camunda_04_quickstart

目標

設計和部署第一個簡單流程
使用Java實現流程處理
完成流程啟動測試

設計第一個流程

建模注意事項

模型文件和部署名其實并不重要,最重要是流程的Id, ProcessEngine是按照這個Id管理流程.
流程要設定為 Executable.

步驟

使用Model新建一個 camunda 7的模型文件, 命名為payment.bpm , 流程Id 設定為payment-retrieval , 并完成部署.
在流程中增加一個Service task, 類型選External,Topic設定為charge-card
BPMN xml 代碼

<?xml version="1.0" encoding="UTF-8"?>
<bpmn:definitions xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" xmlns:camunda="http://camunda.org/schema/1.0/bpmn" xmlns:di="http://www.omg.org/spec/DD/20100524/DI" xmlns:modeler="http://camunda.org/schema/modeler/1.0" id="Definitions_1xvrd7w" targetNamespace="http://bpmn.io/schema/bpmn" exporter="Camunda Modeler" exporterVersion="5.2.0" modeler:executionPlatform="Camunda Platform" modeler:executionPlatformVersion="7.17.0">
  <bpmn:process id="payment-retrieval" name="付款流程" isExecutable="true">
    <bpmn:startEvent id="StartEvent_1" name="付款請求">
      <bpmn:outgoing>Flow_0mcdkpl</bpmn:outgoing>
    </bpmn:startEvent>
    <bpmn:sequenceFlow id="Flow_0mcdkpl" sourceRef="StartEvent_1" targetRef="Activity_Charge" />
    <bpmn:serviceTask id="Activity_Charge" name="刷卡付款" camunda:type="external" camunda:topic="charge-card">
      <bpmn:incoming>Flow_0mcdkpl</bpmn:incoming>
      <bpmn:outgoing>Flow_16yugnw</bpmn:outgoing>
    </bpmn:serviceTask>
    <bpmn:endEvent id="EndEvent_1" name="付款完成">
      <bpmn:incoming>Flow_16yugnw</bpmn:incoming>
    </bpmn:endEvent>
    <bpmn:sequenceFlow id="Flow_16yugnw" sourceRef="Activity_Charge" targetRef="EndEvent_1" />
  </bpmn:process>
  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="payment-retrieval">
      <bpmndi:BPMNEdge id="Flow_0mcdkpl_di" bpmnElement="Flow_0mcdkpl">
        <di:waypoint x="215" y="117" />
        <di:waypoint x="270" y="117" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_16yugnw_di" bpmnElement="Flow_16yugnw">
        <di:waypoint x="370" y="117" />
        <di:waypoint x="432" y="117" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNShape id="_BPMNShape_StartEvent_2" bpmnElement="StartEvent_1">
        <dc:Bounds x="179" y="99" width="36" height="36" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="175" y="142" width="45" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Activity_1dxqxj0_di" bpmnElement="Activity_Charge">
        <dc:Bounds x="270" y="77" width="100" height="80" />
        <bpmndi:BPMNLabel />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_0qnrvvd_di" bpmnElement="EndEvent_1">
        <dc:Bounds x="432" y="99" width="36" height="36" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="428" y="142" width="45" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNShape>
    </bpmndi:BPMNPlane>
  </bpmndi:BPMNDiagram>
</bpmn:definitions>

開發Java實現刷卡付款業務

maven 國內源

maven 配置文件設置國內源, 文件:conf\settings.xml

  <mirrors>
         <mirror>
            <id>aliyun</id>
            <name>mirror from maven aliyun</name>
            <url>https://maven.aliyun.com/repository/central</url>
            <mirrorOf>central</mirrorOf>
        </mirror>
  </mirrors>

pom.xml

</dependency>
        <dependency>
            <groupId>org.camunda.bpm</groupId>
            <artifactId>camunda-external-task-client</artifactId>
            <version>7.17.0</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>1.6.1</version>
        </dependency>
        <dependency>
            <groupId>javax.xml.bind</groupId>
            <artifactId>jaxb-api</artifactId>
            <version>2.3.1</version>
        </dependency>
</dependencies>

java 業務代碼

camunda 的 ExternalTaskClient 是一個Listener類, 我們程序使用 ExternalTaskClient 就可以成為一個后臺daemon程序, 后面再專門寫個博客分析一下 camunda-external-task-client jar.
在我們的程序中, 使用ExternalTaskClient可以非常方便監聽流程中的External Task Service設定的 topic, 完成業務處理, 并標記該Task為結束.

package javatest;

import java.text.MessageFormat;
import java.util.logging.Logger;

import org.camunda.bpm.client.ExternalTaskClient;

public class ChargeCardWorker {
	private final static Logger logger = Logger.getLogger(ChargeCardWorker.class.getName());

	public static void main(String[] args) {
		logger.info("ExternalTaskClient setup");
		ExternalTaskClient client = ExternalTaskClient.create().baseUrl("http://localhost:8080/engine-rest")
				.asyncResponseTimeout(10000).build();

		// 訂閱并處理第1個ExternalTask的topic
		client.subscribe("charge-card").lockDuration(1000).handler((externalTask, externalTaskService) -> {
			// 獲取流程信息
			String item = (String) externalTask.getVariable("item");
			Long amount = (Long) externalTask.getVariable("amount");

			// 業務邏輯
			logger.info(
					MessageFormat.format("Charging credit card with an amount of {0} for the item {1}", amount, item));

			// 完成 Task
			externalTaskService.complete(externalTask);
		}).open();

		// 訂閱并處理第2個ExternalTask的topic
		// 省略

		logger.info("Listening topics...");
	}
}

啟動流程

確保java程序提前運行, 然后使用VS code+Rest Client 發起一個啟動流程命令:

POST http://localhost:8080/engine-rest/process-definition/key/payment-retrieval/start HTTP/1.1
Content-Type: application/json

{
    "variables": {
        "amount": {
            "value":555,
            "type":"long"
        },
        "item": {
            "value": "item-xyz"
        }
    }
}

Rest API的返回信息: