Build a Spring Boot + Flowable Leave Approval System: Step‑by‑Step Guide

Program Related

Environment

jdk1.8

maven3

SpringBoot 2.7.5

flowable 6.6.0

MySQL8

Dependencies

<properties>
  <maven.compiler.source>8</maven.compiler.source>
  <maven.compiler.target>8</maven.compiler.target>
  <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  <flowable.version>6.6.0</flowable.version>
</properties>

<parent>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-parent</artifactId>
  <version>2.7.5</version>
  <relativePath/>
</parent>

<dependencies>
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
  </dependency>
  <!-- flowable jars -->
  <dependency>
    <groupId>org.flowable</groupId>
    <artifactId>flowable-spring-boot-starter</artifactId>
    <version>${flowable.version}</version>
  </dependency>
  <dependency>
    <groupId>org.flowable</groupId>
    <artifactId>flowable-spring-boot-starter-ui-idm</artifactId>
    <version>${flowable.version}</version>
  </dependency>
  <dependency>
    <groupId>org.flowable</groupId>
    <artifactId>flowable-spring-boot-starter-ui-modeler</artifactId>
    <version>${flowable.version}</version>
  </dependency>
  <dependency>
    <groupId>org.flowable</groupId>
    <artifactId>flowable-bpmn-layout</artifactId>
    <version>${flowable.version}</version>
  </dependency>
  <dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.31</version>
  </dependency>
  <dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.2.2</version>
  </dependency>
  <dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
  </dependency>
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
  </dependency>
</dependencies>

Configuration

application.properties (can be changed to YAML)

# Port
server.port=8081

# UI related
flowable.idm.app.admin.user-id=admin
flowable.idm.app.admin.password=admin
flowable.idm.app.admin.first-name=xxx
flowable.idm.app.admin.last-name=xxx
flowable.database-schema-update=true # create tables on first run

# Disable async job executor
flowable.async-executor-activate=false

# Database
spring.datasource.url=jdbc:mysql://xxxx:3306/flowable-test?autoReconnect=true&useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=GMT%2B8&nullCatalogMeansCurrent=true
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.type=com.zaxxer.hikari.HikariDataSource

# Logging
logging.level.org.flowable=DEBUG

Notes

&nullCatalogMeansCurrent=true must be appended to the JDBC URL, otherwise Flowable cannot create tables automatically.

Create a database named flowable before starting; Flowable will generate the required tables.

After the project starts, the login credentials are user-id: admin, password: admin.

Tables

Many tables are auto‑created; the exact count is not listed.

Classes

FlowableConfig – prevents Chinese characters from becoming garbled in generated diagrams.

@Configuration
public class FlowableConfig implements EngineConfigurationConfigurer<SpringProcessEngineConfiguration> {
    @Override
    public void configure(SpringProcessEngineConfiguration engineConfiguration) {
        engineConfiguration.setActivityFontName("宋体");
        engineConfiguration.setLabelFontName("宋体");
        engineConfiguration.setAnnotationFontName("宋体");
    }
}

Result – simple response wrapper.

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Result {
    private boolean flag;
    private String message;
    private Object data;
    public Result(boolean flag, String message) {
        this.flag = flag;
        this.message = message;
    }
}

TaskVO – encapsulates approval list items.

@Data
@NoArgsConstructor
@AllArgsConstructor
public class TaskVO {
    private String id;
    private String day;
    private String name;
}

LeaveController – REST endpoints for the leave workflow.

@RestController
@RequestMapping("/leave")
@Slf4j
public class LeaveController {
    @Autowired private RuntimeService runtimeService;
    @Autowired private TaskService taskService;
    @Autowired private RepositoryService repositoryService;
    @Autowired private ProcessEngine processEngine;

    @PostMapping("add/{day}/{studentUser}")
    public Result sub(@PathVariable("day") Integer day, @PathVariable("studentUser") String studentUser) {
        Map<String, Object> map = new HashMap<>();
        map.put("day", day);
        map.put("studentName", studentUser);
        ProcessInstance pi = runtimeService.startProcessInstanceByKey("stuLeave", map);
        Task task = taskService.createTaskQuery().processInstanceId(pi.getId()).singleResult();
        taskService.complete(task.getId());
        return new Result(true, "提交成功.流程Id为：" + pi.getId());
    }
    // teacher list, teacher approve/reject, dean list, dean approve/reject, re‑apply, process diagram, etc.
}

