Java八股文面试之框架篇(SpringBoot)

 1、先加载全部数据，然后把数据按照20条一页进行加载（不需要UI主动去调分页）

class PageLoad extends Thread {
        int page = 0;
        List<MultiItemEntity> cBillPickSelectUIS;

        public PageLoad(List<MultiItemEntity> entitys) {
            Log.e("TAG","分页加载===");
            cBillPickSelectUIS = entitys;
        }

        public void run() {
            if (cBillPickSelectUIS == null) return;
            if (cBillPickSelectUIS.size() < 20) {
                requireActivity().runOnUiThread(() -> { // 这里使用handle去更新就不需要用到requireActivity()
                    mSelAdapter.setNewData(cBillPickSelectUIS);
                });

            } else {
                HashMap<Integer, List<MultiItemEntity>> hashMap = splitArray(cBillPickSelectUIS, 20);
                hashMap.get(page);
                hashMap.forEach((integer, multiItemEntities) -> {

//                    if (integer>4) return; //只展示前4条
                    try {
                        Thread.sleep(1000);
                        requireActivity().runOnUiThread(() -> {// 这里使用handle去更新就不需要用到requireActivity()
                            mSelAdapter.addData(multiItemEntities);
                            mSelAdapter.notifyDataSetChanged();
                        });
                    } catch (InterruptedException e) {
                        throw new RuntimeException(e);
                    }
                });
            }
        }
        public HashMap<Integer, List<MultiItemEntity>> splitArray(List<MultiItemEntity> originalArray, int chunkSize) {
            if (originalArray == null || originalArray.size() == 0 || chunkSize <= 0) {
                return new HashMap();
            }
            //这里如何把originalArray数组拆分成多个数组？每个数组50长度，然后返回HashMap
            HashMap<Integer, List<MultiItemEntity>> resultMap = new HashMap<>();
            int index = 0;
            for (int i = 0; i < originalArray.size(); i += chunkSize) {
                List<MultiItemEntity> subList = new ArrayList<>(originalArray.subList(i, Math.min(i + chunkSize, originalArray.size())));
                resultMap.put(index++, subList);
            }
            return resultMap;
        }
    }

调用：

new PageLoad(cBillPickSelectUIS).start();

2、异步任务AsyncTask

private class LoadDataTask extends AsyncTask<Void, Void, List<MultiItemEntity>> {
        private int selflag;
        private int patienttypeflag;
        private String sDate;
        private String eDate;
        private List<CPickBillSelectDept> dlist;
        private int pickOrCancel;

        public LoadDataTask(int selflag, int patienttypeflag, String sDate, String eDate, List<CPickBillSelectDept> dlist, int pickOrCancel) {
            this.selflag = selflag;
            this.patienttypeflag = patienttypeflag;
            this.sDate = sDate;
            this.eDate = eDate;
            this.dlist = dlist;
            this.pickOrCancel = pickOrCancel;
        }

        @Override
        protected List<MultiItemEntity> doInBackground(Void... voids) {
            return billPickRepository.getPickBillSelList(selflag, patienttypeflag, sDate, eDate, dlist, pickOrCancel);// 耗时任务
        }

        @Override
        protected void onPostExecute(List<MultiItemEntity> result) {
            // 在这里处理后台任务返回的结果，例如更新UI
            billpicksellist.postValue(result);
        }
    }