因我的项目需要，将cloud我的项目的工作流模块迁徙到springboot我的项目中。将中途遇到的一些问题整合到此处。
已解决局部
activiti依赖spring与我的项目spring不兼容。
解决
<dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>${spring-boot-starter.version}</version> <scope>import</scope> <type>pom</type> </dependency> </dependencies></dependencyManagement>MyBatis依赖抵触
启动报错：
***************************APPLICATION FAILED TO START***************************Description:An attempt was made to call a method that does not exist. The attempt was made from the following location: org.mybatis.spring.SqlSessionFactoryBean.buildSqlSessionFactory(SqlSessionFactoryBean.java:564)The following method did not exist: org.apache.ibatis.session.Configuration.setDefaultEnumTypeHandler(Ljava/lang/Class;)VThe method's class, org.apache.ibatis.session.Configuration, is available from the following locations: jar:file:/D:/Program%20Files/maven/.m2/repository/org/mybatis/mybatis/3.4.2/mybatis-3.4.2.jar!/org/apache/ibatis/session/Configuration.classIt was loaded from the following location: file:/D:/Program%20Files/maven/.m2/repository/org/mybatis/mybatis/3.4.2/mybatis-3.4.2.jarAction:Correct the classpath of your application so that it contains a single, compatible version of org.apache.ibatis.session.ConfigurationDisconnected from the target VM, address: '127.0.0.1:64349', transport: 'socket'Process finished with exit code 1解决
引入activiti时排除MyBatis
<dependency> <groupId>org.activiti</groupId> <artifactId>activiti-spring-boot-starter</artifactId> <exclusions> <exclusion> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> </exclusion> </exclusions></dependency>activiti 的bean与我的项目中的bean重名。
注：已配置 spring.main.allow-bean-definition-overriding: true 容许我的项目存在重名bean。通过注解创立的bean默认应用org.springframework.context.annotation.AnnotationBeanNameGenerator#generateBeanName生成beanName。如果没有指定名字，则默认应用首字母小写的类名或者办法名。
通过beanFactory将activiti的TaskService、HistoryService等服务注入spring容器中。我的项目自身也有同名的service时，同名的只有一个service被创立。
// activiti Service创立： @Bean public ProcessEngineConfiguration processEngineConfiguration(DataSource dataSource, PlatformTransactionManager transactionManager) { SpringProcessEngineConfiguration processEngineConfiguration = new SpringProcessEngineConfiguration(); processEngineConfiguration.setDataSource(dataSource); processEngineConfiguration.setDatabaseType("mysql"); processEngineConfiguration.setTransactionManager(transactionManager); return processEngineConfiguration; } /** * 流程引擎，与spring整合应用factoryBean */ @Bean public ProcessEngineFactoryBean processEngine(ProcessEngineConfiguration processEngineConfiguration) { ProcessEngineFactoryBean processEngineFactoryBean = new ProcessEngineFactoryBean(); processEngineFactoryBean.setProcessEngineConfiguration((ProcessEngineConfigurationImpl) processEngineConfiguration); return processEngineFactoryBean; } @Bean public RepositoryService repositoryService(ProcessEngine processEngine) { return processEngine.getRepositoryService(); } @Bean public RuntimeService runtimeService(ProcessEngine processEngine) { return processEngine.getRuntimeService(); } @Bean public TaskService taskService(ProcessEngine processEngine) { return processEngine.getTaskService(); } @Bean public HistoryService historyService(ProcessEngine processEngine) { return processEngine.getHistoryService(); }问题排查
spring默认的重名解决办法为org.springframework.beans.factory.support.DefaultListableBeanFactory#registerBeanDefinition，间接笼罩先前的bean。
监控 org.springframework.context.annotation.ClassPathBeanDefinitionScanner#doScan
发现,通过ComponentScan扫描的bean最先被创立，而所以导致通过@Service创立的bean被笼罩，@Autowrite无奈注入。尽管能够通过批改类名或者指定bean名称解决，然而闲着也是闲着，不如折腾一下。
既然因为重名导致被笼罩，又不想手动改名字，那就批改生成beanName的规定。
继承AnnotationBeanNameGenerator 重写generateBeanName办法,应用类的残缺门路作为bean名称。
我的项目应用springboot2.2.13 须要通过@ComponentScan( basePackages = {"xxx"},nameGenerator = UniqueNameGenerator.class)配置失效。
此处又有几个小知识点：@SpringBootApplication默认扫描同级目录下的包。@ComponentScan会笼罩@SpringBootApplication中配置的门路，而@ComponentScans不会。先前画龙点睛应用了@ComponentScans，程序会把两种扫包规定都执行一遍，而@ComponentScans应用的是自定义的命名规定@SpringBootApplication应用的是默认的命名规定，导致局部包下的bean会被创立两遍。
报错：
implementations of CachingConfigurer were found when only 1 was expected. Refactor the configuration such that CachingConfigurer is implemented only once or not at all.解决
应用自定义beanName生成规定，并通过ComponentScan配置
public class UniqueNameGenerator extends AnnotationBeanNameGenerator { @Override @NonNull public String generateBeanName(@NonNull BeanDefinition definition,@NonNull BeanDefinitionRegistry registry) { if (definition instanceof AnnotatedBeanDefinition) { //获取指定beanName String beanName = determineBeanNameFromAnnotation((AnnotatedBeanDefinition) definition); if (StringUtils.hasText(beanName)) { return beanName; } } return Objects.requireNonNull(definition.getBeanClassName()); }}@ComponentScan(basePackages = {"com.xxx", "org.activiti.engine.impl"}, nameGenerator = UniqueNameGenerator.class)@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})public class Application{调用接口报错，两个类加载器中有两个不同的对象
Handler dispatch failed; nested exception is java.lang.LinkageError: loader constraint violation: when resolving interface method \"org.activiti.engine.RepositoryService.createModelQuery()Lorg/activiti/engine/repository/ModelQuery;\" the class loader (instance of org/springframework/boot/devtools/restart/classloader/RestartClassLoader) of the current class, com/pms/workflow/service/ModelService, and the class loader (instance of sun/misc/Launcher$AppClassLoader) for the method's defining class, org/activiti/engine/RepositoryService, have different Class objects for the type org/activiti/engine/repository/ModelQuery used in the signature谬误内容粗心是：调用RepositoryService.createModelQuery()Lorg时发现两个类加载器RestartClassLoader和AppClassLoader中存在不同的class对象
AppClassLoader是JVM的利用类加载器，RestartClassLoader 是个啥？
点进去一看门路org.springframework.boot.devtools.restart.classloader.RestartClassLoader，
程度无限搞不懂问题的本源，删掉spring-boot-devtools依赖就完事。
未解决局部
Spring
springboot多模块我的项目,新建的子模块内容无奈引入
预计是IDE问题，删除后新建就好了
参考
《聊Spring的bean笼罩（存在同名name/id问题），介绍Spring名称生成策略接口BeanNameGenerator》
《SprintBoot devtools导致同一个类呈现两个不同的Class类》