Process Diagram Generation

Method genProcessDiagram generates a PNG diagram for a running process instance.

public void genProcessDiagram(HttpServletResponse response, @PathVariable("taskId") String taskId) throws Exception {
    ProcessInstance pi = runtimeService.createProcessInstanceQuery().processInstanceId(taskId).singleResult();
    if (pi == null) return;
    Task task = taskService.createTaskQuery().processInstanceId(pi.getId()).singleResult();
    String instanceId = task.getProcessInstanceId();
    List<Execution> executions = runtimeService.createExecutionQuery().processInstanceId(instanceId).list();
    List<String> activityIds = new ArrayList<>();
    for (Execution exe : executions) {
        activityIds.addAll(runtimeService.getActiveActivityIds(exe.getId()));
    }
    BpmnModel bpmnModel = repositoryService.getBpmnModel(pi.getProcessDefinitionId());
    ProcessEngineConfiguration conf = processEngine.getProcessEngineConfiguration();
    ProcessDiagramGenerator generator = conf.getProcessDiagramGenerator();
    InputStream in = generator.generateDiagram(bpmnModel, "png", activityIds, new ArrayList<>(),
            conf.getActivityFontName(), conf.getLabelFontName(), conf.getAnnotationFontName(),
            conf.getClassLoader(), 1.0, true);
    response.setHeader("Content-Type", "image/png;charset=utf-8");
    OutputStream out = response.getOutputStream();
    byte[] buf = new byte[1024];
    int len;
    while ((len = in.read(buf)) != -1) {
        out.write(buf, 0, len);
    }
    in.close();
    out.close();
}

After building, run the application at http://localhost:8081 and log in with admin/admin.

Process Definition

Place the BPMN file 学生请假流程.bpmn20.xml under resources/processes. The XML defines start event, user tasks (apply, teacherPass, principalPass), an exclusive gateway that judges whether the leave exceeds two days, and the end event with conditional sequence flows.

<?xml version="1.0" encoding="UTF-8"?>
<definitions xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL" ...>
  <process id="stuLeave" name="学生请假流程" isExecutable="true">
    <startEvent id="startEvent1" name="开始"/>
    <userTask id="apply" name="请假申请" flowable:assignee="${studentName}"/>
    <userTask id="teacherPass" name="辅导员审批" flowable:candidateGroups="a"/>
    <exclusiveGateway id="judgeTask" name="判断是否大于2天"/>
    <userTask id="principalPass" name="院长审批" flowable:candidateGroups="b"/>
    <endEvent id="over" name="结束"/>
    <sequenceFlow id="flowBeg" sourceRef="startEvent1" targetRef="apply"/>
    <sequenceFlow id="sid-F3C3133B-68E1-4D1B-B06B-761EDD44E9F6" sourceRef="apply" targetRef="teacherPass"/>
    <sequenceFlow id="TeacherNotPassFlow" sourceRef="teacherPass" targetRef="apply">
      <conditionExpression xsi:type="tFormalExpression">${outcome=='驳回'}</conditionExpression>
    </sequenceFlow>
    <sequenceFlow id="teacherPassFlow" sourceRef="teacherPass" targetRef="judgeTask">
      <conditionExpression xsi:type="tFormalExpression">${outcome=="通过"}</conditionExpression>
    </sequenceFlow>
    <sequenceFlow id="judgeLess" sourceRef="judgeTask" targetRef="over">
      <conditionExpression xsi:type="tFormalExpression">${day<=2}</conditionExpression>
    </sequenceFlow>
    <sequenceFlow id="judgeMore" sourceRef="judgeTask" targetRef="principalPass">
      <conditionExpression xsi:type="tFormalExpression">${day>2}</conditionExpression>
    </sequenceFlow>
    ...
  </process>
</definitions>

Demo Screenshots

Submission, teacher approval list, process diagrams, dean approval/rejection, re‑apply, etc.

Database Table Overview

ACT_RE – repository tables (process definitions, resources)

ACT_RU – runtime tables (process instances, tasks, variables)

ACT_HI – history tables (completed instances, historic tasks)

ACT_GE – general tables used by various components

ACT_ID – identity tables (users, groups)

Author: 什人 Source: juejin.cn/post/7387380647269253146

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