多线程并发查询mysql数据库中的数据

时间:2022-10-24 17:56:03
用10个一次拉2吨的卡车代替1个一次拉10吨的卡车。前提是有资源折腾,比如线程池,多核cpu,也要考虑线程的切换代价。把java服务器和数据库服务器综合利用起来,传统的方式是java服务器发送一条指令给数据库就坐等喝茶拿结果,数据库累个半死才出结果,而且出力不讨好,嫌干活慢,现在也要让java服务器也要干点事,这样大家都心里比较平衡点。

List<CompletableFuture<List<TimesAndAmount>>> allStationsTimesAmount =
inputParamArrayList.stream()
.map(inputParam -> CompletableFuture.supplyAsync(() ->nonOilSalesAndPerCustomerTransactionDao.getTimesHoursInterval(inputParam), executorService))
.collect(Collectors.toList());

List<List<TimesAndAmount>> timesAmount = allStationsTimesAmount.stream()
.map(CompletableFuture::join)
.collect(Collectors.toList());


private List<String> getBarcodeList(String[] deptIds, String[] ids) {

List<String> list = new ArrayList<>();
List<String> list1 = new ArrayList<>();
if (deptIds != null){
list = Arrays.asList(deptIds);

List<CompletableFuture<List<String>>> allBarcodes =
list.stream()
.map(inputParam -> CompletableFuture.supplyAsync(() ->nonOilSalesAndPerCustomerTransactionDao.getBarcodesBydeptid(inputParam), executorService))
.collect(Collectors.toList());

List<List<String>> listList = allBarcodes.stream()
.map(CompletableFuture::join)
.collect(Collectors.toList());

//List<List<String>> 转换为List<String> ,使用flatMap

list1 =
listList.stream()
.flatMap(inner -> inner.stream()).collect(Collectors.toList());


}

if (ids != null){
list1.addAll(Arrays.asList(ids));
}

return list1;

}