多线程处理一个大的list

1.集合切分工具类

public class SplitListUtils {

    /**
     * 拆分集合
     *
     * @param <T> 泛型对象
     * @param resList 需要拆分的集合
     * @param subListLength 每个子集合的元素个数
     * @return 返回拆分后的各个集合组成的列表
     * 代码里面用到了guava和common的结合工具类
     **/
    public static <T> List<List<T>> split(List<T> resList, int subListLength) {
        if (CollectionUtils.isEmpty(resList) || subListLength <= 0) {
            return Lists.newArrayList();
        }
        List<List<T>> ret = Lists.newArrayList();
        int size = resList.size();
        if (size <= subListLength) {
            // 数据量不足 subListLength 指定的大小
            ret.add(resList);
        } else {
            int pre = size / subListLength;
            int last = size % subListLength;
            // 前面pre个集合，每个大小都是 subListLength 个元素
            for (int i = 0; i < pre; i++) {
                List<T> itemList = Lists.newArrayList();
                for (int j = 0; j < subListLength; j++) {
                    itemList.add(resList.get(i * subListLength + j));
                }
                ret.add(itemList);
            }
            // last的进行处理
            if (last > 0) {
                List<T> itemList = Lists.newArrayList();
                for (int i = 0; i < last; i++) {
                    itemList.add(resList.get(pre * subListLength + i));
                }
                ret.add(itemList);
            }
        }
        return ret;
    }

}

2.多线程演示代码

                List<List<String>> splitNList = SplitListUtils.split(titles, 20);
                CountDownLatch countDownLatch = new CountDownLatch(splitNList.size());
                BlockingQueue<Future<Map<String,List<CblWorksHistory>>>> queue = new LinkedBlockingQueue<>();
                Set<String> articleTitleSet = new HashSet<>();
                Set<String> videoTitleSet = new HashSet<>();
                for (List<String> singleList : splitNList) {
                    // 线程池执行
                    Future<Map<String,List<CblWorksHistory>>> future = threadPoolExecutor.submit(() -> {
                        for (String title : singleList) {
                            //此处进行业务处理
                        }
                        map.put("al",articleList);
                        map.put("vl",videoList);
                        return map;
                    });
                    queue.add(future);
                    countDownLatch.countDown();
                }
                try {
                    // 让当前线程处于阻塞状态，直到锁存器计数为零
                    countDownLatch.await();
                    // 汇总结果
                    for(Future<Map<String,List<CblWorksHistory>>> future : queue) {
                        Map<String,List<CblWorksHistory>> map = future.get();
                        list.addAll(map.get("al"));
                        list1.addAll(map.get("vl"));
                    }
                } catch (Exception e) {
                    log.error("单篇稿件缓存周榜数据时出错");
                }