Java 17.0.6 with PID 3336 (C:\Users\dddry\OneDrive\Рабочий стол\Цитатник\Citatnik\target\classes started by dddry in C:\Users\dddry\OneDrive\Рабочий стол\Цитатник\Citatnik)
2023-07-31T19:01:34.461+03:00 INFO 3336 --- [ restartedMain] c.Citatnik.Citatnik.CitatnikApplication : No active profile set, falling back to 1 default profile: "default"
2023-07-31T19:01:34.539+03:00 INFO 3336 --- [ restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : Devtools property defaults active! Set 'spring.devtools.add-properties' to 'false' to disable
2023-07-31T19:01:34.539+03:00 INFO 3336 --- [ restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : For additional web related logging consider setting the 'logging.level.web' property to 'DEBUG'
2023-07-31T19:01:35.213+03:00 INFO 3336 --- [ restartedMain] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data JPA repositories in DEFAULT mode.
2023-07-31T19:01:35.232+03:00 INFO 3336 --- [ restartedMain] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 11 ms. Found 0 JPA repository interfaces.
2023-07-31T19:01:35.866+03:00 INFO 3336 --- [ restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2023-07-31T19:01:35.876+03:00 INFO 3336 --- [ restartedMain] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2023-07-31T19:01:35.876+03:00 INFO 3336 --- [ restartedMain] o.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/10.1.11]
2023-07-31T19:01:35.945+03:00 INFO 3336 ---
<details>
<summary>英文:</summary>
The project uses a database MySql, Open Server. Here is my application.properties file:

spring.jpa.hibernate.ddl-auto=update
spring.datasource.url=jdbc:mysql://${MYSQL_HOST:localhost}:8888/citatnik_bd
spring.datasource.username=root
spring.datasource.password=
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
#spring.jpa.show-sql: true

Here is my entity:

import javax.persistence.*;

@Entity
@Table(name="Quotes")
public class Quotes {

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long ID;
private String ru, by, ua, en;
public Long GetID() { return ID; }
public void SetID(Long ID) { this.ID = ID; }
public String GetBy() { return by; }
public void SetBy(String by) { this.by = by; }
public String GetRu() { return ru; }
public void SetRu(String ru) { this.ru = ru; }
public String GetUa() { return ua; }
public void SetUa(String ua) { this.ua = ua; }
public String GetEn() { return en; }
public void SetEn(String en) { this.by = en; }

}

By the way, everything is fine in the pom.xml file, all the necessary dependencies are registered:

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>3.1.2</version>
<relativePath/> 
</parent>
<groupId>com.Citatnik</groupId>
<artifactId>Citatnik</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>Citatnik</name>
<description>Citatnik project</description>
<properties>
<java.version>17</java.version>
</properties>

&lt;dependencies&gt;
&lt;dependency&gt;
&lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
&lt;artifactId&gt;spring-boot-starter-thymeleaf&lt;/artifactId&gt;
&lt;/dependency&gt;
&lt;dependency&gt;
&lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
&lt;artifactId&gt;spring-boot-starter-web&lt;/artifactId&gt;
&lt;/dependency&gt;
&lt;dependency&gt;
&lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
&lt;artifactId&gt;spring-boot-starter-data-jpa&lt;/artifactId&gt;
&lt;/dependency&gt;
&lt;dependency&gt;
&lt;groupId&gt;mysql&lt;/groupId&gt;
&lt;artifactId&gt;mysql-connector-java&lt;/artifactId&gt;
&lt;scope&gt;runtime&lt;/scope&gt;
&lt;version&gt;8.0.30&lt;/version&gt;
&lt;/dependency&gt;
&lt;dependency&gt;
&lt;groupId&gt;javax.persistence&lt;/groupId&gt;
&lt;artifactId&gt;javax.persistence-api&lt;/artifactId&gt;
&lt;version&gt;2.2&lt;/version&gt;
&lt;/dependency&gt;
&lt;dependency&gt;
&lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
&lt;artifactId&gt;spring-boot-devtools&lt;/artifactId&gt;
&lt;scope&gt;runtime&lt;/scope&gt;
&lt;optional&gt;true&lt;/optional&gt;
&lt;/dependency&gt;
&lt;dependency&gt;
&lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
&lt;artifactId&gt;spring-boot-starter-test&lt;/artifactId&gt;
&lt;scope&gt;test&lt;/scope&gt;
&lt;exclusions&gt;
&lt;exclusion&gt;
&lt;groupId&gt;org.junit.vintage&lt;/groupId&gt;
&lt;artifactId&gt;junit-vintage-engine&lt;/artifactId&gt;
&lt;/exclusion&gt;
&lt;/exclusions&gt;
&lt;/dependency&gt;
&lt;/dependencies&gt;
&lt;build&gt;
&lt;plugins&gt;
&lt;plugin&gt;
&lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
&lt;artifactId&gt;spring-boot-maven-plugin&lt;/artifactId&gt;
&lt;/plugin&gt;
&lt;/plugins&gt;
&lt;/build&gt;

</project>


Here is logging out from Spring application:

:: Spring Boot :: (v3.1.2)

