多线程处理list集合

记录一次多线程处理list集合的过程
方法：

//计数
 static AtomicInteger count = new AtomicInteger(0);
 //处理方法
 public String moFee(List<JSONObject> list, final int nThreads)
            throws Exception {
    
    
        if (list == null || list.isEmpty()) {
    
    
            return null;
        }
        StringBuffer ret = new StringBuffer();
        int size = list.size();

        ExecutorService executorService = Executors.newFixedThreadPool(nThreads);
        List<Future<String>> futures = new ArrayList<Future<String>>(nThreads);
        for (int i = 0; i < nThreads; i++) {
    
    
            final List<JSONObject> subList = list.subList(size / nThreads * i, size / nThreads * (i + 1));
            Callable<String> task = new Callable<String>() {
    
    
                @Override
                public String call() throws Exception {
    
    
                    String currentMonth = DateUtil.getYearMonth(new Date());
                    for (JSONObject jsonObject : subList) {
    
    
                       // 处理逻辑
                       //todo
                        count.getAndIncrement();
                        System.out.println(count.get());
                        System.out.println("===========================>");
                    }
                    return "";
                }
            };
            futures.add(executorService.submit(task));
        }
        executorService.shutdown();
        while (!executorService.awaitTermination(5, TimeUnit.SECONDS)) {
    
    
            System.out.println("线程池没有关闭");
        }
        return ret.toString();
    }