camunda如何调用HTTP REST（Service Task）服务节点

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Camunda中的Service Task（服务任务）用于调用服务。在Camunda中，可以通过调用本地Java代码、外部工作项、web服务形式实现的逻辑来完成的。

本文重点描述如何使用web服务实现Camunda服务调用，即如何使用camunda Connector连接器调用HTTP服务，本地Java代码和外部工作项后续文章中再详细介绍。

Camunda Connect提供HTTP和SOAP HTTP连接器。本示例演示了使用http连接器从Camunda BPM中的服务任务调用REST服务。

一、添加项目依赖

给项目中添加camunda connect 和 camunda spin 包依赖，重新启动camunda Platform。

<dependency>
    <groupId>org.camunda.bpm</groupId>
    <artifactId>camunda-engine-plugin-connect</artifactId>
    <version>7.15.0</version>
</dependency>

<dependency>
    <groupId>org.camunda.bpm</groupId>
    <artifactId>camunda-engine-plugin-spin</artifactId>
    <version>7.15.0</version>
</dependency>
<dependency>
    <groupId>org.camunda.spin</groupId>
    <artifactId>camunda-spin-dataformat-json-jackson</artifactId>
    <version>1.10.1</version>
</dependency>
<dependency>
    <groupId>org.camunda.spin</groupId>
    <artifactId>camunda-spin-core</artifactId>
    <version>1.10.1</version>
</dependency>
<dependency>
    <groupId>org.camunda.spin</groupId>
    <artifactId>camunda-spin-dataformat-all</artifactId>
    <version>1.10.1</version>
</dependency>

二、设计流程图

编辑

以下时服务节点的关键配置项：

HTTP连接器可用于创建新请求、设置HTTP方法、URL、内容类型和有效负载。

The HTTP connector can be used to create a new request, set a HTTP method, URL, content type and payload.

Parameter	Description
method	Sets the HTTP method of the request
url	Sets the URL of the request
headers	Contains a map of the configured HTTP headers of the request
payload	Sets the payload of the request

编辑

返回值包含状态码、响应头和响应体。

A response contains the status code, response headers and body.

Parameter	Description
statusCode	Contains the status code of the response
headers	Contains a map with the HTTP headers of the response
response	Contains the response body

