java - 带参数的 for 循环中的多线程

Question

我相信得到的数据是错误的，因为实例变量不是线程安全的。

我尝试使用多线程，基于列表一次打开(最多)13 个线程。我在服务中使用它，需要将参数传递到 run 方法中，因此我创建了一些实例变量并设置它们。我还希望在继续第一个 for 循环的下一次迭代之前执行这十三个方法

private EnergyPortalGroup superGroup;
private EnergyPortalSubGroups singleSubGroup;
private BillingPeriod singlePeriod;
private DateTime[] dateTimeArray;

private void parseGroup(EnergyPortalGroup superGroup) throws InterruptedException{
    EnergyPortalSubGroupsCriteria criteria = new EnergyPortalSubGroupsCriteria();
    criteria.setGroupId(superGroup.getId());
    List<EnergyPortalSubGroups> wholeSubGroupList = subgroupsFactory.readList(criteria);
    for (EnergyPortalSubGroups singleSubGroup : wholeSubGroupList){
        this.singleSubGroup = singleSubGroup;
        this.deleteSubGroupRecordsFromDB(singleSubGroup);
        List<BillingPeriod> billingPeriodList = this.getPreviousTwelveBillingPeriods(singleSubGroup, superGroup);   
        if (billingPeriodList != null && billingPeriodList.size() > 0){
            Thread[] threads = new Thread[billingPeriodList.size()];
            for (int i = 0; i < billingPeriodList.size(); i++){
                this.singlePeriod = billingPeriodList.get(i);
                threads[i] = new Thread(this);
                threads[i].start();
            }               
            for (Thread thread : threads){
                thread.join();
            }
        }
    }
}

这是我重写的运行方法:

@Override
public void run(){
    List<GroupSummarization> groupSummarizationsToWriteList = new ArrayList<>();    
    WidgetDataSummationHolder holder = new WidgetDataSummationHolder();
    holder = energyPortalService.getEnergyPortalWidgetsSummedData(singleSubGroup, null, null, singlePeriod);    
    parseSummationHolder(groupSummarizationsToWriteList, holder, singleSubGroup, dateTimeArray, singlePeriod);
    processBatchLists(groupSummarizationsToWriteList, superGroup, singlePeriod);
}

任何人都可以帮助我确保该线程安全吗？我显然是多线程新手，我尝试使用构造函数传递这些变量，但我有一些为空的 Autowiring 服务，并且我在这一行得到一个空指针 holder = energyPortalService.getEnergyPortalWidgetsSummedData(singleSubGroup, null, null, singlePeriod);

Answer 1

根据您提供的代码，energyPortalService 有时不能为 null，有时则不能为 null。如果当你启动一个新的线程(this)时它不为空，那么如果你要使用一个新的线程(()-> {...});

(既然你正在谈论 Autowiring ，我会假设 osgi 和 aop 以及此类邪恶行为可能会发生很多错误。)