list集合分组拆分

# n组 

public static <T> List<List<T>> averageAssign(List<T> source, int n) {

        List<List<T>> result = Lists.newArrayList();
        int renumber = source.size() % n;
        int number = source.size() / n;
        int offset = 0;
        for (int i = 0; i < n; i++) {
            List<T> value;
            if (renumber > 0) {
                value = source.subList(i * number + offset, (i + 1) * number + offset + 1);
                renumber--;
                offset++;
            } else {
                value = source.subList(i * number + offset, (i + 1) * number + offset);
            }
            result.add(value);
        }
        return result;
    }

subLists = averageAssign(dtoList, 4);

List<CompletableFuture<Void>> cfList = new ArrayList<>(4);
for(List<Integer> subList: subLists) {
    cfList.add(CompletableFuture.runAsync(() -> batchRun(null, subList, null)));
}
CompletableFuture.allOf(cfList.toArray(new CompletableFuture[0])).join();