2023-07-31T19:01:34.457+03:00 INFO 3336 --- [ restartedMain] c.Citatnik.Citatnik.CitatnikApplication : Starting CitatnikApplication using Java 17.0.6 with PID 3336 (C:\Users\dddry\OneDrive\Рабочий стол\Цитатник\Citatnik\target\classes started by dddry in C:\Users\dddry\OneDrive\Рабочий стол\Цитатник\Citatnik)
2023-07-31T19:01:34.461+03:00 INFO 3336 --- [ restartedMain] c.Citatnik.Citatnik.CitatnikApplication : No active profile set, falling back to 1 default profile: "default"
2023-07-31T19:01:34.539+03:00 INFO 3336 --- [ restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : Devtools property defaults active! Set 'spring.devtools.add-properties' to 'false' to disable
2023-07-31T19:01:34.539+03:00 INFO 3336 --- [ restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : For additional web related logging consider setting the 'logging.level.web' property to 'DEBUG'
2023-07-31T19:01:35.213+03:00 INFO 3336 --- [ restartedMain] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data JPA repositories in DEFAULT mode.
2023-07-31T19:01:35.232+03:00 INFO 3336 --- [ restartedMain] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 11 ms. Found 0 JPA repository interfaces.
2023-07-31T19:01:35.866+03:00 INFO 3336 --- [ restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2023-07-31T19:01:35.876+03:00 INFO 3336 --- [ restartedMain] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2023-07-31T19:01:35.876+03:00 INFO 3336 --- [ restartedMain] o.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/10.1.11]
2023-07-31T19:01:35.945+03:00 INFO 3336 --- [ restartedMain] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2023-07-31T19:01:35.946+03:00 INFO 3336 --- [ restartedMain] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 1405 ms
2023-07-31T19:01:36.094+03:00 INFO 3336 --- [ restartedMain] o.hibernate.jpa.internal.util.LogHelper : HHH000204: Processing PersistenceUnitInfo [name: default]
2023-07-31T19:01:36.148+03:00 INFO 3336 --- [ restartedMain] org.hibernate.Version : HHH000412: Hibernate ORM core version 6.2.6.Final
2023-07-31T19:01:36.149+03:00 INFO 3336 --- [ restartedMain] org.hibernate.cfg.Environment : HHH000406: Using bytecode reflection optimizer
2023-07-31T19:01:36.272+03:00 INFO 3336 --- [ restartedMain] o.h.b.i.BytecodeProviderInitiator : HHH000021: Bytecode provider name : bytebuddy
2023-07-31T19:01:36.396+03:00 INFO 3336 --- [ restartedMain] o.s.o.j.p.SpringPersistenceUnitInfo : No LoadTimeWeaver setup: ignoring JPA class transformer
2023-07-31T19:01:36.409+03:00 INFO 3336 --- [ restartedMain] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting...
2023-07-31T19:01:36.664+03:00 INFO 3336 --- [ restartedMain] com.zaxxer.hikari.pool.HikariPool : HikariPool-1 - Added connection com.mysql.cj.jdbc.ConnectionImpl@41c02a96
2023-07-31T19:01:36.666+03:00 INFO 3336 --- [ restartedMain] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed.
2023-07-31T19:01:36.824+03:00 INFO 3336 --- [ restartedMain] o.h.b.i.BytecodeProviderInitiator : HHH000021: Bytecode provider name : bytebuddy
2023-07-31T19:01:37.044+03:00 INFO 3336 --- [ restartedMain] o.h.e.t.j.p.i.JtaPlatformInitiator : HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
2023-07-31T19:01:37.048+03:00 INFO 3336 --- [ restartedMain] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default'
2023-07-31T19:01:37.094+03:00 WARN 3336 --- [ restartedMain] JpaBaseConfiguration$JpaWebConfiguration : spring.jpa.open-in-view is enabled by default. Therefore, database queries may be performed during view rendering. Explicitly configure spring.jpa.open-in-view to disable this warning
2023-07-31T19:01:37.542+03:00 INFO 3336 --- [ restartedMain] o.s.b.d.a.OptionalLiveReloadServer : LiveReload server is running on port 35729
2023-07-31T19:01:37.574+03:00 INFO 3336 --- [ restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2023-07-31T19:01:37.585+03:00 INFO 3336 --- [ restartedMain] c.Citatnik.Citatnik.CitatnikApplication : Started CitatnikApplication in 3.679 seconds (process running for 4.084)


I checked the port, database name, username and password - everything is correct. However, when I run the application and go to phpMyAdmin, I see a message that no tables were found in the database. What could be the issue here?
</details>
# 答案1
**得分**: 1
你正在使用spring-boot 3.1.2，这意味着你应该将你的
import javax.persistence.*;
替换为
import jakarta.persistence.*;
关于你的Maven依赖，你应该移除这个
<dependency>
<groupId>javax.persistence</groupId>
<artifactId>javax.persistence-api</artifactId>
<version>2.2</version>
</dependency>
因为你使用了
spring-boot-starter-data-jpa
它依赖于Hibernate。Hibernate然后依赖于jakarta.persistence API，使其类可用于你的应用程序代码。
关于你的问题，应用程序启动后你看不到表格。
只需尝试替换应用程序属性参数
spring.jpa.hibernate.ddl-auto=create
在首次运行应用程序后，将其替换为 `update`
<details>
<summary>英文:</summary>
Your are using spring-boot 3.1.2, it mean you should replace your 
import javax.persistence.*;
with
import jakarta.persistence.*;
About your maven dependency you should to remove this one
&lt;dependency&gt;
&lt;groupId&gt;javax.persistence&lt;/groupId&gt;
&lt;artifactId&gt;javax.persistence-api&lt;/artifactId&gt;
&lt;version&gt;2.2&lt;/version&gt;
&lt;/dependency&gt;
because you use 
spring-boot-starter-data-jpa
it has dependencies on Hibernate. Hibernate then has a dependency on the jakarta.persistence API which makes its classes available to your application&#39;s code.
About your problem, you don&#39;t see the tables after application start. 
Just try to replace an application properties param 
spring.jpa.hibernate.ddl-auto=create
And after first run of application 
replace with `update`
</details>

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