camunda_04_quickstart

最新推荐文章于 2024-02-05 09:31:43 发布

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#java #servlet #开发语言

本文介绍如何使用Camunda流程引擎设计并部署一个简单的支付流程，包括创建模型文件、配置Java业务逻辑以及启动流程等关键步骤。

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目标

设计和部署第一个简单流程
使用Java实现流程处理
完成流程启动测试

设计第一个流程

建模注意事项

模型文件和部署名其实并不重要,最重要是流程的Id, ProcessEngine是按照这个Id管理流程.
流程要设定为 Executable.

步骤

使用Model新建一个 camunda 7的模型文件, 命名为payment.bpm , 流程Id 设定为payment-retrieval , 并完成部署.
在流程中增加一个Service task, 类型选External,Topic设定为charge-card
BPMN xml 代码

<?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="付款请求">
      <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>

开发Java实现刷卡付款业务

maven 国内源

maven 配置文件设置国内源, 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 业务代码

camunda 的 ExternalTaskClient 是一个Listener类, 我们程序使用 ExternalTaskClient 就可以成为一个后台daemon程序, 后面再专门写个博客分析一下 camunda-external-task-client jar.
在我们的程序中, 使用ExternalTaskClient可以非常方便监听流程中的External Task Service设定的 topic, 完成业务处理, 并标记该Task为结束.

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();

		// 订阅并处理第1个ExternalTask的topic
		client.subscribe("charge-card").lockDuration(1000).handler((externalTask, externalTaskService) -> {
			// 获取流程信息
			String item = (String) externalTask.getVariable("item");
			Long amount = (Long) externalTask.getVariable("amount");

			// 业务逻辑
			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();

		// 订阅并处理第2个ExternalTask的topic
		// 省略

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

启动流程

确保java程序提前运行, 然后使用VS code+Rest Client 发起一个启动流程命令:

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:

Java程序端的输出: