Spring Boot集成MySQL8.0.32启动报错：Hibernate方言类无法加载

问题描述 #

在Eclipse中将MySQL8.0.32连接到Spring Boot项目，运行主类时出现报错，错误指向application.properties中的方言配置项，无法加载指定的Hibernate方言类，最终导致entityManagerFactory Bean创建失败。

配置文件信息 #

application.properties #

spring.datasource.url=jdbc:mysql://localhost:3306/emp?useSSL=false
spring.datasource.username=root
spring.datasource.password=root
#hibernate properties 
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBdialect
#create,create-drop
spring.hibernate.ddl-auto=update

主类代码 #

StringProject1Application.java #

package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class StringProject1Application {

      public static void main(String[] args) {
      SpringApplication.run(StringProject1Application.class, args);
      }

}

报错信息 #

org.hibernate.boot.registry.selector.spi.StrategySelectionException: Unable to resolve name [org.hibernate.dialect.MySQL5InnoDBdialect] as strategy [org.hibernate.dialect.Dialect]
    at org.hibernate.boot.registry.selector
Caused by: org.hibernate.boot.registry.classloading.spi.ClassLoadingException: Unable to load class [org.hibernate.dialect.MySQL5InnoDBdialect]
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:123) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.boot.registry.selector.internal.StrategySelectorImpl.selectStrategyImplementor(StrategySelectorImpl.java:151) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    ... 39 common frames omitted
Caused by: java.lang.ClassNotFoundException: Could not load requested class : org.hibernate.dialect.MySQL5InnoDBdialect
    at org.hibernate.boot.registry.classloading.internal.AggregatedClassLoader.findClass(AggregatedClassLoader.java:210) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:587) ~[na:na]
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:520) ~[na:na]
    at java.base/java.lang.Class.forName0(Native Method) ~[na:na]
    at java.base/java.lang.Class.forName(Class.java:467) ~[na:na]
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:120) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    ... 40 common frames omitted
org.springframework.beans.factory.BeanCreationException: Error creating bean with name   'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1751) ~[spring-beans-6.0.4.jar:6.0.4]
    at org.springframework.beans.factory.
Caused by: org.hibernate.service.spi.ServiceException: Unable to create requested service   [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment]
    at   org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:267) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at   org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:230) ~[hibernate-core-6.1.6.Final.jar:6.1.6.Final]
    at org.hibernate.service.

解决步骤 #

1. 修正方言类名与适配MySQL8.0
   原配置中的org.hibernate.dialect.MySQL5InnoDBdialect存在两个问题：一是类名拼写错误（dialect首字母需大写为Dialect，正确类名为org.hibernate.dialect.MySQL5InnoDBDialect）；二是该方言适配MySQL5.x版本，与你使用的MySQL8.0不匹配。建议替换为MySQL8.0对应的方言：

   spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL8Dialect
   

2. 修正ddl-auto配置项前缀
   Spring Boot中JPA的DDL配置项前缀应为spring.jpa.hibernate，而非spring.hibernate，修改后：

   spring.jpa.hibernate.ddl-auto=update
   

3. 可选：添加时区配置
   MySQL8.0默认要求时区配置，可在数据源URL中添加时区参数避免潜在报错：

   spring.datasource.url=jdbc:mysql://localhost:3306/emp?useSSL=false&serverTimezone=Asia/Shanghai
   

修改后的完整application.properties示例：

spring.datasource.url=jdbc:mysql://localhost:3306/emp?useSSL=false&serverTimezone=Asia/Shanghai
spring.datasource.username=root
spring.datasource.password=root
#hibernate properties 
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL8Dialect
#create,create-drop
spring.jpa.hibernate.ddl-auto=update

内容的提问来源于stack exchange，提问作者Sireesha jinkala