编辑

以下是完整的BPMN模型文件：

<?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_1qvw7a2" targetNamespace="http://bpmn.io/schema/bpmn" exporter="Camunda Modeler" exporterVersion="4.8.1" modeler:executionPlatform="Camunda Platform" modeler:executionPlatformVersion="7.15.0"> <bpmn:process id="Process_0a6gw7u" name="贷款申请流程HTTP" isExecutable="true"> <bpmn:startEvent id="StartEvent_1"> <bpmn:outgoing>Flow_0kzdck2</bpmn:outgoing> </bpmn:startEvent> <bpmn:sequenceFlow id="Flow_0kzdck2" sourceRef="StartEvent_1" targetRef="Activity_0bvh293" /> <bpmn:sequenceFlow id="Flow_07gaddc" sourceRef="Activity_0bvh293" targetRef="Activity_0kimj7k" /> <bpmn:serviceTask id="Activity_0bvh293" name="贷款额度计算"> <bpmn:extensionElements> <camunda:connector> <camunda:inputOutput> <camunda:inputParameter name="headers"> <camunda:map> <camunda:entry key="Content-Type">text/plain</camunda:entry> <camunda:entry key="Accept">application/json</camunda:entry> </camunda:map> </camunda:inputParameter> <camunda:inputParameter name="method">POST</camunda:inputParameter> <camunda:inputParameter name="url">http://127.0.0.1:8888/userLoan/computeLoan?yearWages=${yearWages}&houseAssets=${houseAssets}</camunda:inputParameter> <camunda:outputParameter name="creditRating"> <camunda:script scriptFormat="JavaScript">var response = connector.getVariable("response"); var user = S(response); var creditRating = user.prop("creditRating").stringValue(); creditRating;</camunda:script> </camunda:outputParameter> <camunda:outputParameter name="loanLimit"> <camunda:script scriptFormat="JavaScript">var response = connector.getVariable("response"); var user = S(response); var loanLimit = user.prop("loanLimit").numberValue(); loanLimit;</camunda:script> </camunda:outputParameter> <camunda:outputParameter name="loanUser">${response}</camunda:outputParameter> </camunda:inputOutput> <camunda:connectorId>http-connector</camunda:connectorId> </camunda:connector> </bpmn:extensionElements> <bpmn:incoming>Flow_0kzdck2</bpmn:incoming> <bpmn:outgoing>Flow_07gaddc</bpmn:outgoing> </bpmn:serviceTask> <bpmn:userTask id="Activity_0kimj7k" name="确认贷款额度" camunda:assignee="demo"> <bpmn:incoming>Flow_07gaddc</bpmn:incoming> <bpmn:outgoing>Flow_09mofy3</bpmn:outgoing> </bpmn:userTask> <bpmn:sequenceFlow id="Flow_09mofy3" sourceRef="Activity_0kimj7k" targetRef="Event_0myx83u" /> <bpmn:endEvent id="Event_0myx83u"> <bpmn:incoming>Flow_09mofy3</bpmn:incoming> </bpmn:endEvent> </bpmn:process> <bpmndi:BPMNDiagram id="BPMNDiagram_1"> <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="Process_0a6gw7u"> <bpmndi:BPMNEdge id="Flow_09mofy3_di" bpmnElement="Flow_09mofy3"> <di:waypoint x="570" y="117" /> <di:waypoint x="662" y="117" /> </bpmndi:BPMNEdge> <bpmndi:BPMNEdge id="Flow_07gaddc_di" bpmnElement="Flow_07gaddc"> <di:waypoint x="370" y="117" /> <di:waypoint x="470" y="117" /> </bpmndi:BPMNEdge> <bpmndi:BPMNEdge id="Flow_0kzdck2_di" bpmnElement="Flow_0kzdck2"> <di:waypoint x="215" y="117" /> <di:waypoint x="270" y="117" /> </bpmndi:BPMNEdge> <bpmndi:BPMNShape id="_BPMNShape_StartEvent_2" bpmnElement="StartEvent_1"> <dc:Bounds x="179" y="99" width="36" height="36" /> </bpmndi:BPMNShape> <bpmndi:BPMNShape id="Activity_0rfgq1k_di" bpmnElement="Activity_0bvh293"> <dc:Bounds x="270" y="77" width="100" height="80" /> </bpmndi:BPMNShape> <bpmndi:BPMNShape id="Activity_16ovae8_di" bpmnElement="Activity_0kimj7k"> <dc:Bounds x="470" y="77" width="100" height="80" /> </bpmndi:BPMNShape> <bpmndi:BPMNShape id="Event_0myx83u_di" bpmnElement="Event_0myx83u"> <dc:Bounds x="662" y="99" width="36" height="36" /> </bpmndi:BPMNShape> </bpmndi:BPMNPlane> </bpmndi:BPMNDiagram> </bpmn:definitions>

三、开发HTTP服务

1. 新建springboot工程，开发User类

import java.io.Serializable;public class User implements Serializable { private String userName; //姓名 private int userAge; //年龄 private double yearWages; //年薪 private double houseAssets; //房产 private String creditRating; //信用等级 private double loanLimit; //贷款额度 private String isTransferAccount; //是否已放贷 public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } public int getUserAge() { return userAge; } public void setUserAge(int userAge) { this.userAge = userAge; } public double getYearWages() { return yearWages; } public void setYearWages(double yearWages) { this.yearWages = yearWages; } public double getHouseAssets() { return houseAssets; } public void setHouseAssets(double houseAssets) { this.houseAssets = houseAssets; } public String getCreditRating() { return creditRating; } public void setCreditRating(String creditRating) { this.creditRating = creditRating; } public double getLoanLimit() { return loanLimit; } public void setLoanLimit(double loanLimit) { this.loanLimit = loanLimit; } public String getIsTransferAccount() { return isTransferAccount; } public void setIsTransferAccount(String isTransferAccount) { this.isTransferAccount = isTransferAccount; } }

2. 开发REST服务类

import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PostMapping; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController;@RestController @RequestMapping("/userLoan") public class UserLoanController { @PostMapping("/computeLoan") public User computeLoan(double yearWages,double houseAssets){ User user=new User(); user.setYearWages(yearWages); user.setHouseAssets(houseAssets); double sum = yearWages + houseAssets; if(sum<=0){ user.setCreditRating("C"); user.setLoanLimit(0); }else if(sum>0 && sum <=100){ user.setCreditRating("B"); user.setLoanLimit(sum*0.8); }else if(sum>100){ user.setCreditRating("A"); user.setLoanLimit(sum*1.2); } return user; } }