Question

我正在尝试使用线程进行并行调用。为此，我使用Callable接口，因为我需要一个参数。问题是我在一个循环中用参数使线程成为线程，并且传递的值总是被覆盖，因此当它到达 call（）方法时，它总是具有最后一个传递的值。

private HotelResponseDto getHotelsCall(HotelRequest request) {
    Set<Suggestion> suggestions = repository.findByHistoryId(request.getId());
    List<Callable<HotelWrapperDto>> calls = new ArrayList<>();
    ExecutorService executor = new ScheduledThreadPoolExecutor(suggestions.size());

    for (Suggestion s : suggestions) {
        request.setCityCode(s.getName());
        calls.add(new MyCallable(request)); //beginning of the issue
    }

    List<Future<HotelWrapperDto>> results = null;

    try {
        results = executor.invokeAll(calls);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }

    List<HotelWrapperDto> wrappers = new ArrayList<>();

    for (Future<HotelWrapperDto> f : Objects.requireNonNull(results)) {
        try {
            wrappers.add(f.get());
        } catch (InterruptedException | ExecutionException e) {
            log.error("Something didn't work.");
        }
    }

    HotelResponseDto response = new HotelResponseDto();
    response.setWrappers(wrappers);
    return response;
}

这是MyCallable类

class MyCallable implements Callable<HotelWrapperDto> {

    private HotelRequest hotel;

    MyCallable(HotelRequest request) {
        hotel = request;
       //Here is the problem
       //Because I call this constructor in a loop,
       //hotel variable is always overwritten and in the end
       //I get the last result for every iteration 
    }

    @Override
    public HotelWrapperDto call() {
        HotelRequest hotelRequest = helper.createHotelRequest(hotel);
        HotelWrapperDto wrapper = hotelService.getHotels(hotelRequest);

        return wrapper;
    }
}

我曾骑过其他有关带有参数的线程的文章，但没有找到任何解决方案。如何找到适合我的情况的解决方案？（我稍后会清理代码）

Java-可调用的构造函数覆盖变量

0 个答案: