Flowable深入淺出-1 Flowable簡介
1 Flowable簡介
什麼是BPMN
先來看下百度百科的定義：
由BPMI(The Business Process Management Initiative)開發了一套標準叫業務流程建模符號(BPMN - Business Process Modeling Notation)。在 BPMI Notation Working Group超過2年的努力，於2004年5月對外發布了BPMN 1.0 規範。後BPMI併入到OMG組織，OMG於2011年推出BPMN2.0標準，對BPMN進行了重新定義**(Business Process Model and Notation**)。BPMN的主要目標是提供一些被所有業務使用者容易理解的符號，從建立流程輪廓的業務分析到這些流程的實現，直到終端使用者的管理監控。BPMN也支援提供一個內部的模型可以生成可執行的BPEL4WS。因此BPMN的出現，彌補了從業務流程設計到流程開發的間隙。
BPMN定義了一個業務流程圖（Business Process Diagram），該業務流程圖基於一個流程圖（flowcharting），該流程圖被設計用於建立業務流程操作的圖形化模型。而一個業務流程模型（Business Process Model），指一個由圖形物件（graphical objects）組成的網狀圖，圖形物件包括活動（activities)和用於定義這些活動執行順序的流程控制器（flow controls）。
大白話理解：
BPMN是一套符號的標準，這些符號描述瞭如果做一個業務，並且這個業務在做的過程中被人監控和控制。業務人員和開發人員通過這套圖形可以很好的完成協作。
什麼是Flowable
官方描述如下：
Flowable提供了一個組高效的核心開源業務流程引擎，為開發人員，系統管理員和業務使用者提供工作流和業務流程管理（BPM）平臺。全部用Java編寫，並且基於Apache 2.0許可的開源，程式碼在社群維護。其核心是一個快速，經過試驗和測試的動態BPMN流程引擎，附帶DMN決策表和CMMN Case管理引擎.
大白話理解：
Flowable是BPMN的一個基於java的軟體實現，不過Flowable不僅僅包括BPMN，還有DMN決策表和CMMN Case管理引擎，並且有自己的使用者管理、微服務API等一系列功能，是一個服務平臺。
Flowable官網、開源社群
Flowable官方網站：
https://www.flowable.org/
Flowable開原始碼倉庫：
https://github.com/flowable/flowable-engine
Flowable 最新版本(V6.4.0)截止目前下載地址:
Tomcat 版本安裝包：
https://download.csdn.net/download/houyj1986/10871025
https://github.com/flowable/flowable-engine/releases/download/flowable-6.4.0/tomcat-flowable-6.4.0.zip
EAR版本版本安裝包：
https://download.csdn.net/download/houyj1986/10871018
https://github.com/flowable/flowable-engine/releases/download/flowable-6.4.0/flowable-6.4.0.zip
Flowable原始碼（V6.4.0）下載地址：
https://download.csdn.net/download/houyj1986/10871014
Flowable流程示例
一個簡單度假申請流程主要過程如下：
1、員工提交請假資訊，如工號，請假天數
2、經理點選審批通過或者拒絕
3、如果拒絕直接進入系統發郵件服務通知員工
4、如果通過系統記錄該員工的請假天數，減少可用天數
5、員工看到自己請假審批通過，點選完成請假。
Flowable的BPMN流程圖: 
流程圖的BMPN檔案如下:
<?xml version="1.0" encoding="UTF-8"?>
<definitions xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:flowable="http://flowable.org/bpmn" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:omgdc="http://www.omg.org/spec/DD/20100524/DC" xmlns:omgdi="http://www.omg.org/spec/DD/20100524/DI" typeLanguage="http://www.w3.org/2001/XMLSchema" expressionLanguage="http://www.w3.org/1999/XPath" targetNamespace="http://www.flowable.org/processdef">
<process id="holidayRequest" name="Holiday Request" isExecutable="true">
<startEvent id="startEvent"></startEvent>
<sequenceFlow id="sequenceFlow-3fa7af74-df9a-4d3a-b0eb-10b20e7dc202" sourceRef="startEvent" targetRef="approveTask"></sequenceFlow>
<userTask id="approveTask" name="經理通過或駁回申請"></userTask>
<sequenceFlow id="sequenceFlow-d9127dc0-158f-4169-b61b-99226ffe8494" sourceRef="approveTask" targetRef="decision"></sequenceFlow>
<exclusiveGateway id="decision"></exclusiveGateway>
<serviceTask id="externalSystemCall" name="系統記錄申請天數" flowable:class="org.flowable.CallExternalSystemDelegate"></serviceTask>
<sequenceFlow id="sequenceFlow-6232f578-3975-4d7e-81f2-43b242d33ebd" sourceRef="externalSystemCall" targetRef="holidayApprovedTask"></sequenceFlow>
<userTask id="holidayApprovedTask" name="員工檢視申請通過"></userTask>
<sequenceFlow id="sequenceFlow-29fd3375-9bcb-42f2-bb6f-63ae1f98813a" sourceRef="holidayApprovedTask" targetRef="approveEnd"></sequenceFlow>
<serviceTask id="sendRejectionMail" name="傳送駁回郵件" flowable:class="org.flowable.SendRejectionMail"></serviceTask>
<sequenceFlow id="sequenceFlow-b390b442-2411-44a9-96eb-3c129d4c8408" sourceRef="sendRejectionMail" targetRef="rejectEnd"></sequenceFlow>
<endEvent id="approveEnd"></endEvent>
<endEvent id="rejectEnd"></endEvent>
<sequenceFlow id="sequenceFlow-6f21d3e2-2e49-4b00-9aae-0b71d861a177" name="駁回" sourceRef="decision" targetRef="sendRejectionMail">
<conditionExpression xsi:type="tFormalExpression"><![CDATA[${!approved}]]></conditionExpression>
</sequenceFlow>
<sequenceFlow id="sequenceFlow-2470619b-fa36-440b-a231-b7bd226c23bb" name="通過" sourceRef="decision" targetRef="externalSystemCall">
<conditionExpression xsi:type="tFormalExpression"><![CDATA[${approved}]]></conditionExpression>
</sequenceFlow>
</process>
<bpmndi:BPMNDiagram id="BPMNDiagram_holidayRequest">
<bpmndi:BPMNPlane bpmnElement="holidayRequest" id="BPMNPlane_holidayRequest">
<bpmndi:BPMNShape bpmnElement="startEvent" id="BPMNShape_startEvent">
<omgdc:Bounds height="30.0" width="30.0" x="0.0" y="95.0"></omgdc:Bounds>
</bpmndi:BPMNShape>
<bpmndi:BPMNShape bpmnElement="approveTask" id="BPMNShape_approveTask">
<omgdc:Bounds height="60.0" width="100.0" x="80.0" y="80.0"></omgdc:Bounds>
</bpmndi:BPMNShape>
<bpmndi:BPMNShape bpmnElement="decision" id="BPMNShape_decision">
<omgdc:Bounds height="40.0" width="40.0" x="230.0" y="90.0"></omgdc:Bounds>
</bpmndi:BPMNShape>
<bpmndi:BPMNShape bpmnElement="externalSystemCall" id="BPMNShape_externalSystemCall">
<omgdc:Bounds height="60.0" width="100.0" x="320.0" y="1.0"></omgdc:Bounds>
</bpmndi:BPMNShape>
<bpmndi:BPMNShape bpmnElement="holidayApprovedTask" id="BPMNShape_holidayApprovedTask">
<omgdc:Bounds height="60.0" width="100.0" x="470.0" y="1.0"></omgdc:Bounds>
</bpmndi:BPMNShape>
<bpmndi:BPMNShape bpmnElement="sendRejectionMail" id="BPMNShape_sendRejectionMail">
<omgdc:Bounds height="60.0" width="100.0" x="320.0" y="160.0"></omgdc:Bounds>
</bpmndi:BPMNShape>
<bpmndi:BPMNShape bpmnElement="approveEnd" id="BPMNShape_approveEnd">
<omgdc:Bounds height="28.0" width="28.0" x="620.0" y="16.0"></omgdc:Bounds>
</bpmndi:BPMNShape>
