Feign实现微服务间调用返回stream-蒲公英云

Feign实现微服务间调用返回stream

叁歲伎倆 2022-01-22 07:55 1126阅读 0赞

今天来讲述一下fegin的调用返回stream，得到stream我们可以下载，写入到页面展示图片等；
我们就开始讲述一下：

服务提供者流接口

@RequestMapping(value = “feginProcessDiagram”, method = RequestMethod.GET, consumes = MediaType.APPLICATION_JSON_UTF8_VALUE)
public void genFeginProcessDiagram(HttpServletResponse httpServletResponse, String processId) throws Exception {

ProcessInstance pi = runtimeService.createProcessInstanceQuery().processInstanceId(processId).singleResult();
//流程走完的不显示图
if (pi == null) {
    return;
}
Task task = taskService.createTaskQuery().processInstanceId(pi.getId()).singleResult();
//使用流程实例ID，查询正在执行的执行对象表，返回流程实例对象
String InstanceId = task.getProcessInstanceId();
List < Execution > executions = runtimeService.createExecutionQuery().processInstanceId(InstanceId).list();
//得到正在执行的Activity的Id
List < String > activityIds = new ArrayList < > ();
List < String > flows = new ArrayList < > ();
for (Execution exe: executions) {
    List < String > ids = runtimeService.getActiveActivityIds(exe.getId());
    activityIds.addAll(ids);
}
//获取流程图
BpmnModel bpmnModel = repositoryService.getBpmnModel(pi.getProcessDefinitionId());
ProcessEngineConfiguration engconf = processEngine.getProcessEngineConfiguration();
ProcessDiagramGenerator diagramGenerator = engconf.getProcessDiagramGenerator();
InputStream in = diagramGenerator.generateDiagram(bpmnModel, "png", activityIds, flows, engconf.getActivityFontName(),
    engconf.getLabelFontName(), engconf.getAnnotationFontName(), engconf.getClassLoader(), 1.0, true);
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();
    }
}

}

服务提供者远程调用接口

@RequestMapping(value = “/expense/feginProcessDiagram”,method = RequestMethod.GET,consumes = MediaType.APPLICATION_JSON_UTF8_VALUE)
Response genFeginProcessDiagram(@RequestParam(“httpServletResponse”) HttpServletResponse httpServletResponse, @RequestParam(“processId”) String processId) throws Exception;

用feign.Response来接收

服务提供者下载文件接口

@RequestMapping(value = “ribbonProcessDiagram/{processId}”)
public void genProcessDiagram1(HttpServletResponse httpServletResponse, @PathVariable String processId) throws Exception {

ResponseEntity<Resource> entity = restTemplate.postForEntity("http://microservice-flowable/expense/ribbonProcessDiagram/{processId}", processId, Resource.class,processId);
InputStream in = entity.getBody().getInputStream();
System.out.println(in);
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();
  }
}