Question

我从数据库中获取作业。我想从DB获取记录是单线程的。一旦我完成了所有工作，我希望它们可以并行执行多个线程。

Answer 1

正如你所说，你正在使用Spring，我建议你查一下their documentation。

然后，您可以让您的线程查询数据库将您的工作（包含在Callable或Runnable中）提交到ThreadPoolTaskExecutor。

Answer 2

首先从数据库中提取记录以进行处理。
我正在与客户分组记录。

我正在将每个客户的处理传递给线程池。

.....
@Autowired
ThreadPoolTaskExecutor taskExecutor;

@Autowired
private ApplicationContext applicationContext;

@Transactional
public void processPendingPayments() {
    logger.debug("ProcessPendingPayments.processPendingPayments begins");
    logger.info("startTime::" + System.currentTimeMillis());
    List<PaymentRequestEntity> recordsPendingForPayment = getRecordsPendingForPayment();

    // Group Requests with Customers
    Map<String, List<PaymentRequestEntity>> customerPaymentRequestsMap = getPendingRecordsGroupedByCustomer(
            recordsPendingForPayment);

    // process Payment requests for customers
    for (String customerId : customerPaymentRequestsMap.keySet()) {

        CustomerPaymentRequestProcessor customerPaymentRequestProcessor = (CustomerPaymentRequestProcessor) applicationContext
                .getBean("customerPaymentRequestProcessor");
        customerPaymentRequestProcessor.setStrCustomerId(customerId);
        customerPaymentRequestProcessor.setCustomerPaymentRequestsMap(customerPaymentRequestsMap);
        taskExecutor.execute(customerPaymentRequestProcessor);

    }
    logger.info("endTime::" + System.currentTimeMillis());
    logger.debug("ProcessPendingPayments.processPendingPayments ends");
}
........

以下是Runnable类的代码，用于处理每个客户的记录

@Component
@Scope("prototype")
public class CustomerPaymentRequestProcessor implements Runnable {

    private static final Logger logger = LoggerFactory.getLogger(CustomerPaymentRequestProcessor.class);

    private String strCustomerId;

    private Map<String, List<PaymentRequestEntity>> customerPaymentRequestsMap;

    private final String REQUEST_TYPE_BALANCE = "Balance";

    @Autowired
    private BalanceServiceImpl balanceServiceImpl;

    @Autowired
    PendingPaymentsSequenceProcessor pendingPaymentsSequenceProcessor;

    @Autowired
    CustomerAuditServiceImpl customerAuditServiceImpl;

    public CustomerPaymentRequestProcessor() {

    }

    public CustomerPaymentRequestProcessor(String strCustomerId,
            Map<String, List<PaymentRequestEntity>> customerPaymentRequestsMap) {
        super();
        this.strCustomerId = strCustomerId;
        this.customerPaymentRequestsMap = customerPaymentRequestsMap;
    }

    @Override
    public void run() {
        logger.debug("CustomerPaymentRequestProcessor.run starts");
        List<PaymentRequestEntity> paymentRequests = getCustomerPaymentRequestsMap().get(getStrCustomerId());
        for (PaymentRequestEntity paymentRequest : paymentRequests) {

            CustomerBalanceResponse customerBalanceResponse = processPaymentRequest(paymentRequest);
            if (!customerBalanceResponse.isCustomerHasBalance()
                    && REQUEST_TYPE_BALANCE.equals(paymentRequest.getRequestType())) {
                break;
            }

        }
        logger.debug("CustomerPaymentRequestProcessor.run ends");
    }
    ....
    ....
    }

通过一个线程获取作业，但并行执行多个线程的作业

2 个答案: