实时获取当前流程对应的流程图片，并对当前正在审批的节点进行高亮显示。

public class ActivitiController {
    @Autowired
    private ProcessEngine processEngine;

    @Autowired
    private RepositoryService repositoryService;

    @Autowired
    private RuntimeService runtimeService;
    

    /**
     * 生成正在执行的流程图
     */
    @RequestMapping(value = "processDiagram")
    public void genProcessDiagram(HttpServletResponse httpServletResponse, String processInstanceId) throws Exception {
        List<Execution> executions = runtimeService.createExecutionQuery()
                .processInstanceId(processInstanceId)
                .list();

        List<String> highLightedActivities = new ArrayList<>();
        List<String> highLightedFlows = new ArrayList<>();
        for (Execution exe : executions) {
            List<String> ids = runtimeService.getActiveActivityIds(exe.getId());
            highLightedActivities.addAll(ids);
        }

        //获取流程图
        ProcessInstance processInstance = runtimeService.createProcessInstanceQuery().processInstanceId(processInstanceId).singleResult();
        BpmnModel bpmnModel = repositoryService.getBpmnModel(processInstance.getProcessDefinitionId());
        ProcessEngineConfiguration engconf = processEngine.getProcessEngineConfiguration();
        ProcessDiagramGenerator diagramGenerator = engconf.getProcessDiagramGenerator();
        InputStream in = diagramGenerator.generateDiagram(bpmnModel,
                "png",
                highLightedActivities,
                highLightedFlows,
                engconf.getActivityFontName(), engconf.getLabelFontName(),
                engconf.getAnnotationFontName(), engconf.getClassLoader(),
                1.0);

        OutputStream out = null;
        byte[] buf = new byte[1024];
        int legth = 0;
        try {
            out = httpServletResponse.getOutputStream();
            while ((legth = in.read(buf)) != -1) {
                out.write(buf, 0, legth);
            }
        } finally {
            if (in != null) {
                in.close();
            }
            if (out != null) {
                out.close();
            }
        }
    }
}