Spring boot 集成工作流flowable去掉xml配置

工作流Flowable和Spring集成时，有一个xml是用来配置ProcessEngine的信息，xml的内容如下所示：

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:context="http://www.springframework.org/schema/context" xmlns:jdbc="http://www.springframework.org/schema/jdbc"
xmlns:jee="http://www.springframework.org/schema/jee" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:jpa="http://www.springframework.org/schema/data/jpa"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/aop  http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/beans    http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context     http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc.xsd http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa.xsd"> 
<!-- Activiti begin -->
<bean id="processEngineConfiguration" class="com.xxx.xxx.config.ExtProcessEngineConfiguration">
<property name="dataSource" ref="dataSource" />
<property name="transactionManager" ref="transactionManager" />
<property name="databaseSchemaUpdate" value="true" />
<!--  property name="jobExecutorActivate" value="false" /-->
<property name="customSessionFactories">
<list>
<bean class="com.xxx.xxx.entity.EntityManagerFactory">
<constructor-arg index="0" value="org.flowable.idm.engine.impl.persistence.entity.UserEntityManager" />
<constructor-arg index="1">
<bean class="com.xxx.xxx.entity.SmartUserEntityManager"/>
</constructor-arg>
</bean>
<bean class="com.xxx.xxx.entity.EntityManagerFactory">
<constructor-arg index="0" value="org.flowable.idm.engine.impl.persistence.entity.GroupEntityManager" />
<constructor-arg index="1">
<bean class="com.xxx.xxx.entity.SmartGroupEntityManager"/>
</constructor-arg>
</bean>
<bean class="com.xxx.xxx.entity.EntityManagerFactory">
<constructor-arg index="0" value="org.flowable.idm.engine.impl.persistence.entity.MembershipEntityManager" />
<constructor-arg index="1">
<bean class="com.xxx.xxx.entity.SmartMembershipEntityManager"/>
</constructor-arg>
</bean>
</list>
</property>

</bean>

<bean id="processEngine" factory-bean="processEngineConfiguration" factory-method="buildProcessEngine" />

<bean id="repositoryService" factory-bean="processEngineConfiguration" factory-method="getRepositoryService"  />
<bean id="runtimeService" factory-bean="processEngineConfiguration" factory-method="getRuntimeService" />
<bean id="taskService" factory-bean="processEngineConfiguration" factory-method="getTaskService" />
<bean id="historyService" factory-bean="processEngineConfiguration" factory-method="getHistoryService" />
<bean id="managementService" factory-bean="processEngineConfiguration" factory-method="getManagementService" />
<bean id="formService" factory-bean="processEngineConfiguration" factory-method="getFormService" />
<bean id="identityService" factory-bean="processEngineConfiguration" factory-method="getIdentityService" />

<bean id="commandExecutor" factory-bean="processEngineConfiguration" factory-method="getCommandExecutor" />
<bean id="processDefinitionCache" factory-bean="processEngineConfiguration" factory-method="getProcessDefinitionCache"/>

</beans>

使用Spring boot之后推崇java配置取代xml配置，要对这个xml进行改造首先得搞清楚这个xml里面的内容，主要是定义了ExtProcessEngineConfiguration和它相关的属性，

说明：

constructor-arg：通过构造函数注入。

property：通过setter对应的方法注入。

factory-method：通过工厂方法来构造java Bean

创建config配置文件WorkflowConfiguration，在这个类中通过@bean的注解构造ExtProcessEngineConfiguration 类，同时设置ExtProcessEngineConfiguration 需要的几个属性

@Configuration
public class WorkflowConfiguration {

private final DataSource dataSource;
private final PlatformTransactionManager transactionManager;

public WorkflowConfiguration(DataSource dataSource,PlatformTransactionManager transactionManager){
this.dataSource = dataSource;
this.transactionManager = transactionManager;
}

@Bean
public SmartUserEntityManager smartUserEntityManager() {
return new SmartUserEntityManager(new ExtProcessEngineConfiguration());
}

@Bean
public SmartGroupEntityManager smartGroupEntityManager() {
return new SmartGroupEntityManager(new ExtProcessEngineConfiguration());
}

@Bean
public SmartMembershipEntityManager smartMembershipEntityManager() {
return new SmartMembershipEntityManager(new ExtProcessEngineConfiguration());
}

public EntityManagerFactory userEntityManagerFactory(){
EntityManagerFactory entityManagerFactory = new EntityManagerFactory(UserEntityManager.class, smartUserEntityManager());
return entityManagerFactory;
}

public EntityManagerFactory groupEntityManagerFactory(){
EntityManagerFactory entityManagerFactory = new EntityManagerFactory(GroupEntityManager.class, smartGroupEntityManager());
return entityManagerFactory;
}

public EntityManagerFactory membershipEntityManagerFactory(){
EntityManagerFactory entityManagerFactory = new EntityManagerFactory(MembershipEntityManager.class, smartMembershipEntityManager());
return entityManagerFactory;
}

@Bean
public ExtProcessEngineConfiguration engineConfiguration(){
ExtProcessEngineConfiguration engineConfiguration = new ExtProcessEngineConfiguration();
engineConfiguration.setDatabaseSchemaUpdate("true");
engineConfiguration.setDataSource(dataSource);
engineConfiguration.setTransactionManager(transactionManager);

List<SessionFactory> customSessionFactories = new ArrayList<>();
customSessionFactories.add(userEntityManagerFactory());
customSessionFactories.add(groupEntityManagerFactory());
customSessionFactories.add(membershipEntityManagerFactory());
engineConfiguration.setCustomSessionFactories(customSessionFactories);

return engineConfiguration;

}

}

其中核心的代码是：

@Bean
public ExtProcessEngineConfiguration engineConfiguration()

这个方法。

其中有一个重点需要注意的地方是，在xml里面有一段：

<bean id="processEngine" factory-bean="processEngineConfiguration" factory-method="buildProcessEngine" />

这个是Spring使用实例工厂方法实例化Bean的一种方式，工作作流引擎Flowable的各个组件就是使用此方式实例化的。由于使用工厂实例化的Bean跟普通Bean不同，其返回的对象不是指定类的一个实例，其返回的是该FactoryBean的getObject方法所返回的对象。因此我们需要使用Spring Boot的方式来实例化Flowable的组件。有两种解决方法：

自定义FactoryBean，实现FactoryBean中的getObject这个方法，返回ProcessEngine对象

使用ProcessEngineFactoryBean，推荐使用这种方式，以下为ProcessEngineFactoryBean源码。

public class ProcessEngineFactoryBean implements FactoryBean<ProcessEngine> ..{
...
protected ProcessEngineImpl processEngine;

public ProcessEngine getObject() throws Exception {
initializeExpressionManager();
initializeTransactionExternallyManaged();

if (processEngineConfiguration.getBeans()==null) {
processEngineConfiguration.setBeans(new SpringBeanFactoryProxyMap(applicationContext));
}

processEngine = (ProcessEngineImpl) processEngineConfiguration.buildProcessEngine();

return processEngine;
}

...
}

ProcessEngineFactoryBean最终返回的是processEngine对象，repositoryService、runtimeService、formService等等组件都是通过processEngine里的getXX方法获得的。

通过WorkflowConfiguration就可以取代xml配置文件了。

在我们需要继承flowable-restApi的时候发现需要进行权限校验，我们可以通过下面的注解去掉security权限校验，在启动类上加上下面的注解：

@SpringBootApplication(exclude = {
org.springframework.boot.autoconfigure.security.SecurityAutoConfiguration.class,
org.flowable.spring.boot.SecurityAutoConfiguration.class})