工作流引擎Activiti集成JPA持久化保存流程数据

2021-04-28  本文已影响0人  攻城狮Chova

Activiti中JPA简介

JPA实体要求

JPA配置

<bean id="processEngineConfiguration" class="org.activiti.engine.impl.cfg.StandaloneInMemProcessEngineConfiguration">

    <!-- 数据库的配置 -->
    <property name="databaseSchemaUpdate" value="true" />
    <property name="jdbcUrl" value="jdbc:h2:mem:JpaVariableTest;DB_CLOSE_DELAY=1000" />

    <property name="jpaPersistenceUnitName" value="activiti-jpa-pu" />
    <property name="jpaHandleTransaction" value="true" />
    <property name="jpaCloseEntityManager" value="true" />

    <!-- job executor configurations -->
    <property name="jobExecutorActivate" value="false" />

    <!-- mail server configurations -->
    <property name="mailServerPort" value="5025" />
</bean>

<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
  <property name="persistenceUnitManager" ref="pum"/>
  <property name="jpaVendorAdapter">
    <bean class="org.springframework.orm.jpa.vendor.OpenJpaVendorAdapter">
      <property name="databasePlatform" value="org.apache.openjpa.jdbc.sql.H2Dictionary" />
    </bean>
  </property>
</bean>

<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="jpaEntityManagerFactory" ref="entityManagerFactory" />
  <property name="jpaHandleTransaction" value="true" />
  <property name="jpaCloseEntityManager" value="true" />
  <property name="jobExecutorActivate" value="false" />
</bean>

ProcessEngine processEngine = ProcessEngineConfiguration
  .createProcessEngineConfigurationFromResourceDefault()
  .setJpaPersistenceUnitName("activiti-pu")
  .buildProcessEngine();

配置的属性有:

JPA用法

简单示例

@Entity(name = "JPA_ENTITY_FIELD")
public class FieldAccessJPAEntity {

  @Id
  @Column(name = "ID_")
  private Long id;

  private String value;

  public FieldAccessJPAEntity() {
    // Empty constructor needed for JPA
  }

  public Long getId() {
    return id;
  }

  public void setId(Long id) {
    this.id = id;
  }

  public String getValue() {
    return value;
  }

  public void setValue(String value) {
    this.value = value;
  }
}

Map<String, Object> variables = new HashMap<String, Object>();
variables.put("entityToUpdate", entityToUpdate);

ProcessInstance processInstance = runtimeService.startProcessInstanceByKey("UpdateJPAValuesProcess", variables);

<serviceTask id='theTask' name='updateJPAEntityTask' activiti:expression="${entityToUpdate.setValue('updatedValue')}" />

// Servicetask in process 'UpdateJPAValuesProcess' should have set value on entityToUpdate.
Object updatedEntity = runtimeService.getVariable(processInstance.getId(), "entityToUpdate");
assertTrue(updatedEntity instanceof FieldAccessJPAEntity);
assertEquals("updatedValue", ((FieldAccessJPAEntity)updatedEntity).getValue())

查询JPA流程变量

ProcessInstance result = runtimeService.createProcessInstanceQuery().variableValueEquals("entityToQuery", entityToQuery).singleResult();

使用Spring beans和JPA结合的高级例子

<?xml version="1.0" encoding="UTF-8"?>
<definitions id="taskAssigneeExample"
  xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:activiti="http://activiti.org/bpmn"
  targetNamespace="org.activiti.examples">

  <process id="LoanRequestProcess" name="Process creating and handling loan request">
    <startEvent id='theStart' />
    <sequenceFlow id='flow1' sourceRef='theStart' targetRef='createLoanRequest' />

    <serviceTask id='createLoanRequest' name='Create loan request'
      activiti:expression="${loanRequestBean.newLoanRequest(customerName, amount)}"
      activiti:resultVariable="loanRequest"/>
    <sequenceFlow id='flow2' sourceRef='createLoanRequest' targetRef='approveTask' />

    <userTask id="approveTask" name="Approve request" />
    <sequenceFlow id='flow3' sourceRef='approveTask' targetRef='approveOrDissaprove' />

    <serviceTask id='approveOrDissaprove' name='Store decision'
      activiti:expression="${loanRequest.setApproved(approvedByManager)}" />
    <sequenceFlow id='flow4' sourceRef='approveOrDissaprove' targetRef='exclusiveGw' />

    <exclusiveGateway id="exclusiveGw" name="Exclusive Gateway approval" />
    <sequenceFlow id="endFlow1" sourceRef="exclusiveGw" targetRef="theEnd">
      <conditionExpression xsi:type="tFormalExpression">${loanRequest.approved}</conditionExpression>
    </sequenceFlow>
    <sequenceFlow id="endFlow2" sourceRef="exclusiveGw" targetRef="sendRejectionLetter">
      <conditionExpression xsi:type="tFormalExpression">${!loanRequest.approved}</conditionExpression>
    </sequenceFlow>

    <userTask id="sendRejectionLetter" name="Send rejection letter" />
    <sequenceFlow id='flow5' sourceRef='sendRejectionLetter' targetRef='theOtherEnd' />

    <endEvent id='theEnd' />
    <endEvent id='theOtherEnd' />
  </process>

</definitions>

上面的例子展示了JPA结合Spring和参数化方法表达式的强大优势 :所有的流程就不需要自定义java代码(Spring bean除外),大幅度的加快了流程部署

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