如果我們像給任務配置監聽，按照常規的做法是這樣的

一個個配置，比較麻煩。

現在利用ActivitiEventListener，監聽全局事件，並且可以判斷不同的事件類型，進而執行不同的業務邏輯。

1.定義事件處理handler介面

用介面來定義統一約定

public interface EventHandler {
    void handle(ActivitiEvent event);
}

2.實現不同事件

任務結束事件

 */
public class TaskCompleteListener implements EventHandler {

    protected Logger logger = LoggerFactory.getLogger(getClass());
    @Override
    public void handle(ActivitiEvent event) {
        ActivitiEntityEventImpl eventImpl = (ActivitiEntityEventImpl) event;
        TaskEntity taskEntity = (TaskEntity) eventImpl.getEntity();
   

    }
}

任務創建事件

public class TaskCreateListener implements EventHandler {

    protected Logger logger = LoggerFactory.getLogger(getClass());

    @Override
    public void handle(ActivitiEvent event) {
        ActivitiEntityEventImpl eventImpl = (ActivitiEntityEventImpl) event;
        TaskEntity taskEntity = (TaskEntity) eventImpl.getEntity();
        
    }

}

還有很多事件，比如TASK_ASSIGNED，PROCESS_STARTED，PROCESS_COMPLETED

3.實現ActivitiEventListener

public class GlobalEventListener implements ActivitiEventListener {
    protected Logger logger = LoggerFactory.getLogger(getClass());
    /**
     * 各類 Event 的處理器
     */
    private Map<ActivitiEventType, EventHandler> handlers = new HashMap<ActivitiEventType, EventHandler>();



    @Override
    public void onEvent(ActivitiEvent event) {
        EventHandler eventHandler = handlers.get(event.getType());
        if(eventHandler!=null){
            eventHandler.handle(event);
        }
    }

    @Override
    public boolean isFailOnException() {
        return false;
    }

    public Map<ActivitiEventType, EventHandler> getHandlers() {
        return handlers;
    }

    public void setHandlers(Map<ActivitiEventType, EventHandler> handlers) {
        this.handlers = handlers;
    }
}

4.註冊事件監聽

 <bean id="processEngineConfiguration" class="org.activiti.spring.SpringProcessEngineConfiguration">
        <property name="dataSource" ref="dataSource"/>
        <property name="transactionManager" ref="transactionManager"/>
        <property name="databaseSchemaUpdate" value="true"/>
        <property name="jobExecutorActivate" value="false"/>
        <property name="history" value="full"/>
        <property name="processDefinitionCacheLimit" value="10"/>

        <!-- 生成流程圖的字體 -->
        <property name="activityFontName" value="宋體"/>
        <property name="labelFontName" value="宋體"/>
        <property name="annotationFontName" value="宋體"/>
        <!-- 自動部署 -->
        <property name="deploymentResources">
            <list>
                <value>classpath*:*</value>
            </list>
        </property>
        <!--  <property name="idGenerator" ref="idGenerator"/>-->
        <property name="eventListeners">
            <list>
                  <ref bean="globalEventListener"/>
            </list>
        </property>
        <property name="customFormTypes">
            <bean class="org.activiti.engine.impl.form.DateFormType">
                <constructor-arg value="yyyy-MM-dd HH:mm:ss"/>
            </bean>
        </property>
    </bean>

    <bean id="processEngine" class="org.activiti.spring.ProcessEngineFactoryBean">
        <property name="processEngineConfiguration" ref="processEngineConfiguration"/>
    </bean>

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

    <!--流程全局事件處理器-->
    <bean id="globalEventListener" class="GlobalEventListener">
         <property name="handlers">
             <map>
                 <entry key="TASK_CREATED">
                     <bean class="TaskCreateListener"/>
                 </entry>
                   <entry key="TASK_COMPLETED">
                     <bean class="TaskCompleteListener"/>
                   </entry>
             </map>
         </property>
     </bean>

優點

• 這樣代碼清晰，業務邏輯解耦，單一職責
• 省去在bpmn.xml中配置，方便。