我想追踪一个流程实例的过程，显示流程图，可是图片总是不显示

下面是要显示图片的jsp页面的代码

String path = request.getContextPath();

%>

String processInstanceId = request.getParameter("id");

ProcessEngine processEngine = Configuration.getProcessEngine();

RepositoryService repositoryService = processEngine.getRepositoryService();

ExecutionService executionService = processEngine.getExecutionService();

ProcessInstance processInstance = executionService.findProcessInstanceById(processInstanceId);

Set activeNames = processInstance.findActiveActivityNames();

ActivityCoordinates ac = repositoryService.getActivityCoordinates(processInstance.getProcessDefinitionId(), activeNames.iterator().next());

%>

HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

My JSP ""view.jsp"" starting page

/jbpm/jbpm_drawImage?id=" style="position:absolute; left: 0px; top: 0px;"/>

下面代码是上面img获取图片的struts2代码

public String drawImage() throws IOException {

String processInstanceId = request.getParameter("id");

ProcessEngine processEngine = Configuration.getProcessEngine();

RepositoryService repositoryService = processEngine.getRepositoryService();

ExecutionService executionService = processEngine.getExecutionService();

ProcessInstance processInstance = executionService.findProcessInstanceById(processInstanceId);

String processDefinitionId = processInstance.getProcessDefinitionId();

ProcessDefinition processDefinition = repositoryService.createProcessDefinitionQuery()

.processDefinitionId(processDefinitionId)

.uniqueResult();

InputStream inputStream = repositoryService.getResourceAsStream(processDefinition.getDeploymentId(), processDefinition.getImageResourceName());

System.err.println(processDefinition.getImageResourceName()); //输出结果为leave.png,是正确的

byte[] b = new byte[1024*4];

int len = -1;

while((len = inputStream.read(b, 0, 1024*4)) != -1) {

System.err.println(len);//输出结果为2518,说明有读取到数据

response.getOutputStream().write(b, 0, len);

}

return null;

}

当页面转到上面要显示图片的jsp时，显示的小红叉

我用的是jbpm4.3