多线程从数据库中分页读，单线程将所有结果保存的数据库_JAVA_编程开发_程序员俱乐部

class="java">
public class OrderReadThread implements Runnable {

    private List<Map<String, Object>> orderList;
    private BaseDalClient dalClient;
    private Map<String, Object> params;
    private int totalRecords;
    private CyclicBarrier cyclicBarrier;

    @SuppressWarnings({ "rawtypes", "unchecked" })
    @Override
    public void run() {
        // 每个线程分页查询，最终将结果放入公共的orderList
        Page<?> pageInfo = dalClient.queryForListPage("eps.UserRegisterServiceImpl.selectOrderList", params,
                totalRecords);
        List tempList = pageInfo.getList();

        orderList.addAll(tempList);
        try {
            // 子线程执行结束,等待其他未执行完的线程，如果所有线程都执行结束即执行同步线程
            cyclicBarrier.await();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (BrokenBarrierException e) {
            e.printStackTrace();
        }
    }

    public void setOrderList(List<Map<String, Object>> orderList) {
        this.orderList = orderList;
    }

    public void setDalClient(BaseDalClient dalClient) {
        this.dalClient = dalClient;
    }

    public void setParams(Map<String, Object> params) {
        this.params = params;
    }

    public void setTotalRecords(int totalRecords) {
        this.totalRecords = totalRecords;
    }

    public void setCyclicBarrier(CyclicBarrier cyclicBarrier) {
        this.cyclicBarrier = cyclicBarrier;
    }

}

public class FileWriteTaskThread implements Runnable {

    private List<Map<String, Object>> orderList;

    public FileWriteTaskThread(List<Map<String, Object>> orderList) {
        this.orderList = orderList;
    }

    @Override
    public void run() {
        System.out.println("****************将所有子线程统计的最终的结果保存到文件中F*******************");

        String outFileName = "order" + getCurrentTimeStr() + ".txt";
        String outFilePath = "d:/order/" + outFileName;
        BufferedWriter bw = null;
        try {
            bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(outFilePath), "UTF-8"));
            for (Map<String, Object> order : orderList) {
                StringBuilder line = new StringBuilder(200);

                line.append(MapUtils.getString(order, "b2corderno", "")).append(",")
                        .append(MapUtils.getString(order, "phonenum", "")).append(",")
                        .append(MapUtils.getString(order, "customername", "")).append(",")
                        .append(MapUtils.getString(order, "customeraddress", "")).append(",")
                        .append(MapUtils.getString(order, "suppliercode", ""));

                bw.write(line.toString());
                bw.newLine();
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (bw != null) {
                IOUtils.closeQuietly(bw);
            }
        }

    }

    private String getCurrentTimeStr() {
        Date d = new Date();
        SimpleDateFormat format = new SimpleDateFormat("yyyyMMddHHmmss");
        return format.format(d);
    }

}

 /**
     * 每次查询1000条
     */
    private static final int PERCENT_DOWNLOAD_NUM = 1000;

    public static void main(String[] args) {
        // 启动Spring容器
        ApplicationContext context = new FileSystemXmlApplicationContext(
                "file:src/main/webapp/WEB-INF/applicationContext.xml");
        // 获取数据库操作类
        BaseDalClient dalClient = context.getBean("dalClient", BaseDalClient.class);
        // 查询总记录数
        int totalRecords = dalClient
                .queryForObject("eps.UserRegisterServiceImpl.selectOrderCount", null, Integer.class);

        int temp = totalRecords / PERCENT_DOWNLOAD_NUM;
        int queryCount = (totalRecords % PERCENT_DOWNLOAD_NUM) != 0 ? temp + 1 : temp;

        List<Map<String, Object>> orderList = Collections.synchronizedList(new ArrayList<Map<String, Object>>());// 线程安全的List
        // 同步辅助类,当所有子线程全部执行结束后来执行不同辅助类指定的同步线程FileWriteTaskThread
        CyclicBarrier cyclicBarrier = new CyclicBarrier(queryCount, new FileWriteTaskThread(orderList));
        for (int i = 1; i <= queryCount; i++) {
            Map<String, Object> params = new HashMap<String, Object>();
            params.put("pageSize", PERCENT_DOWNLOAD_NUM);
            params.put("page", i);

            OrderReadThread orderReadThread = new OrderReadThread();
            orderReadThread.setDalClient(dalClient);
            orderReadThread.setOrderList(orderList);
            orderReadThread.setParams(params);
            orderReadThread.setTotalRecords(totalRecords);
            orderReadThread.setCyclicBarrier(cyclicBarrier);

            // 启动多线程来从数据库中分页读取数据
            Thread thread = new Thread(orderReadThread);
            thread.start();
        }
    }