Activiti 获取流程图片

基于 Activiti 6.0
获取流程定义图片：1.流程定义；2.任务实例

1. 获取流程定义图

Controller 方法
@GetMapping("processDefinitionImage")
public void processDefinitionImage(String processDefinitionId, HttpServletResponse response) throws IOException {

    if (StringUtils.isBlank(processDefinitionId)) {
        throw new FormValidException("processDefinitionId 不能为空!");
    }
    InputStream inputStream = processService.getDefinitionImage(processDefinitionId);
    OutputStream outputStream = response.getOutputStream();
    HttpUtils.copyImageStream(inputStream, outputStream);
}

方法:processService.getDefinitionImage
/**
* 获取流程定义图片
*
* @param processDefinitionId
* @return
*/
public InputStream getDefinitionImage(String processDefinitionId) {

    ProcessDefinition processDefinition = repositoryService.createProcessDefinitionQuery().processDefinitionId(processDefinitionId).singleResult();
    InputStream inputStream = repositoryService.getResourceAsStream(processDefinition.getDeploymentId(), processDefinition.getDiagramResourceName());
    return inputStream;
}

使用 apache common-io包进行流操作
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-io</artifactId>
<version>1.3.2</version>
</dependency>

通用流处理类
package com.oldguy.example.modules.workflow.utils;

import org.apache.commons.io.IOUtils;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**

• @author huangrenhao

• @date 2019/1/22
  */
  public class HttpUtils {

  public static void copyImageStream(InputStream inputStream,OutputStream outputStream){
  try {
  IOUtils.copy(inputStream,outputStream);
  } catch (IOException e) {
  e.printStackTrace();
  }finally {
  try {
  inputStream.close();
  outputStream.close();
  } catch (IOException e) {
  e.printStackTrace();
  }
  }
  }
  }

流程定义图

processDefinitionImage.png

1. 获取任务图

   取任务图的时候，需要涉及动态节点，而流程定义图是静态的，所以需要涉及动态流程图创建。其中Activiti 提供了流程图创建类。

    Activiti 是基于BPMN流程图的，所以在Activiti中会有一个类: org.activiti.bpmn.model.BpmnModel ,l来描述 BPMN.xml 的信息。
    由BpmnModel可以获取流程定义类: org.activiti.bpmn.model.Process，用于描述流程各个节点与信息
    通过当前任务节点的Key，来获取流程信息流程节点类: org.activiti.bpmn.model.FlowElement，到此就可以获取到流程信息
    通过Activiti 提供到图片渲染类：org.activiti.image.impl.DefaultProcessDiagramGenerator，根据BpmnModel对象，动态生成流程图。
   

Controller 方法
@GetMapping("ProcessInstanceImage/{taskId}")
public void currentProcessInstanceImage(@PathVariable("taskId") String taskId, HttpServletResponse response) throws IOException {
InputStream inputStream = userTaskService.currentProcessInstanceImage(taskId);
OutputStream outputStream = response.getOutputStream();
HttpUtils.copyImageStream(inputStream, outputStream);
}

userTaskService.currentProcessInstanceImage(taskId); 获取当前节点流程任务图
/**
* 获取当前任务流程图
*
* @param taskId
* @return
*/
public InputStream currentProcessInstanceImage(String taskId) {

    Task task = taskService.createTaskQuery().taskId(taskId).singleResult();
    ProcessDefinition processDefinition = repositoryService.getProcessDefinition(task.getProcessDefinitionId());
    BpmnModel bpmnModel = repositoryService.getBpmnModel(task.getProcessDefinitionId());
    // ID 为 流程定义Key
    Process process = bpmnModel.getProcessById(processDefinition.getKey());

// UserTask userTask = (UserTask) process.getFlowElement(task.getTaskDefinitionKey());
// 流程节点ID
FlowElement flowElement = process.getFlowElement(task.getTaskDefinitionKey());

    DefaultProcessDiagramGenerator generator = new DefaultProcessDiagramGenerator();


    List<String> highLightedActivities = new ArrayList<>();
    highLightedActivities.add(flowElement.getId());

// 生成流程图
// InputStream inputStream = generator.generateJpgDiagram(bpmnModel);
// InputStream inputStream = generator.generatePngDiagram(bpmnModel);
// InputStream inputStream = generator.generateDiagram(bpmnModel, "jpg", highLightedActivities);

// 生成图片
InputStream inputStream = generator.generateDiagram(bpmnModel, "jpg", highLightedActivities, Collections.emptyList(), "宋体", "宋体", "宋体", null, 2.0);
return inputStream;
}

当前任务流程图

taskDefinitionImage.jpg

到此完成了流程图获取。