流程图 - SpringBoot 集成 Activiti 新增 serviceTask报错

流程图 - SpringBoot 集成 Activiti 新增 serviceTask 配置服务类 启动报错，求大神们指点，详情如下：

 

2021-01-04 14:06:53.027 ERROR 10108 --- [           main] o.a.e.impl.interceptor.CommandContext    : Error while closing command context

org.activiti.engine.ActivitiException: Errors while parsing:
[Validation set: 'activiti-executable-process' | Problem: 'activiti-servicetask-missing-implementation'] : One of the attributes 'class', 'delegateExpression', 'type', 'operation', or 'expression' is mandatory on serviceTask. - [Extra info : processDefinitionId = Process_1jmpcne | id = Activity_1467ect |  | activityName = 环节3 | ] ( line: 50, column: 106)

	at org.activiti.engine.impl.bpmn.parser.BpmnParse.execute(BpmnParse.java:216) ~[activiti-engine-5.22.0.jar:5.22.0]
	at org.activiti.engine.impl.bpmn.deployer.BpmnDeployer.deploy(BpmnDeployer.java:136) ~[activiti-engine-5.22.0.jar:5.22.0]
	at org.activiti.engine.impl.persistence.deploy.DeploymentManager.deploy(DeploymentManager.java:58) ~[activiti-engine-5.22.0.jar:5.22.0]
	at org.activiti.engine.impl.cmd.DeployCmd.execute(DeployCmd.java:106) ~[activiti-engine-5.22.0.jar:5.22.0]
	at org.activiti.engine.impl.cmd.DeployCmd.execute(DeployCmd.java:37) ~[activiti-engine-5.22.0.jar:5.22.0]
	at org.activiti.engine.impl.interceptor.CommandInvoker.execute(CommandInvoker.java:24) ~[activiti-engine-5.22.0.jar:5.22.0]
	at org.activiti.engine.impl.interceptor.CommandContextInterceptor.execute(CommandContextInterceptor.java:57) ~[activiti-engine-5.22.0.jar:5.22.0]
	at org.activiti.spring.SpringTransactionInterceptor$1.doInTransaction(SpringTransactionInterceptor.java:47) [activiti-spring-5.22.0.jar:5.22.0]
	at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:133) [spring-tx-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.activiti.spring.SpringTransactionInterceptor.execute(SpringTransactionInterceptor.java:45) [activiti-spring-5.22.0.jar:5.22.0]
	at org.activiti.engine.impl.interceptor.LogInterceptor.execute(LogInterceptor.java:31) [activiti-engine-5.22.0.jar:5.22.0]
	at org.activiti.engine.impl.cfg.CommandExecutorImpl.execute(CommandExecutorImpl.java:40) [activiti-engine-5.22.0.jar:5.22.0]
	at org.activiti.engine.impl.cfg.CommandExecutorImpl.execute(CommandExecutorImpl.java:35) [activiti-engine-5.22.0.jar:5.22.0]
	at org.activiti.engine.impl.RepositoryServiceImpl.deploy(RepositoryServiceImpl.java:79) [activiti-engine-5.22.0.jar:5.22.0]
	at org.activiti.engine.impl.repository.DeploymentBuilderImpl.deploy(DeploymentBuilderImpl.java:156) [activiti-engine-5.22.0.jar:5.22.0]
	at org.activiti.spring.autodeployment.DefaultAutoDeploymentStrategy.deployResources(DefaultAutoDeploymentStrategy.java:64) [activiti-spring-5.22.0.jar:5.22.0]
	at org.activiti.spring.SpringProcessEngineConfiguration.autoDeployResources(SpringProcessEngineConfiguration.java:111) [activiti-spring-5.22.0.jar:5.22.0]
	at org.activiti.spring.SpringProcessEngineConfiguration.buildProcessEngine(SpringProcessEngineConfiguration.java:67) [activiti-spring-5.22.0.jar:5.22.0]
	at org.activiti.spring.ProcessEngineFactoryBean.getObject(ProcessEngineFactoryBean.java:60) [activiti-spring-5.22.0.jar:5.22.0]
	at org.activiti.spring.ProcessEngineFactoryBean.getObject(ProcessEngineFactoryBean.java:32) [activiti-spring-5.22.0.jar:5.22.0]
	at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:168) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.getObjectFromFactoryBean(FactoryBeanRegistrySupport.java:103) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getObjectForBeanInstance(AbstractBeanFactory.java:1634) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:317) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:835) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:741) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:467) [spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE]
	at org.springframework.beans.factory.su