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

<code>&lt;properties&gt;
  &lt;maven.compiler.source&gt;8&lt;/maven.compiler.source&gt;
  &lt;maven.compiler.target&gt;8&lt;/maven.compiler.target&gt;
  &lt;project.build.sourceEncoding&gt;UTF-8&lt;/project.build.sourceEncoding&gt;
  &lt;flowable.version&gt;6.6.0&lt;/flowable.version&gt;
&lt;/properties&gt;

&lt;parent&gt;
  &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
  &lt;artifactId&gt;spring-boot-starter-parent&lt;/artifactId&gt;
  &lt;version&gt;2.7.5&lt;/version&gt;
  &lt;relativePath/&gt;
&lt;/parent&gt;

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

Configuration

application.properties (can be changed to YAML)

<code># 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</code>

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.

<code>@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");
    }
}
</code>

Result – simple response wrapper.

<code>@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;
    }
}
</code>

TaskVO – encapsulates approval list items.

<code>@Data
@NoArgsConstructor
@AllArgsConstructor
public class TaskVO {
    private String id;
    private String day;
    private String name;
}
</code>

LeaveController – REST endpoints for the leave workflow.

<code>@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.
}
</code>

Process Diagram Generation

Method

genProcessDiagram

generates a PNG diagram for a running process instance.

<code>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();
}
</code>

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.

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

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

Additional resources: the open‑source

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