基于 Activiti 6.0
獲取流程定義圖片：1.流程定義；2.任務(wù)實(shí)例

1. 獲取流程定義圖

Controller 方法

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

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

方法:processService.getDefinitionImage

    /**
     * 獲取流程定義圖片
     *
     * @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包進(jìn)行流操作

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-io</artifactId>
    <version>1.3.2</version>
</dependency>

通用流處理類

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();
            }
        }
    }
}

流程定義圖

processDefinitionImage.png

1. 獲取任務(wù)圖

取任務(wù)圖的時(shí)候，需要涉及動(dòng)態(tài)節(jié)點(diǎn)，而流程定義圖是靜態(tài)的，所以需要涉及動(dòng)態(tài)流程圖創(chuàng)建。其中Activiti 提供了流程圖創(chuàng)建類。

1. Activiti 是基于BPMN流程圖的，所以在Activiti中會(huì)有一個(gè)類: org.activiti.bpmn.model.BpmnModel ,l來描述 BPMN.xml 的信息。
2. 由BpmnModel可以獲取流程定義類: org.activiti.bpmn.model.Process，用于描述流程各個(gè)節(jié)點(diǎn)與信息
3. 通過當(dāng)前任務(wù)節(jié)點(diǎn)的Key，來獲取流程信息流程節(jié)點(diǎn)類: org.activiti.bpmn.model.FlowElement，到此就可以獲取到流程信息
4. 通過Activiti 提供到圖片渲染類：org.activiti.image.impl.DefaultProcessDiagramGenerator，根據(jù)BpmnModel對(duì)象，動(dòng)態(tài)生成流程圖。

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); 獲取當(dāng)前節(jié)點(diǎn)流程任務(wù)圖

    /**
     * 獲取當(dāng)前任務(wù)流程圖
     *
     * @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 為 流程定義Key
        Process process = bpmnModel.getProcessById(processDefinition.getKey());

//        UserTask userTask = (UserTask) process.getFlowElement(task.getTaskDefinitionKey());
        // 流程節(jié)點(diǎn)ID
        FlowElement flowElement = process.getFlowElement(task.getTaskDefinitionKey());

        DefaultProcessDiagramGenerator generator = new DefaultProcessDiagramGenerator();


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

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

// 生成圖片
        InputStream inputStream = generator.generateDiagram(bpmnModel, "jpg", highLightedActivities, Collections.emptyList(), "宋體", "宋體", "宋體", null, 2.0);
        return inputStream;
    }

當(dāng)前任務(wù)流程圖

taskDefinitionImage.jpg

到此完成了流程圖獲取。