Flowable与springBoot项目整合及出现的问题

单纯地将Flowable和springBoot整合，使用mysql作为数据库，整合中踩了两个坑，见文末。
在pom中添加依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.0.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.happen</groupId>
    <artifactId>flowable1</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>flowable1</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.flowable/flowable-spring-boot-starter -->
        <dependency>
            <groupId>org.flowable</groupId>
            <artifactId>flowable-spring-boot-starter</artifactId>
            <version>6.6.0</version>
        </dependency>


        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

application.yml文件
database-schema-update: true的作用是自动更新数据库中需要的表，在第一次运行时必要

server:
  port: 8000

web:
  domain: http://localhost

spring:
  datasource:
    driverClassName: com.mysql.cj.jdbc.Driver
    username: root
    password: WHP199617whp
    url: jdbc:mysql://localhost:3306/flowable1?useUnicode=true&characterEncoding=utf8&autoReconnect=true&serverTimezone=GMT%2B8&nullCatalogMeansCurrent=true

flowable:
  async-executor-activate: false
  database-schema-update: true

Flowable1Application
对数据库中的流程数量进行查询

package com.happen.flowable1;

import org.flowable.engine.RepositoryService;
import org.flowable.engine.RuntimeService;
import org.flowable.engine.TaskService;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;

@SpringBootApplication(proxyBeanMethods = false)
public class Flowable1Application {

    public static void main(String[] args) {
        SpringApplication.run(Flowable1Application.class, args);
    }

    @Bean
    public CommandLineRunner init(final RepositoryService repositoryService,
                                  final RuntimeService runtimeService,
                                  final TaskService taskService) {

        return new CommandLineRunner() {
            @Override
            public void run(String... strings) throws Exception {
                System.out.println("Number of process definitions : "
                        + repositoryService.createProcessDefinitionQuery().count());
                System.out.println("Number of tasks : " + taskService.createTaskQuery().count());
                runtimeService.startProcessInstanceByKey("oneTaskProcess");
                System.out.println("Number of tasks after process start: "
                        + taskService.createTaskQuery().count());
            }
        };
    }
}

xml文件，这是一个 BPMN 2.0的标准文件

<?xml version="1.0" encoding="UTF-8"?>
<definitions
        xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL"
        xmlns:flowable="http://flowable.org/bpmn"
        targetNamespace="Examples">

    <process id="oneTaskProcess" name="The One Task Process">
        <startEvent id="theStart" />
        <sequenceFlow id="flow1" sourceRef="theStart" targetRef="theTask" />
        <userTask id="theTask" name="my task" flowable:assignee="kermit" />
        <sequenceFlow id="flow2" sourceRef="theTask" targetRef="theEnd" />
        <endEvent id="theEnd" />
    </process>

</definitions>

运行结果

会在数据库中生成对应的表

控制台中：

遇到的坑

1. 建表的时候出现 table ‘flowable1.act_id_user’ doesn’t exist
   这是因为之前本机上建过相同的表，现在不许重复建表了？在数据库配置时后面追加&nullCatalogMeansCurrent=true即可
2. nested exception is org.flowable.common.engine.api.FlowableException: Error initialising eventregistry data model
   将springboot版本设置为2.2.0.RELEASE即可（我试了2.4.5就是不行，真坑，不行就删了数据库中的所有表再试试）。