<bpmndi:BPMNShape bpmnElement="rejectEnd" id="BPMNShape_rejectEnd">
<omgdc:Bounds height="28.0" width="28.0" x="505.0" y="175.0"></omgdc:Bounds>
</bpmndi:BPMNShape>
<bpmndi:BPMNEdge bpmnElement="sequenceFlow-2470619b-fa36-440b-a231-b7bd226c23bb" id="BPMNEdge_sequenceFlow-2470619b-fa36-440b-a231-b7bd226c23bb">
<omgdi:waypoint x="250.0" y="90.0"></omgdi:waypoint>
<omgdi:waypoint x="250.0" y="31.0"></omgdi:waypoint>
<omgdi:waypoint x="319.99999999999284" y="31.0"></omgdi:waypoint>
</bpmndi:BPMNEdge>
<bpmndi:BPMNEdge bpmnElement="sequenceFlow-3fa7af74-df9a-4d3a-b0eb-10b20e7dc202" id="BPMNEdge_sequenceFlow-3fa7af74-df9a-4d3a-b0eb-10b20e7dc202">
<omgdi:waypoint x="29.949998618355412" y="110.0"></omgdi:waypoint>
<omgdi:waypoint x="80.0" y="110.0"></omgdi:waypoint>
</bpmndi:BPMNEdge>
<bpmndi:BPMNEdge bpmnElement="sequenceFlow-6232f578-3975-4d7e-81f2-43b242d33ebd" id="BPMNEdge_sequenceFlow-6232f578-3975-4d7e-81f2-43b242d33ebd">
<omgdi:waypoint x="419.95000000000005" y="31.0"></omgdi:waypoint>
<omgdi:waypoint x="470.0" y="31.0"></omgdi:waypoint>
</bpmndi:BPMNEdge>
<bpmndi:BPMNEdge bpmnElement="sequenceFlow-b390b442-2411-44a9-96eb-3c129d4c8408" id="BPMNEdge_sequenceFlow-b390b442-2411-44a9-96eb-3c129d4c8408">
<omgdi:waypoint x="419.949999999997" y="189.66442953020135"></omgdi:waypoint>
<omgdi:waypoint x="505.00030595247523" y="189.0936221647077"></omgdi:waypoint>
</bpmndi:BPMNEdge>
<bpmndi:BPMNEdge bpmnElement="sequenceFlow-d9127dc0-158f-4169-b61b-99226ffe8494" id="BPMNEdge_sequenceFlow-d9127dc0-158f-4169-b61b-99226ffe8494">
<omgdi:waypoint x="179.9499999999898" y="110.0"></omgdi:waypoint>
<omgdi:waypoint x="230.0" y="110.0"></omgdi:waypoint>
</bpmndi:BPMNEdge>
<bpmndi:BPMNEdge bpmnElement="sequenceFlow-29fd3375-9bcb-42f2-bb6f-63ae1f98813a" id="BPMNEdge_sequenceFlow-29fd3375-9bcb-42f2-bb6f-63ae1f98813a">
<omgdi:waypoint x="569.9499999999988" y="31.0"></omgdi:waypoint>
<omgdi:waypoint x="582.0" y="31.0"></omgdi:waypoint>
<omgdi:waypoint x="582.0" y="31.0"></omgdi:waypoint>
<omgdi:waypoint x="620.0025321198765" y="30.268220825690175"></omgdi:waypoint>
</bpmndi:BPMNEdge>
<bpmndi:BPMNEdge bpmnElement="sequenceFlow-6f21d3e2-2e49-4b00-9aae-0b71d861a177" id="BPMNEdge_sequenceFlow-6f21d3e2-2e49-4b00-9aae-0b71d861a177">
<omgdi:waypoint x="250.0" y="129.9375468164794"></omgdi:waypoint>
<omgdi:waypoint x="250.0" y="190.0"></omgdi:waypoint>
<omgdi:waypoint x="319.99999999997794" y="190.0"></omgdi:waypoint>
</bpmndi:BPMNEdge>
</bpmndi:BPMNPlane>
</bpmndi:BPMNDiagram>
</definitions>
檔名為Holiday_Request.bpmn20.xml，flowable支援以BPMN和bpmn20.xml結尾的流程檔案。上面的xml看起來非常恐怖，不用擔心，後面我會介紹Flowable的專門的流程繪製軟體。
以上主要讓大家對Flowable有個簡單的瞭解，下一節介紹如何啟動Flowable，並且介紹Flowable的啟動包的相關內容。
版權
轉載請聯絡作者，謝謝。由書山登峰人創作。