1，bug展示

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'processEngine': FactoryBean threw exception on object creation; nested exception is org.flowable.common.engine.api.FlowableWrongDbException: version mismatch: library version is '6.6.0.0', db version is 5.99.0.0 Hint: Set <property name="databaseSchemaUpdate" to value="true" or value="create-drop" (use create-drop for testing only!) in bean processEngineConfiguration in flowable.cfg.xml for automatic schema creation
  at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:176) ~[spring-beans-5.2.12.RELEASE.jar:5.2.12.RELEASE]
  at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.getObjectFromFactoryBean(FactoryBeanRegistrySupport.java:101) ~[spring-beans-5.2.12.RELEASE.jar:5.2.12.RELEASE]
  at org.springframework.beans.factory.support.AbstractBeanFactory.getObjectForBeanInstance(AbstractBeanFactory.java:1828) ~[spring-beans-5.2.12.RELEASE.jar:5.2.12.RELEASE]
  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getObjectForBeanInstance(AbstractAutowireCapableBeanFactory.java:1265) ~[spring-beans-5.2.12.RELEASE.jar:5.2.12.RELEASE]
  at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:261) ~[spring-beans-5.2.12.RELEASE.jar:5.2.12.RELEASE]
  at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-5.2.12.RELEASE.jar:5.2.12.RELEASE]
  at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276) ~[spring-beans-5.2.12.RELEASE.jar:5.2.12.RELEASE]
  at org.springframework.beans.factory.support.DefaultListableBeanFactory.addCandidateEntry(DefaultListableBeanFactory.java:1532) ~[spring-beans-5.2.12.RELEASE.jar:5.2.12.RELEASE]
  at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1489) ~[spring-beans-5.2.12.RELEASE.jar:5.2.12.RELEASE]
  at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1270) ~[spring-beans-5.2.12.RELEASE.jar:5.2.12.RELEASE]
  at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1227) ~[spring-beans-5.2.12.RELEASE.jar:5.2.12.RELEASE]
  at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:886) ~[spring-beans-5.2.12.RELEASE.jar:5.2.12.RELEASE]
  at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:790) ~[spring-beans-5.2.12.RELEASE.jar:5.2.12.RELEASE]
  ... 25 common frames omitted

2，解决方案

https://blog.csdn.net/lovemy016/article/details/120085600?spm=1001.2101.3001.6650.3&utm_medium=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7ERate-3.pc_relevant_default&depth_1-utm_source=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7ERate-3.pc_relevant_default

3，我的实践

3.1 根据博主的情况，第一个是检查 act_ge_property 表里面的version是否一致，如图，版本数据查看正确

3.2 数据库是否设置了忽略大小写

命令行检查，如图，确实是忽略大小写

mysql忽略大小写设置操作路径：https://www.cnblogs.com/breakingbrad/p/12417380.html

但是完成上面两步骤之后，启动项目依旧报错，于是开始下面的步骤

3.3 删除所有的act_前缀表，重新执行sql导入表，再启动项目，依旧报错

 version mismatch: library version is '6.6.0.0', db version is 5.99.0.0 
 

3.4 仔细看了一下执行的sql，发现有部分sql执行失败，原因是因为原本的旧表未删除成功，以flw_为前缀的表未删除

最后，删除act_前缀表和flw_为前缀的表之后，执行插入表的sql（确保sql全部执行成功），启动项目即可；