多线程处理多次Http请求慢的问题

业务场景：前端调Java接口，接口需要多次请求http请求，因为是顺序执行，每个http耗时很长，大概5秒左右，但是叠加起来是很恐怖的，有必要做成多线程去处理。

大体思路：多线程去do任务，使用CountDownLatch进行计数当前线程执行结束，然后调用await()方法，继续向下执行

上代码：

public String picMark(Model model, HttpServletRequest request) throws Exception {
    Map paramPicMap = picAssessService.getParamPic();//查库
    CountDownLatch latch=new CountDownLatch(2);
    Worker worker1=new Worker("DAMO", latch,paramPicMap);//走http比较慢
    Worker worker2=new Worker("YUSHI",  latch,paramPicMap);//走http比较慢
    worker1.start();//
    worker2.start();//
    //步骤3、4、调用await放过，等待所有线程完成工作
    latch.await();
    if(worker1.resultList == null  && worker2.resultList == null ){
       model.addAttribute("message","暂无可标注的数据");
    }
    model.addAttribute("picAssessList",worker1.resultList);
    model.addAttribute("newPicAssessList",worker2.resultList);
    model.addAttribute("paramPicUrl",paramPicMap.get("url"));
    return "modules/beyond/picAssess/picAssessForm";
}

class Worker extends Thread{
    CountDownLatch latch;
    String algorithmType;
    List resultList;
    Map paramPicMap;
    public Worker(String algorithmType,CountDownLatch latch,Map paramPicMap){
        this.algorithmType=algorithmType;
        this.latch=latch;
        this.paramPicMap=paramPicMap;
    }
    @Override
    public void run(){
        doWork(algorithmType,paramPicMap);//工作逻辑方法
        latch.countDown();//每完成一次减1
    }

    private void doWork(String algorithmType,Map paramPicMap){
        try {
            if("DAMO".equals(algorithmType)){
                this.resultList=picAssessService.getSearchPicList(paramPicMap);//实际需要走http的方法，很耗时
            }else if("YUSHI".equals(algorithmType)){
                this.resultList=picAssessService.getNewSearchPicList(paramPicMap);//实际需要走http的方法，很耗时
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

使用后耗时减少了近一倍，当http越多节省的时间越多！！