Understand activity workflow

One 、 What is workflow

　　 Take leave for example , Now the leave process of most companies is like this

　　 Employees call （ Or online chat ） Apply to the superior for leave —— The superior verbally agreed —— The superior recorded the leave —— Submit the leave record to the company at the end of the month —— The company will enter the leave into the computer

　　 The leave process of companies using workflow technology is like this

　　 Employees log in to the system with an account —— Click leave —— The superior logs in to the system and clicks allow

　　 That's it , A leave process is over

　　 Someone will ask. , The superior doesn't have to submit leave records to the company ？ Companies don't have to enter records into computers ？ The answer is , With . But all this work will run automatically after the superior clicks allow ！

　　 This is workflow technology .

　　Georgakopoulos The workflow definition given is ： Workflow is to organize a group of tasks to complete a certain business process ： The trigger sequence and trigger conditions of the task are defined , Each task can be completed by one or more software systems , It can also be done by one or a group of people , It can also be done by one or more people working with the software system .

　　
　　 Two 、 The advantages of Workflow Technology
　　
　　 From the example above , It's easy to see

　　 Workflow system , Realize the automation of work flow , Improve the efficiency of enterprise operation 、 Improve the utilization of enterprise resources 、 Improve the flexibility and adaptability of enterprise operation 、 Improve the efficiency of quantitative assessment business processing 、 Reduce waste （ Time is money ）.

　　 And manual workflow , On the one hand, it is unable to effectively track the whole process 、 understand , On the other hand, human error and time delay will inevitably lead to low efficiency , In particular, it is impossible to make quantitative statistics , Not conducive to query 、 Statement and performance evaluation .

　　 3、 ... and 、 Java Why would developers learn to Activity workflow
　　
　　 stay Java field ,JBPM and Activity It's two mainstream workflow systems , and Activity The emergence of will undoubtedly replace JBPM（Activity The developers of are from Jbpm Developers come out of ）.

　　 Four 、 Activity Workflow learning points

　　1、1 A plug-in

　　 stay Eclipse Install in Activity plug-in unit , So that you can be in Eclipse Draw in Activity Workflow diagram

　　2、1 Engines

　　ProcessEngine object ,Activity Workflow engine . This is a Activiti The core of the work . Responsible for generating various instances and data of process runtime 、 Monitor and manage the operation of processes .

　　 All operations start with the get engine , So we usually use the engine as a global variable

ProcessEngine processEngine =ProcessEngines.getDefaultProcessEngine();
 
  

 
  

   
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　　3、1 Configuration files

　　activiti.cfg.xml.Activiti Core profile , Configure the basic parameters of the process engine creation tool and database connection pool parameters

　　4、5 Kinds of database tables

　　Activiti The backstage is supported by database , All watches use ACT_ start . The second part is a two letter sign indicating the purpose of the table . Uses and services API Corresponding .

　　ACT_RE_*: ‘RE’ Express repository. The prefixed table contains process definitions and process static resources （ picture , The rules , wait ）.

　　ACT_RU_*: ‘RU’ Express runtime. These runtime tables , Include process instances , Mission , Variable , Asynchronous task , Wait for the data in operation . Activiti Save the data only during the process instance execution , These records are deleted at the end of the process . In this way, the runtime table can always be very small and fast .

　　ACT_ID_*: ‘ID’ Express identity. These tables contain identity information , Such as user , Group, etc .

　　ACT_HI_*: ‘HI’ Express history. These tables contain historical data , For example, historical process examples , Variable , Tasks, etc .

　　ACT_GE_*: General data , Used in different scenes , Such as storing resource files .
　
　　5、23 A watch

　　 Different tables hold different kinds of data , There is a process definition table 、 Task node table 、 Process variable table 、 Task history table and so on .

6、5 term Service

　　 Different Service Class corresponds to different functions .

　　 such as TaskService, yes activiti Task service class . You can get task information from this class .

　　 and HistoryService, It is activiti The query history information class . After a process is completed , This object provides us with query history information .

7、7 Basic operations

　　　　 Design flow chart （ Various components , If connected 、 User tasks 、 gateway ）

　　　　 Add, delete, modify and check the process definition

　　　　 Add, delete, and modify process variables

　　　　 Start process definition

　　　　 Add, delete, change and check tasks

　　　　 To complete the task

　　　　 Historical information inquiry

　　 Study 7 The basic operation only needs to be performed in JavaSE The next step is to execute , Of course , do web We should consider and SSH And so on . Of course , Only basic operation can learn , Comprehensive development is not difficult .
　　

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